Should I patch or replace ?

[Muggnz]

As expected, after stripping the wooden deck off my donor trailer. I've discovered some rust.

The serious stuff is on the outside & inside of the front cross member. Whilst I cannot see inside. I have proved with a garden hose, that water goes in & not as much comes out. Tomorrow I intend to drill a couple of holes in the bottom to to correct that.


The front portion of the trailer.


Note the crack right it's a PITA


Would this bar be strong enough ( if it was better welded ) to bring the strength up to what existed originally? The metal thickness looks to be almost 2mm.


Note the hole in a most inconvenient place.


The trailer, with supervisor in the background.


I'm wondering if I can get away with patching up the holes? Or do I have to replace the entire member?


TIA
David

[angib]

I'd say what matters is the three bits of the tongue and the three front-to-back rails they connect to - these are the strength-critical bits. Check underneath where the two angle tongue members meet the two side rails - any cracking there is dead serious.

But the cross-members such as the front one are a lot less important, unless you're going to fit a really heavy body. I think your repair piece is all that's needed - if it were me, I'd be tempted to not even bother repairing that front cross-member.

Andrew

[ChickenFoot]

If if were me and for peace of mind I would cut it out. It should a straight forward remove and replace.

[Dale M.]

With what already looks like a "patch" previous owner was suspicious of front cross member....

I would consider replacing it...... For the few dollars for material and labor (welding) it would be worth a lot more for the peace of mind...

Besides the embarrassment of having front area crumple would be a good YOU TUBE video.... Just kidding...

Dale

[Alphacarina]

Even without the rust, I'm not wild about the way the three members of the tongue were butt welded on the front crossmember - If the crossmember were 100% rust free, that's still not a good way to do things because it makes the strength of the tongue dependant on the strength of the box section of the front cross member - Put the coupler on a block and jump up and down on the front crossmember and picture how the load is trying to deform that box section. With that crossmember rusted out as it is, the integrity of your tongue is nil

I would replace the crossmember and toss out the 3 pieces of the tongue. Replace them with 2 pieces in a Vee (with the coupler at it's intersection) which goes under the new front crossmember a foot or so from either end and run back to the main fore and aft members on either side, welded under those frame members. That way, your tongue isn't dependant on the quality of the welds at the front cross member, or how strong a box section it is, since they are one piece and run from the side rails, under the front all the way to the coupler

Don

[Muggnz]

Don,

I'm not wild about the design either. But it has worked since 1973 when it was built. And it does reduce the height, which is important to me. As I'll be towing it behind my Corolla.

After finding a hole partly hidden by the black paint, and all the other issues. I will be replacing the cross member. As can be seen, the tongue isn't totally but welded.

I'd rather stick with what I've got & get the patches & new cross member properly welded in. Of course I will regret it, if it features on youtube. I guess I'd better re-visit http://www.angib.pwp.blueyonder.co.uk/t ... tear84.htm to make sure it'll be OK.

This also needs better welding.



Andrew,

I haven't seen any cracks where the two angle tongue members meet the two side rails. Which doesn't mean there aren't any, just that I haven't seen them. Is there anything that can be done ( easily? ) to strengthen "where the two angle tongue members meet the two side rails"?

Currently the trailer weighs 194kg. And once I remove the light clusters & all the pillars except those directly behind the wheels. I expect it to be close to 180kg. I don't need or want a heavy weight kitchen or aircon etc. I'm aiming for my version of a lightweight full width generic benroy. And haven't done any weight calcs for the finished product, yet. I'm hoping to be under 500kg all up.

[bobhenry]

I am suprised no one mentioned triangular plate steel gussetts. I think they would add a great deal of strength with very little weight cost.
I have to agree with don a couple square tubes ran under the center tongue and angled back to the second crossmember would take the strain off of the tongue welds and add a safety factor. I can see nothing worse than being 200 miles from home and having a tongue failure.

[Muggnz]

bobhenry,

thanks for the great idea.

[Alphacarina]

I'm not wild about the design either. But it has worked since 1973 when it was built. And it does reduce the height, which is important to me. As I'll be towing it behind my Corolla

Just because it's always worked doesn't mean it's safe - The Challenger fell out of the sky because 'it's always worked, so why change things' - The 'O' rings were thought to be OK, because they had always worked before . . . . even though they were a major safety concern in many of the engineers minds . . . .

Looking at the ground clearance at the axle, I would think putting the tongue under the front crossmember would be a benefit for a small car and it would probably make the trailer sit more level, front to back than it does now. Hook it to your Corolla and mearure how far the 4 corners of your frame are off the ground - Likely your back end is high and your front end is low and if so, putting the tongue under would level it out some

Don

[Muggnz]

Here's what I did today.

I've removed most of the front cross member. What's left is going to stay in place.

More rust to patch. I plan on welding extra long patches on both sides, as the other side is similar. Covering the whole height of the beam.


The trailer is mostly level.

This is the central tongue beam. The rearmost portion of the trailer is about ( judging by the height of the level above the beam when placed behind the front cross member ) 6 or 7 mm higher.

Sorry, I forgot to measure it.

Whatever I end up doing with the tongue, I will be keeping the centre member, as I feel that it adds significantly to the strength of the tongue.

[angib]

David,

I'd say you have bared enough of the original tongue members to show that there's no cracking present. I'd be looking for vertical cracks in the shallow section under the cross-member, and it doesn't look like there's any.

The "extra long patches on either side" will reinforce that area well.

If you aren't going to add back the same design of cross-member, you must weld a patch across the gap in the top of each tongue/rail where the cross-member used to be - you may say that's obvious, but I've mentioned it just to be sure!

Andrew

[Muggnz]

Andrew,

I was going to weld patches over the top of each rail. After drilling holes in the bottom of what's left of the old cross members. So that if water does get in, it can get out easily.

I've never minded people mentioning the obvious, as there are times when one cannot see the trees for the wood. Me included. And what might be obvious to you may not be to me.

What I am have difficulty with, is deciding how to re-enforce the area where the tongue meets the 2 outside rails. What's there may be strong enough. But I'd feel a lot happier with extra correctly placed metal. How it looks is not important. As I expect to be able to hide most of it with a tongue box

One idea is to use the same patching method. Another is another set of beams from the center rail, welded to the angled tongue braces on the top outside corner. So that they run underneath the centre & outside rails. In other words these new braces will be positioned like those in your Composite Tongue diagram.

The existing rails & braces are all 1.5" x 2.5" x 1/8" .


Don,

I've decided that measuring will probably be a waist of time. The driveway isn't smooth or flat enough for accurate results.

David