Jeep TJ Axle Upgrades HPD30/Rubicon D44

[KCStudly]

Thanks. It seems to be the way things go for me. I spend a lot of time tweaking, preparing, fitting, basically sweating all of the details; and then when it finally comes together it usually does so in big stages.

It's taking longer than I had hoped, but at least it is turning out well. The Jeep will be like a whole different vehicle with much improved driveability, so I'm looking forward to that. Should have done this years ago.

[lfhoward]

KC, thanks for the detailed description of your differential project! It has been super interesting to see what is involved in regearing a diff. I have been thinking of regearing from the stock 3.73 ratio to a 4.10 ratio in my Jeep to help with towing and fuel economy, since I am running larger tires than stock. Your posts have taught me two things: 1) I don't have the equipment I would need to do it myself, and 2) this is a complicated and precision-demanding process! I think I will have a shop do the work if I ever decide to pull the trigger on a regear. Kudos to you for doing it yourself though! And thanks for the interesting read!

[KCStudly]

Thanks, LFH!

Doing it myself, vs. just buying a new crate axle I figure my cash outlay (including rental car fees for 3 wks) is only about half ($1600 dollars or so, about the cost of a used takeout axle of this pedigree... I got a deal on mine because it was broken). If I had to add labor to pay a shop to do it, then that crate axle really starts to look much more appealing.

Having access to the surface grinder allowed me to get around some of my personal hangups with the cheesy little shims that came in the setup kit, but probably wasn't completely necessary; I read somewhere that you can buy a master setup shim kit, including every thickness OEM shim, for around $360, most of which you won't need. With a lathe and a lapping plate you might be able to make your own, but with a time penalty; most people just use the ones that come in the aftermarket kits.

[KCStudly]

Nasty dirty work. This is why I stopped liking doing work on my own cars. Tonight was like that.

When I arrived Karl had already hitched up to the car trailer and dragged it back down closer to the shop so we could unload the Jeep. Got it in, chocked the front wheels, and got the back up on jack stands just in front of the trailing arms. Wheels off and the driver’s side brake drum came relatively easily. Passenger side will need to have the adjuster star wheel backed off. Found a broken spring in the driver’s side brake shoe assembly, probably installed wrong and wore thru.

The rear driveshaft has a rubber bellows at the transfer case end covering the slip yoke. This is held on with crimp style band clamps, so I just undid the pinion yoke straps and used a bungee cord to hold the driveshaft up (mostly) out of the way for now (didn’t want to risk having transfer case lube draining out). I'll probably have to cut one of the band clamps to pull the driveshaft out so that I can swap in the new hybrid U-joint, but this worked for now.

Backing off on the parking brake adjuster was a pain in the arse. I suspect the D35 failure was due to a bad pinion seal letting the lube out. Even if it was the other way around, once the pinion bearings were shot all of the lube came out anyway, and most of it is still slung up and spattered under the Jeep. You would think that this would help lubricate rusty/dirty fasteners, but it just makes a mess of things. I tried wearing disposable rubber glove, but they didn’t hold up to the rough service. Ended up using a plumber’s torch to heat the adjuster nut up (being very careful not to melt the plastic coating on the inner brake cable). This allowed the cable end lugs to be fished out of the brackets. Used a 1/2 inch box wrench pressed over the end of the brake cable to compress the one-way finger tabs to release the cable ends from the bracket {except one of the little prong ears bent over backwards and had to be nipped off with dikes (diagonal cutters)}.

Unbolted the parking brake cable mounting tabs from the trailing arms (this actually had to happen first in order to gain enough slack to release the cable end anchors). Used tube fitting wrenches to undo the hard brakes lines on the axle from the combination T-block/Vent tube banjo. Grabbed the vent tube band clamp crimp with vise grips and twisted it off (to be replaced by a worm drive clamp later). Undid the vent tube barb fitting to remove the T-block catching the brake fluid in a drain pan. Used the burp gun (cordless impact driver) to buzz off the lower shock absorber mounts and anti-sway bar saddles from their mounting pads on the axle, leaving the bar hanging from its end links (one bolt had to be wrench out most of the way… the impact driver wouldn’t move it at first).

The panhard bar bolt at the axle end is a Torx socket head into a blind weld nut and the Torx socket looked pretty rusty; so we decided that it would be easier to unbolt the bar from the chassis mount where it is held by a hex head bolt and accessible nut. Had to wrench that off due to lack of access for the burp gun. Had to jack up the driver’s side to take the strain off of the panhard to get the bolt out.

That left just the four trailing link bolts. Now I have just ripped thru this accounting in an abbreviated fashion, but trust me, not much was as easy as it sounds working mostly on my back with Karl handing me tools and support. Despite laying down a piece of cardboard and a mover’s blanket, and wearing my safety glasses, I managed to get grit in my eyes and gear oil (with grit) in my hair, and was black nearly up to my elbows. And it was 7 o’clock. So the trailing links and final removal will wait until Wednesday.

Kind of surprised (but not really) that most of the chassis bolts seem to be metric.

[KCStudly]

(Cross posted on TPCE build thread)
Having the proper gears in the Jeep, and not having to worry about breaking the weak D35 axle out in the middle of nowhere will be a big relief when it's done. I'll post more details soon, but the short catch-up version is that the backing plates and axle shafts are in; the brake assemblies are complete; and one of the new drums has been cleaned of its packing/shipping oil, installed and had its shoes adjusted. Today I do the other drum, make a new wire tie for the locker air hose (dealer couldn't find the parts on their little diagram), lube the diff, seal the cover, make new brake lines, remove the aftermarket panhard bar mount, and... if I get thru all of that... start installing it in the Jeep.

[KCStudly]

Picture dump and progress update. Almost done… sorta.

I ended up having to cut the passenger side brake drum off using a cut off wheel in the 4-1/2 inch grinder. Basically I cut thru the rim of the drum from the backing plate to the wheel flange in two locations 180 deg apart. Due to the labyrinth seal between the drum and backing plate I couldn’t cut quite all the way thru w/o getting into the backing plate, but the drum is cast iron, so once most of the way thru I stuck a heavy screwdriver in the cut and whacked it with a hammer to snap the rest of the way. This allowed me to open the drum up enough to free the shoes and pull the drum off.

As it turns out, the shoes weren’t especially worn, but the passenger side drum was worn a lot more than the driver’s side. So my hopes to reuse these parts fell thru, and I ended up buying all new drums, shoes, and hardware kits. Just as well, but another $110 or so with a can of Brake Kleen and couple of sticks of new hard line.

Here’s the new driver’s side axle with the new shoes and spring kit installed.


I’ve done plenty of brake jobs in my time, but hadn’t ever done one with this “modern” style of cable operated adjuster. I took plenty of pictures for reference purposes while taking the D35 apart. Still, included in the new hardware/spring kit were a couple of horse shoe shaped clips and wave washers that did not come out of the OEM assembly. I tried to search on-line to see what I was missing, apparently they weren’t important enough to warrant mention. I thought the horse shoe clips might be a throw away tool for setting the shoe retainer spring cups on the pins using vice grips, but they didn’t fit in the detents inside of the spring cups (I have the driver tool for this so used it anyway). The wave washers are still a mystery.

The parking brake adjuster assembly.


The street side went together fine. On the curb side I had a hell of a time with the guide sheave for the adjuster cable. It is supposed to seat under the rear shoe return spring, but the sheave kept popping out of the hole in the shoe rib as I tried to seat the cable on the post. Finally I just ignored it going over the sheave, put the loop over the post, and went ahead and installed the spring, then I was easily able to hold the cable in the sheave and pop the sheave back into the hole under the tension of spring using a screw driver. All it took was frustration, time, and a trial and error approach.

Sprayed the drum down with brake cleaner, installed it with a couple of lug nuts to hold it on squarely, and adjusted the shoes out. First out enough to really drag, almost lock, and then backed off until just dragging a little. They need to be broken in.

That was yesterday.

Today I cleaned the street side drum, installed it and adjusted the shoes.


Back inside the diff cover, since I was not able to source the locker hose or wire clamps, I moved the OEM clamp up to the bulkhead barb fitting (since it was harder to access), and twisted my own wire tie out of 1/32nd SS TIG welding wire for the locker apply piston barb.


You can see the OEM clamp better here.


I double wrapped the wire, twisted it tight with vice grips, and trimmed it off clean with dikes (making sure to hold both of the tag ends so that they didn’t clip off and fall into the housing).


Both joints seemed to be plenty tight for the low pressure application.

If you have ever tried to squeeze 2 quarts of thick gear lube thru a rubber hose into a tiny fill plug while under your vehicle you would appreciate the total ease of removing the bottle cap and dumping it straight into the diff.


Something that totally irks me is when a guy puts a big 1/4 inch bead of sealer on a diff cover (or oil pan, or timing cover, or valve cover, etc.) and slaps the cover on. This can be quite risky if a big chunk of sealer breaks off inside and blocks an oil passage, or whatever. This is what I found on the D35 that had been serviced by the quick lube. There wasn’t any evidence of large chunks coming adrift, but there was enough squeeze out that it was dragging on the ring gear. Seriously. I get it; they don’t want call backs from people complaining that they have oil dripping in their driveways, but come on. And I am also not a fan of using just sealer instead of a gasket. In my experience the best method is a thin film of sealer on both sides of a gasket. Basically you smear the gasket on both sides leaving perhaps a 64th on both sides… just enough to color, but not so much that it is piled up.

I used one of the boxes the drums came in as a pallet to smear the gasket with Ultra Copper (which I am partial to). Gloved and gooey, so no picture of the gasket, but here is what the pallet looked like after the fact.


And here is the cover bolted up.


Note the very small, yet even, bead of squeeze out all the way around. It only takes a thou or so to fill any voids that the treated paper gasket doesn’t get, so unless your cover is grossly warped, more sealant is just a liability.


Oh yeah, BTW, since the dealer didn’t have the cover bolts in stock I had resolved to just reuse the mixture of OEM and Gr 8 bolts, but then when I took the D35 cover off I had a whole ‘nuther set of cover bolts at hand; so I cleaned some of those up and had a whole set of the serrated flange bolts to use. Same thing with the tube flange studs; rather than grinding a flat on the head of a replacement bolt, I just popped one of the studs out of the D35 and drove it into the flange on the D44 using a screw clamp as a press and socket as a spacer.

Here’s a look at the aftermarket panhard mount bracket. It bolts thru the OEM panhard mount bracket using an anti-crush sleeve in place of the stock panhard bar; had three (3) additional 5/16 bolts drilled thru and mounted to the factory mount; and was welded in two (2) locations to the axle tube along the bottom edge. This raised the panhard mount location several inches and rotated the angle to suit the PO’s higher lift and pinion angle required for a double cardan drive shaft CV joint… which I don’t have… so it had to go.


I used the cutoff wheel in the 4-1/2 inch grinder to cut the welds most of the way thru, unbolted the rest, pried it off the rest of the way, and then ground the rest of the weld beads down fair.

The axle also has aftermarket shock mounts. These include plates welded to the backs of the lower trailing arm mounts (boxing those in and making them stronger), and new ‘U’ brackets weld to those for the shock mounts. Best I can tell these were added to the previous vehicle while the axle was still installed. That meant that the OEM shock mounts had been crudely cut off using a recip saw, with large remnants still remaining. The new/improved lower shock mounts put the lower shock several inches out further on the axle, which in theory improves dampening (if it doesn’t change the shock geometry enough by laying it out more horizontally), but more importantly for a rotated rear, supposedly gains clearance with the springs. My concern was that if these aftermarket shock mounts don’t line up, or are of an inappropriate height for my 1-3/4 inch lift shocks, and I can’t just cut them free and rotate them on their existing plates, then I might have to resort back to OEM style shock mounts. No better time than the present to remove the original stubs and prep for this event,

Here I have already cut most of the remnants of the original shock mounts. Driver side first, then curb side.



Here I have used a flap sanding disc to remove the rest of the remnants.



Next I used a putty knife and screwdriver to go around and scrape muck, dirt and grease off of all of the mounting points. There was a large amount of hardened mud packed into the anti-sway bar mounts, enough junk overall to fill a dust pan.

When scrapping the grease out of the inside of the upper driver’s side trailing arm mount I was surprised to find the putty knife stopping hard on something very firm. There was a big step running right thru the bolt hole axis. After cleaning this up with a wire brush and solvent I found that some prior activity had attempted to cut the trailing arm bolt using a recip saw between the trailing arm bushing and the mount flange. Probably the same ‘Primitive Pete’ that cut the axle. The mount ear had been shaved at an angle practically more than half way thru its thickness all the way thru half of the bolt hole.


Unacceptable!

While Karl is well equipped, I don’t always know where all of his tools are, and sometimes he has much of them on the road with him. And this area was mostly inaccessible to a wheeled grinder. So I used a hand file to remove the burr off of the saw cut, opening the gouge up to accept a filler weld. I was going to weld this up using the small MIG, but Karl had just off loaded that out of the bed of his truck last night and presumably still had the shield gas regulator in the cab. So I ended up dragging the big TIG welder over and used that.

First I ran a bead right up the bottom of the cut filling that up and eliminating the sharp notch. Next I fanned a pass cladding some of the area that had been slashed away. Unfortunately when I got to the area adjacent to the bolt hole it washed away; so I let it cool and came back from the outside and filled it in on the edge of the hole using less heat. By building up a large bead of excess filler on the outside of the bolt hole, I was able to go back in from the inside, where the torch angle was not ideal, and fill the rest from the inside. One or two more passes to clad the inside, paying particular attention to the area around the hole where the bushing will bear, and a little make up on the top edge to fill in the under cutting from the first pass there, a lot of hand filing where the flap wheel couldn’t reach, and we get this.


Not pretty, but way better. A little more filing to square the bolt hole back up and she is good enough. Hell, she was in use before, but I could just not leave it like that for fear that the ear would tear right off at the stress riser.

Formed new brake hard lines. Particular attention paid to avoiding any rub spots, like around the spring perches. This was harder than it sounds; the factory bends were much tighter than either of my bending tools and I didn’t want to cave the tubing in. It always seems that I have trouble forming the double flared ends. Even the good quality Rigid brand tube clamp I have doesn’t want to clamp the small tubing hard enough that it doesn’t just push thru the flaring clamp tool. Eventually I found the technique that worked using a combination of my double flaring mandrel and press, and Karl’s clamp. The trick seemed to be to put a really good chamfer on the inside of the tiny 3/16 inch tube ID before attempting to form the first bubble.




The clamp adjacent to the passenger side upper trailing arm mount is attached with screws that are threaded straight thru the axle tube, so I smeared some sealant around these holes and bolts before securing, and made sure to slip the OEM rubber sleeve over the tube before forming the new end. This is right where the exhaust passes over the axle, too, so should be good for clearance with the exhaust pipe.

If I remember I will pick up some high heat black paint on the way out tomorrow. The brake drums and hard lines will look and last that much better with a little paint on them… nothing fancy, just a quick spray.

Just need to wipe road debris and grease off of the panhard bar, and get that loosely bolted to the axle mount before installation.

Hopefully everything will go relatively smoothly tomorrow and it will be back drivable. Hopefully.

[KCStudly]

After a long day the Jeep moved under its own power this evening. In fact, I drove it home.

I started to draft this, but just lost it all to a cut/paste error, so am discouraged to write it all out again. Oh well, here we go.

Installing the rear was a slog at times, but I worked thru it.

When the rear is up in position there isn’t enough room between the gas tank and axle side panhard mount bolt to get a ratchet and Torx driver in there. So at first I thought reassembly should be a reversal of disassembly, and the panhard bar should be attached to the axle first. But this proved to be too awkward trying to jack the rear up and slide it to the right while holding the bar up over the exhaust. Maybe if I had a second hand, but Karl was in the field. So I abandoned that idea and figured I could get the bar in later (fingers crossed).

The first thing that I could get lined up was the shock absorbers. These would normally go together near the end, but with the trouble I was having with the axle falling off of the jack, I went ahead and attached them first to prevent that.

Would have been nice to have a transmission jack or a custom cradle in place of the jack pad; the rear wanted to fall off of the jack pad and I couldn’t easily change the pinion angle to get the trailing link bolt holes lined up. I tried to prop up the pinion with a 2x4 and lower the pumpkin, pivoting off of the upper links to get the lowers lined up, but the board tilted and kicked out a couple of times just as it was within about 1/8th inch of aligning. On the third try I stopped it short of the board kicking out and used a ratchet strap from the axle tube near the brake flange to a point forward on the frame and pulled it in the rest of the way.

Once I had all of the trailing arm bolts in loose, I was able to drop the rearend out again, get the springs seated, and the panhard bar bolted up. Had to raise the axle back up to get the chassis side of the bar aligned and was looking for a spot to ratchet strap that, but it turned out to be unnecessary.

In order to keep the rubber bushings from binding you are supposed to lower the vehicle to ride height before tightening all of the chassis bolts. I may have been able to snake under there with the wheels on… it is a lifted Jeep on 31’s, after all… but instead I jacked the rearend up just until the jack stands got a little loose, simulating ride height, and then went around and tightened everything.

The small stuff went pretty easy, mostly because it had all been wiped clean and/or wire brushed… the brake line T-block and axle vent (used a little Ultra Copper on the vent tube threads); the parking brake and brake hose mountings at the trailing arms; and the parking brake adjuster.

On the other hand, the anti-sway bar mounting bolts did not cooperate. I should have run a tap thru the blind nuts on the axle mounting pads, but figured that would defeat the mechanical crimp feature. I did wire brush the bolts and sprayed both the nuts and bolts with PB Blaster, but when running the first couple of bolts in, before the clearance was even taken up, I managed to snap one of the bolts off. Curses.

Rather than deal with extracting the broken bolt and finding a new bolt, I decided to remove the sway bar instead, and deal with that another time.

About this time Karl arrived home and I enlisted his help to adjust the parking brake cable (still needs some adjustment), and bleed the brakes.

Earlier in the day I had pried open the Oetiker clamp securing the bellows boot to the rear driveshaft slip yoke, removed the driveshaft, and swapped the old U-joint out for the new cross over 1310/1330 joint. I used one of the vises on the old milling machine and some sockets to do the pressing. Something to be aware of: always make sure that the grease fitting is oriented so that it is in compression when being driven. The tapping for the grease fitting creates a stress riser in the joint, so is stronger in compression than it is in tension.

The driveshaft length with the new pinion yoke seemed to work out right, although I did not cycle the suspension fully, since I had already installed the springs. With the axle at simulated ride height there was enough free play to slide the shaft forward and swing the rear joint up to clear the pinion yoke, before sliding it back and seating the joint caps, but not a lot more; so perhaps 5/8 inch. Normally I would look for about 3/4 inch, but this should do okay. There really wasn't much more up travel in the axle with the extended bump stops; maybe just 3 or 4 inches.

I tried to reuse the Oetiker clamp on the slip yoke bellows, but ended up doing the same sort of wire tie clamp that I had used on the locker air hose. I didn’t want to use a regular worm drive band clamp for fear of throwing the shaft out of balance, and hadn’t managed to source a new clamp in the meantime.

One of the plastic center hub covers that slips into the wheel hub hole from behind was broken at its flange and couldn’t be used. Oh well.

While I was bolting the rear wheels back on, Karl dove under the front to make sure that the front drive shaft could be removed w/o loosing lube out of the transfer case. I was led to believe that it could be, but hadn’t checked before starting all of this. Despite being able to put the transfer case into 2-wheel Hi, you don’t want to run with different axle ratios. My understanding is that the lock up in the transfer case is similar to an automatic trans or motorcycle stacked disc wet clutch. So even when it is not locked up, you don’t want it to differentiate much elsewise wear will ensue.

At first we had a scare when Karl couldn’t see how the front drive shaft double cardan joint bolted to the front output yoke, but I got under there and felt up above the belly pan to find the bolt heads on the back of the output yoke. What we did find was that the front axle has a ton of backlash between its pinion and ring gear, so it is just as well that it will need to be regeared soon. Once the front drive shaft was out we also found that one of the U-joint caps in the cardan appeared to be worn out.

It’s not over yet. When I went to start the Jeep the battery was dead from having sat for so long and only starting it once without letting it charge. Karl whipped out his big charger and soon enough we had it running.

I decided to attempt to drive it home as a first test run and first break in. Just pulling it out of the barn I could tell it was much more drivable.

Now mind you that I don’t drive the Jeep every day. So I’m listening for every last little bump, squeak, pop and noise. The NV3550 trans always sounds like it is grinding rocks when it is in neutral with the clutch out; that is, unfortunately, normal reverse shaft backlash. And it is a Jeep with over 200k miles on it. First thing I noticed was a little whining sound with the clutch in or when decelerating. I want to think that this is the throwout bearing whining and I just hadn’t driven it recently enough to catch it (despite really wishing not to have to replace the throwout bearing), but why when decelerating? If I just matched the coast with enough gas to not be decelerating it went away, so maybe not throwout bearing, but maybe trans input bearing? Dunno.

I heard a bit of a clunk when pulling onto the main road and I got about a mile or two down the road before remembering that I had not tightened up the lower shock mounts. So I pulled over at the stone apron to the power lines and she died on low idle. She fired right back up but I figured the ignition wasn’t happy with the low voltage at idle with the drained battery. I climbed underneath, the diff felt just warm, and I made sure that the shock bolt nuts were still there and at least finger tight.

Drove back to the shop, tightened the shock mount bolts and listened. I was hearing a bubbling noise and wondered if it was the gear lube boiling, despite the housing being only warm to the touch.

Probably didn’t sit long enough to totally cool off before driving it all the way home. Once home, in our sloped driveway, I confirmed that the parking break needs further adjustment. After leaving it in gear and chocking the wheel I laid back under and felt the diff again. It was pretty hot but not so much that I couldn’t hold my hand on it. Not sure what to compare that too, but will be feeling hot diffs in the near future to see.

On drivability; oh what a difference! Despite not being able to really get into it until after the break in period, it is so much better taking off in 1st, and 5th gear is now totally useable. She can now pull any gear easily from 2k rpm without having to down shift, whereas before you would have to down shift from 3rd or forth, or be light footed in 2nd. Unfortunately, despite my expectations, the speedo is totally off (or at least it seems to be). Before, with the 3.07 gears and 31’s the speedo read low about 10/ct. At 55 indicated you were doing 60. Now, I was running at moderate highway speeds, guesstimating 55 or 60, and she was indicating 80 with cars going by me. I’ll check it with the GPS and see if I can figure out which speedo gear I need to correct it.

Still a little on pins and needles. Everything should be okay dokay, but with all of this time and money invested I would sure hate to have it all go bad. Never done this before, don’t cha’ know.

Hope she starts in the AM.

[lfhoward]

Congratulations for getting your Jeep driving again!!! This is not a small victory.

I think there is a small gear on the top of the diff or the transfer case that sends a signal (not sure if it is through a wire or a cable) to the speedometer. Check the TJ section of http://www.jeepforum.com, because this seems to be a common item people fix after they regear. (I have a Liberty so don't visit the TJ section much, but I have heard of this issue.)

[KCStudly]

Thanks, LFH. I believe there is a plastic speedo gear in the tail housing of the NV231 transfer case that can be swapped out for a different ratio. I don't recall at the moment if it has a pulse generator (I don't think so), or a std speedo cable (I think) after that. Later year Jeeps did switch to fully electronic and I think the only way to recalibrate those is with a programmer.

[KCStudly]

I found this web page to be quite informative on Jeep speedo gear changes, and ordered a new 37 tooth gear from E-Bay for $24.

[aggie79]

Congrats KC!

Thank you for the detailed explanations. Fascinating reading to me. Hopefully by observation and osmosis I picked up a little of your knowledge and skills!

[KCStudly]

Thanks for the positive feedback, Tom. It is much appreciated.

Last night I readjusted the brake shoes and parking brake. It's weird; The point where the hand lever starts to grab tracks with the cable adjustment made at the tie bar over the rear driveshaft... in other words, as the adjustment is taken up the point where the lever starts to get resistance gets lower and lower... and the point where the lever gets too tight to pull up any further also gets lower and lower, but the brakes never apply hard enough to fully hold the vehicle from rolling. At the moment I have it adjusted to where the handle only comes up about half way with all of my might, to the point where I have a hard time getting it to release again... and I can feel the brakes dragging a little bit... but I can still get out and push the jeep on a flat surface. This isn't new, but I thought with all fresh brake components and proper adjustment that it would at least work for a little while before needing adjustment again. The adjuster nut is pretty far up on the tie bar threaded stud, but the cables all looked good on visual inspection and moved freely to the extent that I could push them back and forth by hand when they were detached. I thought I got the struts that bridge across the shoe ribs properly located; if they weren't I would expect the hand lever to go all the way to the top and be unresponsive to adjustment.


Once I gave up on that, I dove back under and drilled out the snapped off anti-sway bar mount bolt. Center punched a prick mark first, then drilled with incrementally larger drills up to 11/32 for the M10x1.5 metric thread. Fortunately that last drill size took out all of the remaining parts of the bolt with zero damage to the female threads (Whoopee, that almost never happens!). Chased all female threads with a tap, and the remaining three (3) bolts with a thread die to where they all thread in easily by hand. Now I just need to source a replacement bolt. I would prefer to get the factory style bolt with captured washer, but would settle for a generic hex head and flat washer.

Have been scouring Tempest search for a suitable front axle core to rebuild and there are several options currently available in eastern PA; which is about the limit of what I am comfortable chasing down for in person pick-up ("road trip!"). Have more or less decided on a TJ (low pinion) or '98 or later XJ (high pinion) Dana 30. The TJ D44 front's are much rarer, cost a bunch more, aren't very much stronger because everything from the pumpkin out is Spicer D30 spec anyway. The HPD30 is preferred because it uses shims for the pinion preload (rather than a crush sleeve) and loads what is conventionally the "drive" side of the gear tooth (rather than the coast side), making it marginally stronger. There's a seller with one that has 3.55 gears, which is below the carrier split, but I already have a bare 3.92 and down (numerically higher) carrier that I think is the same for LP vs HP.

The ring gears on the D30 are only 7-1/8 inch diameter, but the common point of breakage is usually the axle u-joint. Just don't crank the wheel, stuff it into a hard obstacle and mash the gas pedal, and you should be okay... only "if" and "should".

Unfortunately the D30 4.10 gear set I purchased some time back is for a low pinion, so if I go the HP route I'll have to source a different set.

The axle tubes on the D30's are still somewhat thin, but can be sleeved internally so long as you stay with the stock size 27 spline axle shafts; which are available aftermarket in stronger chrome-moly ("chromo") alloy if you feel the need... or start breaking them. The consensus seems to be that you have to work pretty hard with tires larger than 35's to break them. The most torture I may put the Jeep thru would probably be the Unimog event and Larry's Rubicon hasn't broken anything yet, despite him always keeping the front locked up regardless of how hard he stuffs it and turns into obstacles, so I think the HPD30 would be a good compromise.

I guess I need to rename this thread: Jeep TJ Axle Upgrades HPD30/Rubicon D44 .

[KCStudly]

Road trip to Mayfield, PA tomorrow.

HPD30 from '98 Cherokee with 3.55 gears (high ratio carrier, open diff) for $200. I figure another hundo in cost to go get it, a c-note for new ball joints, c-note for bearing set up kit, c-note for used 4.10 gears (or more for new), and maybe $60 or so for new front driveshaft u-joints. Plan to reuse existing unit bearings, axles w/ u-joints, and brakes; but will consider upgrading to the Vanco Ford Explorer based aftermarket brake upgrade kit.

I'm already wishing that I had stepped up to Rubicon spec rear disc brakes... at least.

Might consider a front locker or anti-slip. Maybe a tube reinforcing kit, inner C-gussets, and boxing of the suspension mounts. Anything under about $1500 all in (not including the brake upgrade) and I figure I am still way ahead of any crate axle option.

[KCStudly]

Saturday Karl and I made the run to Carbondale, PA using Larry’s hitch cargo basket on the back of the Escape to pick up the High Pinion Dana 30 axle (HPD30). The plan is to build this axle up with 4.10 gears (matching the new rear gears) and swap it into the TJ once it is complete.

Here’s the freshly picked HPD30 axle assembly. The seller unbolted the upper shock mounts; cut the steering drag link between the box and adjuster; cut thru all of the trailing links; cut the brake lines upstream of the joints on the flex hoses; cut the anti-sway bar end links; and cut thru the panhard (or track) bar.


It’s pretty rusty, especially the brakes, but most of that won’t be reused anyway.



The suspension brackets all have a pretty even scale on them, but the passenger side spring bucket must have had debris settled around the base of the spring, which caused it to rust thru (right behind the little clip that anchors the spring pigtail). While it probably wouldn’t have any ill effects, I will be doing a weld patch here.


On Sunday I hosed everything down liberally with PB Blaster; used a touch of heat from a plumber’s torch here and there; and a breaker bar where needed to remove all of the ancillary items.

I found it incredibly hard to turn the steering knuckles by hand, until turning the passenger side axle shaft a tad. Once the axle u-joint flopped the driver’s side knuckle turned easily, while the passenger side knuckle turned a little more firmly. The passenger side U-joint had a bad cup that was causing the whole assembly to bind hard.

I took the axles and unit bearings out as assemblies by removing the three (3) unit bearing bolts, avoiding the big axle nuts. There is a trick to this: use a 2-1/2 inch long bolt (or, like me, a piece of 1/2 inch round bar), place it between the U-joint loop on the outer axle shaft and the inner ‘C’, and turn the steering wheel. As the bolt (or bar) blocks the turning action and resists being compressed by the leverage from the steering input it will force the axle and unit bearing out of the knuckle. Since my axle was no longer connected to a steering box, I just put a large adjustable wrench over the steering arm of the knuckle and used that for the required leverage. Sorry no pic.

Here are the removed axle assemblies.


A few good whacks with a ball peen hammer in the appropriate locations and the steering knuckles popped free from the ball joints. Here is the axle housing with most all of the external items stripped off.



I think the anti-sway bar “bolts” will have to be pressed out and replaced with the studs from the JKS Quicker Disconnect anti-sway bar end links that I already have installed on the Jeep. I say “bolts” because the factory studs are fully threaded and have a Torx socket head on them, but they are clearly a pressed in stud with splined shank, just like a wheel stud. Not sure why they have a socket head then.

I'll probably leave the upper link bushings in for now to protect the bores from sand blasting, then swap them out afterwards.

One thing that was, and will continue to be, a PITA, is the panhard bar mounting bolt. It goes thru the outer ear of the bracket, thru the panhard bar bushing, thru the inner bulkhead of the bracket, and into a tab nut that is slid up into a blind cavity pinched between the axle tube and rear side of the bracket. Well this area was not easily accessible with the PB Blaster... at least I didn't realize it at first... so when I attempted to remove the bolt it snapped off clean at the shank. That left enough of the threaded portion of the bolt stuck in the tab nut, making it just the wrong combination of dimensions to be able to cleanly pull it out of the opening in the nut cavity. I tried grabbing it with a vise grip and mangling the tab part of the nut to get it to fit out of the hole, but no luck. I'll have to use Karl's little pneumatic recip body saw and vise grip to mangle it enough to get it out. This is just a feature that they use on the factory assembly line to speed assembly; if it had been a standard hex nut I would have had to stick a box wrench up in there to hold the nut from turning and the whole thing would have probably dropped right out. Oh well, it may just get a hex nut at reassembly (if I can manage to get one started on the end of the bolt up in that hole... tape the nut into the box wrench to start).

On Monday I cleaned up around the diff cover, chiseled it off with a putty knife, finding the requisite massive “worm” of gasket sealer that every hack mechanic from here to eternity seems destine to over apply. It had squeezed into the diff cavity to the point where the ring gear had smeared flat ramps into the stuff at the top and bottom where the clearance is slight; just ridiculous. Anyway, I tipped the gear lube out into a catch pan... since there is no drain plug… might add one. Nothing scary to report, just black lube oil with a normal amount of gray silt wear product for a high mileage axle that clearly had a lube change some time in its past.

Next I made sure that the carrier bearing caps already had unique letter markings stamped into them, with corresponding marks stamped into the housing lands, to be sure to get the cap orientation exactly the same on reassembly; then I pulled the carrier out. Carrier bearing shims on the D30 are located between the carrier bearing inner races and the carrier, so I will have to make more setup bearings this time.

The pinion nut didn’t want to come off with the small battery operated impact gun, and, apparently the front U-joints are smaller because the pinion yoke wrench I made for the rear doesn’t fit. I’ll have to modify the bolt pattern on the 1310 side of the wrench by slotting out the bolt holes, though I may be able to get it apart using Karl’s big corded electric impact.

Between now and then I have been researching parts supplies and trying to decide between upgrading to the Vanco Ford Explorer based brake upgrade, or just reusing the TJ disc brakes. I haven’t found any used reverse cut (high pinion) 4.10 gears for sale recently, but am looking at a package deal on new gears with the install kit, which helps a little. There are import versions of these for even less cash, but I want to at least stay with American brand items for these critical parts.

There are a lot of little things that I may or may not be able to reuse or harvest off the TJ, but I want to have as many of these sorted out before I take it back out of service, so most of the little stuff will be new and ready to go before then. The TJ has had the dreaded “death wobble” in varying degrees on and off since we got it. This is caused by tire wear (little cupping on each tread lug) and then the frequency (speed) that causes the tire to try to bounce when the oscillations reach harmony. I have inspected, and have asked various shops, including the dealer, to inspect the front end, and none of us have ever found a smoking gun. Unit bearings are good, tie rod ends are good, ball joints good, steering box good, trailing arm bushings look okay, replaced the steering dampener and shock absorbers. I get about 2 years on a set of tires, with tread left, before it returns. Kind of expensive. During wheel alignment the tech has commented that the caster is at the low end of the spec, which is likely a result of the bargain basement 1-3/4 inch spacer lift.

So this time I’m probably just going to replace it all, except the steering box… although I will inspect it and its mounting well.

Here’s another thing that my research has turned up. The TJ caster/pinion angle adjustment is via cam washers at the lower trailing link mounts on the axle. The XJ adjustment is via cam washers at the lower link mount on the chassis. Therefore, with this swap there is no built in method of adjustment, unless you go with aftermarket (or homemade) adjustable lower link arms. This correlates to correcting the above noted lack of caster, which may be contributing to the tire wear. I can buy entry level Terflex brand adjustable arms from Quadratec, which supposedly offer more flex, but they do it by allowing the adjustment thread to pivot, essentially becoming a wear point… which I don’t like. Yeah, you can grease then frequently, but I would prefer less vehicle maintenance, not more. And the polyurethane bushings, while probably good for holding alignment and long wear life, wouldn’t do anything good for ride harshness and noise transmission.

What I am considering doing is recreating the factory adjusters on the XJ axle. If I bias the location of the slots and ‘C’ tabs surrounding the cam washers, I should be able to provide for more caster using the stock link arms with new rubber bushings. I’ll take some pics the next time I’m out at the shop.

Since I haven’t pulled the trigger on parts yet, I have time this holiday weekend to go back and correct the rear shock mounts; investigate the parking brake issue further, and reinstall the rear anti-sway bar.

Also, once the front housing is stripped down bare, degreased and temporarily plugged up, I will sand blast it to remove rust so I can get a better idea of the condition, fix that spring perch, get a preservative coat of paint on it, and not have to worry about debris contaminating the reassembly process.

Anyway, it may have been easier just to buy a new Jeep! But once complete she will be better off and on road, as well as while towing.

[KCStudly]

Happy thanksgiving to all of my internet friends. All of you. We had a great late lunch celebration at my sister and brother in-law’s place. Slow roast turkey; a really nice dressing with squash, breading, dried cranberry, and pecans; corn niblets; fresh seasoned bread with butter; traditional green beans with mushroom soup gravy and fried onions; and acorn squash quarters roasted with a bit of seasoning. For starters Yvette made a nice veggie platter with baby carrots, broccoli, colored bell peppers, and herb garnish from our front step (thyme, mint, and rosemary); and there was shrimp with cocktail sauce (meh… store bought). Also on tap was regular “stove top stuffing” (meh), gravy (from a jar…meh), and store bought dinner rolls. My BIL Rene made his traditional pork pie (yum).

For dessert there was a pistachio fluff pudding pie by Ellen (yum), Madeline made pumpkin fluff filled eclairs (subtle, but yum), Rene made carrot sheet cake with cream cheese frosting (with pineapple and coconut added… yum), Ellen made pumpkin pie cookie bars (yum), and Maranda made banana bread (yum).

Then, later in the evening we went to my mom and Bill’s place for thanksgiving dinner. Another roast turkey (that I carved… yum); cornbread stuffing; pan gravy; a mixture of squash and Brussel sprouts with dried cranberries and pecans; and slow cooked cranberry sauce that Chris made in the crockpot.


For dessert mom made a delicious, moist, soft, pumpkin pie in her signature flaky crust, and two (2) pecan pies with freshly whipped cream. Nough said.

That was yesterday. Today I took it easy this morning on holiday (had leftover pecan pie for breakfast) and spent a half day this afternoon on the axle. I dragged out some parts for the D30 that I had bought way back when we first bought the Jeep; including the 3.73 and up open carrier, a set of Superior Alloy 27 spline axles, and a forgotten diff setup bearing set for a TJ D30 (with short pinion and crush sleeve, vs. long pinion… I think… and no crush sleeve); despite the fact that last night I went ahead and ordered a high pinion 4.10 gear and set up bearing set with XJ set up kit… some redundancy.

When digging thru the box that the high range carrier came in I found a new in package set of ring gear bolts, a diff cover gasket, a selection of carrier bearing shims, and a new roll pin for the spider gear cross shaft, all forgotten finds; again, some more redundancy. Somehow I had lost track thinking that the setup kit was for the D35. I had bought it having been represented as “new” and yet it had been rifled thru with loose items busted out of the plastic film packaging. So I can either flip it as is, or, since it doesn’t look like I will be able to harvest the old carrier bearings w/o damaging them, use the bearings therein to make my own setup bearings and eat the rest of the duplication as “spares”.

Once I made it to the shop today I found Karl with a new to him lathe on the trailer trying to off load. I jumped in and helped get it off loaded (we make a good rigging team with me running ground crew and him as operator). It is a decent upgrade to his current lathe, with a quick collet head stock, much better tailstock, change gears, and better coolant system. However, the capacity is about the same. Also, after fiddling a bit, he found that his current 5 hp 3 phase “whompenstien” phase converter is under powered and won’t run its 5hp motor. Oofdah. But it is still an upgrade for a very reasonable price. Eventually, with the existing “flux capacitor” running and the mill running off of that (to create a bit more “momentum” on the 3 phase circuit) the lathe would start and run. Kooky Y phase start and delta run motor spec, but ended up being a simple 220 delta 3 phase set up.

While Karl was sorting thru that, I pressed the anti-sway bar studs out of the axle link brackets. At first I tried using one of the larger adjustable clamps, but it just didn’t have the ‘nut’ required. I ended up using this heavy duty ‘C’-clamp with a 1 inch impact socket spacer. The clamp alone wasn’t enough, but once I loaded it up pretty hard, a few raps on the nose of the clamp with a ball peen hammer busted the stud loose. You can see the setup in the first pic and a better close-up view with the other side stud already popped out in the foreground.



Here’s a shot taken under the TJ (at a crude angle) of the lower trailing link and cam washer bolt caster/pinion angle adjuster mentioned in my previous post. Notice how the washer adjustment is fully engaged pushing the bottom of the axle as far forward as possible. The ‘C’ or ‘n’ shaped tab that is spot welded onto the lower mount bracket is replicated on both sides, with the same eccentric washer on each side.


While appearing in rough used shape here, the JKS Quicker Disconnect anti-sway bar link replacement stud can be seen here. It fits thru the same stud hole in the anti-sway bar bracket with a shouldered stud, securing nut, and quick pin retainer that allow the links to be disconnected, pivoting the anti-sway bar out of the way and fixing the links to dummy mounts located up on the frame, so that when off road the front suspension can articulate more freely over rough terrain.


Here, by comparison to the TJ adjuster, is the XJ lower link mount. No slotted hole and no eccentric washer tabs. (The lower link bracket is straddling the steel tubular saw horse in this pic, not to confuse.)


If I slot these holes and weld on fabricated C’s (or “n’s”), I can recreate the factory adjustment. By biasing the slot and tabs forward, I can gain caster adjustment.

Once I rolled the axle housing upside down I was able to fish out the broken panhard bar bolt and tab nut just by grabbing it with the vise grip pliers and seeing which way to pry it out.


I used a scrap piece of 1-1/2 inch tube (that Karl uses for hand rails) to knock the old inner axle seals out (er… actually in toward the carrier housing).



Here’s the passenger side before popping the inner axle seal out. Note the orange bead of sealant around the tube to diff housing casting joint. Despite being dirty on the top (axle upside down in this pic), this bead was machine like uniform except where it returned on itself; leading us to believe that it was factory applied when the axle tube was pressed into the housing. The same orange colored sealant was evident in the curious blind holes in the gasket face of the diff opening, over the tubes in between cover bolts.


Trying to avoid contamination of grease and debris in the sandblast cabinet, and vice versa, I shaved the gasket surface using a razor blade scrapper tool and wire brush; dug the excess sealant out of the cover bolt holes preparing to reseal the cover in place; scraped excess crud from around the ball joints and everywhere obvious; chiseled some heavily rusted flakes off; and generally made preparations to sandblast. I used the big corded impact gun to loosen the pinion nut, but decided to snug it back up and leave the 3.55 pinion in place as a plug while sand blasting. I’ll clean up the diff cover and reseal it to the housing prior to blasting.

I will also make some wooden plugs for the axle tube ends and secure those in place with a length of threaded rod strung thru the axle tubes to keep blasting grit out of the center housing.

Also spent some time dragging scrap parts out to Karl’s new tipping dumpster, and removing the old D35 out of the shop. Salvaged a length of the old rubber vent tube to protect and seal the plastic vent tube bulkhead during blasting.

Tomorrow? I’m sure there is plenty of stuff to do, even if it means going into the plant on a holiday weekend.