Subframe is Bent - but just a little

[vjaneczko]

So progress has been quite slow on getting Big Red back on the road (weather, business travel, laziness, etc.), but we’re quite close. Dr. Brutal is concerned about the subframe having gotten bent in the accident, causing alignment problems.

Subframe - slight bend

From the (poor cell phone) image, you can see the bottom of the frame and a slight ‘wave’ in the metal running across the hole in the bottom of the frame - it should be a perfect circle. When he was inside the wheel well, he pulled the control arm off. The rear bolt was actually curved because of the impact. It was slight but enough to cause a challenge in getting the bolt out. I’ve not spent a tremendous amount of time inspecting the subframe for more damage, but I’m hoping I can just replace the bolt that was bent and be on my way.

My concern is that it may be unnecessary to swap the subframe. I have one on the parts car so it’s not a problem getting one, but I’d like to avoid the time & effort involved with getting an engine lift – actually two lifts, right? – and swap the frame and all the little bits involved. So I guess the bottom-line question is this; if there’s any damage to the subframe, no matter how slight, should it be replaced?

[cn90]

No worry from the picture.

Many years ago I hit a big flat rock (icy day), it created a 5-mm dent in the middle of the subframe (just inner of the oil filter area) and yet no alignment issues.
Just button the car together and align it and see what happens.
If necessary you can adjust the camber on the front a bit.
That kind of damage probably won't change the caster at all.

So don't worry!

[xHeart]

I had the hardest time putting the center bracket nut at the steering rack installation. There is a bent right at the center, see the photo.

I couldn't put a socket to the nut there, hence used 17mm open-end wrench to loosen using rubber mallet, and later tighten, then used angle to determine the torque, like cn90 often tells us.

Previously, I had shown it to a local maestro, who said, it wouldn't change a thing.

Steering rack center bracket

[Kingsford]

I have a spare one if you come to England to pick it up lol Its not a great deal of a damage to effect the alignment.

[anmartin44]

if you do replace it, it's not super hard if you have a cherry picker. mainly just the four subframe bolts and then unbolt the steering rack, control arms, swaybar endlinks and mounts and drops right down with a couple jacks. i was able to take it off by myself but you'll need two people to remount.

[vjaneczko]

Without Googling this (yup; lazy), are the control bolts supposed to be one-time use? I may leave the subframe in place and just replace the bent bolt with an old one from the parts car.

Oh, and I got something else from IPD;


Anyone care to theorize if the impact may have bent the four bolts attaching the subframe to the frame? If they're bent, I should probably order new ones in order to get the Poly Subframe Bushing Inserts installed.

[Ben850]

I installed these and re-used the original bolts. I am not sure to what degree, if any, my subframe was tweaked by my accident. I believe my accident had greater impact force than yours as my airbags deployed. The bolts were not effected at all.

I actually had to straighten the unibody a bit. But after everything was bolted back together, I have not even taken it for an alignment and there are no steering issues at all.
I installed the poly shims a few months after it was back on the road and there was only one subframe bushing that was slightly compressed. I figured the shims would tighten things back up.

A side note: I used a tin snip to trim the top edges of the shims to more of a point. That and the grease helped the tighter ones into place.

[vjaneczko]

Trimming the inserts - good idea. I've seen a few posts on SwedeSpeed indicating they're tough to install.