Is my trailing arm bent??

[Panici]

The bores should line up right?

Old thread, but yes.
My blue snow brush handle happened to be the exact right diameter with no slop.

Both my trailing arms lined up perfectly. I was checking after welding in reinforcements after the suggestion by econti in my build thread.

POR15 on mine not powdercoat just FYI.

[adamnur]

I have the same issue....i've seen this happen to a few people after powder coat but that might just be coincidence-- never seen an update.

My arms and subframe are freshly pc, using factory bushings and it's off by the same sort of margin.

[Shifty_K]

Yeah it’s a weird on for sure.

The trailing arms measure 11” and 11-1/16th” wide between the edges of the inner bores.

Im thinking the most cost effective trial is oem bushings and see if that works. Otherwise I’ll get some used ones, measure, dry fit and redo the powder coating 🫠.

[moatilliatta]

Interesting! I would "assume" that they shouldn't be bend outward.. I've never checked the trailing arms l like that. Good call.

Ill try and check if I got some trailing arms laying around without bushings.

Are both trailing arm bushing widths the same?


Its a sign not to use garbagistic bushings!

[Shifty_K]

I ordered some 12mm rod to check the subframe this week.

I got a piece of pipe to check the bushing bores in the arms and it looks like they are bent outward. There is about 2mm difference in width between the arms and the pipe does not slide through both bores on either arm, both appear to be twisted in the same direction.


I it seems unlikely or coincidental that they would both be spread pretty close to the same distance and twist almost identical.



The bores should line up right?

[moatilliatta]

Reference

https://www.r3vlimited.com/board/forum/general-forums/members-rides/the-project-forum/382742-entropy-e30-hiatus-cont-more-seeing-less-wrenching?p=9971386#post9971386

[moatilliatta]

I think I'm seeing those big V / U shaped reinforcements causing warpage on trailing arms when people weld them in. Mcmaster car has M12 rod.

I'm not beliving that powder coating ovens warp suspension parts, maybe some wild powder theyre using.

[Shifty_K]

Thanks for replying.

I get what you're saying but both arms appear to be out the same amount and with the gusseting on the mould of the arm it seems unlikely they'd warp from a powder coat oven, I'll take some measurements tomorrow and see if I can figure it out.

I reinstalled both bushings with the thick collar on the inside and can get it installed but the last bolt holes are still off about 1/8th of inch, seems like it might go if I reposition the subframe and arm so I can maneuver better.

[moatilliatta]

You can take your subframe out and set it on a level table. Bridge the right side mountings point with a m12 rod, repeat on the left. You can now measure the subframe mounting points angles.

A lot of work. but you can rule it out..

[Shifty_K]

What ended up being the cause? I am having the exact problem.

[turner.e30]

Looking at that picture, have you tried dropping the arm in from the top versus in from the rear? Those tabs appear to be on a bit of an angle (pictures are tough to judge) and coming in from the top MAY make a difference.

I doubt if the powder coat heat had an effect. It may however added a mil or two to the thickness of those tabs???

I did try that, yes. No luck.

Looking at it, it seems that if I reversed the bushings it may fit. Anyone know if this would have any major consequences as far as alignment is concerned?

[tomstin]

Looking at that picture, have you tried dropping the arm in from the top versus in from the rear? Those tabs appear to be on a bit of an angle (pictures are tough to judge) and coming in from the top MAY make a difference.

I doubt if the powder coat heat had an effect. It may however added a mil or two to the thickness of those tabs???

[Vincenze]

You can use the threaded rod tool to expand it.
Or is it too wide? Then the threaded rod tool should be able to compress it too.

You may try regular rubber bushings as they are more forgiving.

[turner.e30]

If it was bent you would think you would see some damage or a crimp somewhere on the TA where the bend occurred. This is very odd. I am in the process of refurbing my rear suspension and subframe and used the same method to remove the TA bushings and no way could you bend the TA using the threaded rod method. The rod would bend or break before the TA would bend.

Did you talk to the powder coater? They use alot of heat to perform powder coating, maybe something happened to the TA when it was heated that bent it? Longshot but hard to come up with any other explanation.....

Agreed. I looked it over pretty carefully and couldn't find anything obvious. I did ask the powdercoater and they didn't seem to think the process could have caused any damage, and I agree with them. It's baked at 400 degrees which I wouldn't think would affect anything.

I'm going to take it around to a couple other shops to see if anyone would make an attempt at straightening it out. The first shop I took it to wouldn't touch it because they were worried about it collapsing under pressure.

[E30andy]

If it was bent you would think you would see some damage or a crimp somewhere on the TA where the bend occurred. This is very odd. I am in the process of refurbing my rear suspension and subframe and used the same method to remove the TA bushings and no way could you bend the TA using the threaded rod method. The rod would bend or break before the TA would bend.

Did you talk to the powder coater? They use alot of heat to perform powder coating, maybe something happened to the TA when it was heated that bent it? Longshot but hard to come up with any other explanation.....