Brake rotor warping/judder in the Tow Vehicle

[Shadow Catcher]

“Brake warpingâ€

[mikeschn]

I had semi-metallic brake deposits on my rotors. So when I had them turned I switched to ceramic pads. My brakes have been shudder free for 20,000 miles now!

Mike...

[caseydog]

Been there, done that, got the headaches.

I don't do this on my street cars, but on my track cars, I always had to bed my brakes really well when I replaced rotors, or risk vibration after a track session. That lays a nice even layer of pad material on the rotors. That "film" of pad material is crucial to the performance of disc brakes.

I don't turn my rotors on my cars when I replace pads. Even on my track cars. I change pads, measure the rotors, and move on until the rotors need replacing. The pads conform to the wear on the rotors pretty quickly, and I have never had a problem caused by not turning the rotors. And, my "film" of pad material is already on the rotors.

One thing that a lot of people neglect, especially here in the heat of Texas, is to flush their brake fluid as recommended. But that's another subject.

BTW, I have used PowerSlots on my track cars with good results. I get them through TireRack. And, if you want to go to the trouble of "bedding" your new rotors, TireRack has a good description of the process here...

http://www.tirerack.com/brakes/tech/tec ... ?techid=85

CD

[Shadow Catcher]

What happens
http://www.youtube.com/watch?v=ZaSL03K3bg4
results, maybe
http://www.youtube.com/watch?v=xmW9c-7KCqA
to a certain extent you get what you pay for, hopefully!
The engineering on the holes is suspect. note that the first set of rotors had slots bu no cross drilled holes.

[eamarquardt]

I had severe brake shudder on my Ford Windstar Van. Had the rotors turned and problem returned in short order. Replaced rotors (new, China's finest) but not pucks. Fine for the past year or more. I agree that turning the rotors as a general practice just to get a nice smooth surface when replacing the pucks is not required. On the Navy jets I trained in, they didn't turn, blanchard grind, etc when they changed the pucks. If that's good enough for a 140 knot landing, it ought to be good enough for the speeds I travel in my van.

There you have it (again), the world according to Gus.

Cheers,

Gus

[bve]

On Jeeps the shudder has been known to extend beyond braking. I just replaced the front rotors yesterday and have said good-bye to what is referred to as 'death wobble'. Very scary experience when your front end starts to go into convulsions so strong you think you are going to lose control. Diagnosing the cause can be problematic from what I read - I got lucky by catching it on the first go.

In my case it would start to happen at about 82km/hr (50m/hr -if my conversion is correct?) and the only way to bring it under control was to speed up beyond 90km/hr or slow down, at this point application of the brake was not an option to slow down, easing off the accelerator was the only choice.

These two videos depict it VERY well.

Same generation as my TJ. Looking at the dash it shows the Jeep has 26,000 miles on it mine has about 87,000 miles.
http://www.youtube.com/watch?v=vqVkG2Lp4r4&feature=related

This is the latest generation and it is STILL a problem.
http://www.youtube.com/watch?v=vwiv23dLhMY&feature=related

I can't speak to the cause of the DW in the 2 videos, however in my case it seems it was in fact what has been referred to as 'warped' rotors.

[eamarquardt]

My 1967 vw also exhibited a tendancy to shudder like your jeep (at intermediate speeds). It had a steering damper (like a shock absorber) mounted to the tie rod connection (as I remember). Every time I had a problem, replacing the steering damper solved it (you could feel that the damper was weak). I've seen aftermarket dampers put on with ubolts so maybe a aftermarket damper would solve or reduce the problem.

Hope this helps.

Gus

[asianflava]

Hondas are notorious for warped rotors, I put a set of Powerslots on my 89 Civic and that pretty much ended that. There is and probably always will be disagreements on which is better, slots or holes.

Interestingly, I was talking to a powerslot rep at some show. He said that one of the biggest causes of warping is slowing down for a stop light, and sitting there with your foot on the brake pedal. All the heat generated by coming to a stop is concentrated at one spot on the rotor. That is why auotmatic transmission cars seem to warp rotors worse than manuals. He suggested to either take your foot off the brake or stop early and creep a little while waiting.

[ajricher]

On the partial hijack discussing "death wobble":

Land-Rover products are noted for it, from the earliest ones on through the RR Classic and Disco 1. After that they messed up the front-end hardware and the problem went with the lower quality...

What you are getting there is an unordered oscillation caused by insufficient damping in the system. If you have a damper, replace it. If not, you need to examine both your front-end geometry (is this Jeep lifted a lot?) and the condition of your front-end components. Were this a Landy I'd be examining the steering damper (if it has any unloaded play scrap it) and the upper and lower bearings in the swivel housing for condition their preload - your knuckle joints are the equivalent, I believe.

I know this problem very, very well...fought it on just about every LR I've ever owned. It's simple to kill when you know the cause.

Just my two cents' worth - Alan

[caseydog]

Hondas are notorious for warped rotors, I put a set of Powerslots on my 89 Civic and that pretty much ended that. There is and probably always will be disagreements on which is better, slots or holes.

Interestingly, I was talking to a powerslot rep at some show. He said that one of the biggest causes of warping is slowing down for a stop light, and sitting there with your foot on the brake pedal. All the heat generated by coming to a stop is concentrated at one spot on the rotor. That is why auotmatic transmission cars seem to warp rotors worse than manuals. He suggested to either take your foot off the brake or stop early and creep a little while waiting.

I went with the Powerslots since my 2,400 pound car didn't require even that, let alone cross-drilled rotors. My car was a "momentum" car on the track -- lightweight with moderate power. The idea was to enter the corners as fast as possible as opposed to braking late and hard, entering slow and powering out, like the heavier, more powerful cars do.

I had Powerslots, and used Hawk pads. No problems.

CD

[john curtis]

Have a 2006 F150 and been having the same problem with warping.Took it in for new pads and a turning yesterday and by the time it was done we replaced all 4 rotors and front pads with new seramic.The cheap pads that Ford uses wear the rotors down so thin that there isnt anything left to turn.The back pads are still at 60% but that is were the warping had occured and to turn them down there wasnt enough metal left to last six months. $900.00 later.

[caseydog]

Have a 2006 F150 and been having the same problem with warping.Took it in for new pads and a turning yesterday and by the time it was done we replaced all 4 rotors and front pads with new seramic.The cheap pads that Ford uses wear the rotors down so thin that there isnt anything left to turn.The back pads are still at 60% but that is were the warping had occured and to turn them down there wasnt enough metal left to last six months. $900.00 later.

Did you examine the calipers to make sure the pistons move freely? I had a GMC Jimmy that would eat pads and rotors due to poorly made calipers. The pistons would start to seize up over time, causing the pads to be slightly gripping the rotors even with the brakes off. I had to free up the pistons every 6,000 or so, until GMC finally fixed the problem.

BTW, mine was one of the first 1995 Jimmys off the assembly line -- never buy the first of a new GM model, unless you like being a product tester.

CD

[teardrop_focus]

Interesting reading...

The "Warped" Brake Disc and Other Myths of the Braking System

Caseydog

I don't do this on my street cars, but on my track cars, I always had to bed my brakes really well when I replaced rotors, or risk vibration after a track session. That lays a nice even layer of pad material on the rotors. That "film" of pad material is crucial to the performance of disc brakes.

Using Caseydog's brake pad friction material transfer onto the brake disc/rotor as an example, it is the uneven distrubution of pad material that are the source of the high spots that create brake pedal "judder".

This is usually caused, as the above-linked article states, by leaving one's foot on the brake pedal after a long, hard stop, leaving a pad imprint on the rotor.

Anyway, I'm not saying anyone's right or wrong; merely posting additional info as food for thought.





More here: http://www.stoptech.com/tech_info/tech_ ... pers.shtml

[Mightydog]

+1 for teardrop_focus's post.

I had the exact same 'warping' problem with my Suzuki Vitara. The first thing the service manager asked me to do was to describe how I sit at a stop light...

"Huh?"

"When you sit at a stop sign or light, where is your foot?"

"On the brake pedal pushing hard so if another car slams into the back of me, I don't get pushed into traffic."

He explained the situation that teardrop_focus did in the post above. After replacing the rotors with dimpled/slotted rotors, he recommended coming up to a stop slowly and letting off the brake, then applying the brake slowly as you stop. Get your slowing down done early so you're coasting into place with little braking. When you get almost to where you want to stop, slow down all the way...then slowly move to the final stopping place.

Heat builds up in the rotor and pads. If you're able, move the rotor under the pads so a cooler part of the rotor comes into contact with the pads cooling them. After you have everything cooled down as much as possible, keep your foot on the brake, but not in a death grip. If you get hit from behind, chances are your foot will come off the brake anyway.

Yeah, my dad taught me to push hard on the brake will at a stop. It is true that my foot will probably come off the brake if I'm hit from behind. Sorry dad.

[Arne]

When doing my limited brake jobs, I don't get the rotors turned unless there is a shudder/jutter... as mentioned, the pucks conform quickly, and a turned rotor is thinner and more likely to cause a problem in the future..

If the rotor is significantly screwed up, replace them.