Bolt Breaking Off in the Trailing Arm?

Buckterrier · 10-26-2008, 02:19 PM

Howdy guys, Went for a drive this afternoon and when I got off the exit the car felt funny. hit a small bump and heard the tire hiting the wheel well. I limped home and looked under the car. The right rear shock was just hanging there. I got the car into the gagrage, took the tire off the car and jacked her up. The shock bolt snapped off IN the trailing arm. Anyone ever hear of this?? Is it a common thing to happen? Being the rookie I am I wouldn't think so. Is there a fix other than a new trailing arm?
Thanks in advance for any advice.

barney911rs · barney911rs's Garage

WOW, that's a big bolt to snap off. Never seen one myself. I would imagine that it could be drilled out. Just need to make sure you don't mess with the aluminum threads. You should not have to replace the trailing arm. If one broke, I'd replace both just to be safe. Hopefully someone else has experience with this.

84_Carrera · 10-26-2008, 02:46 PM

Looks like Mark's "That Guy" that broke his suspension...

Seriously though Mark, I have heat, drills, and easy-outs galore at the house here. I'll confirm swinging through on Wed. PM... I'll even bring the Sam's Light, you provide the Brats & we'll deal with it. With the car up on stands, get the other bolt as a template & hit Fastenal, or Pelican etc. & get one in, we'll get her back on the road.

911pcars · 10-26-2008, 02:46 PM

The aluminum trailing arm has a steel thread insert for the shock bolt (a few mm below the mount surface). At this point, it's a steel thread and steel bolt. If there's corrosion in that area (probably the reason why the bolt failed), I'd try soaking it in Kroil or equivalent. Try the usually broken thread extraction methods (drill concentric pilot hole, left hand drill, etc. ). Heat might be good since that will expand the aluminum a bit.

If you're lucky, the PO might have lubed the threads with antiseize.

Hope this helps,

Sherwood

porschenut · 10-26-2008, 03:08 PM

Most likely what happened is that the bolt was loose and backed out far enough to fail under the sheering stress. Just yesterday I replaced both rear shocks on my car, and I found the left side bolt overtorqued, and the right side one barely torqued at all. In time it surely would have worked itself loose.

Buckterrier · 10-26-2008, 03:28 PM

Thanks guys, and especially Fred. Will let you know the outcome, (I don't like being 'that' guy').

Shaun @ Tru6 · 10-26-2008, 05:35 PM

Mark, send me your address, I'll send you a good bolt.

SteveinTO · 10-26-2008, 08:48 PM

If it's not broken down too deep, try tapping it with a chisel or punch and "walk" it around and out. Never works for me, but maybe you'll get lucky.

barney911rs · barney911rs's Garage

Sherwood,

Thanks for the info about the steel sleeve. As Johnny Carson used to say "I did not know that"

Alan L · Alan L's Garage

It is basically a regular metric high tensile bolt. I recently replaced my originals with a stock industrial bolt which was about 1 mm shorter. Mine seemed to be bottoming out in the hole without coming hard up on the shock.
If it had worked a bit free before breaking you should have had an annoyong rear clunk everytime you went over a bump (like mine used to). This is the shock sliding on the bolt - even a mm will be enough for that.
But it should be extractable without removing the arm, with a bit of luck, beers and @#** words. Will depend a bit how long it has been since last moved. If you can soak it, do so, but not sure how you may do that. Heat would be my option - works wonders (oxy/acetylene). Then depends on how much of it you can get at. If it was hard to get at (slightly recessed) and easy- outs won't work, you could consider welding a smaller bolt head to it, heat and hope.
Alan

Dixie · Dixie's Garage

Don't rule out that some PO replaced the bolt with a weak grade-1 bolt. hopefully the remnants will come out without too much fuss.

Buckterrier · 10-27-2008, 05:33 PM

Quote:

Originally Posted by Alan L

It is basically a regular metric high tensile bolt. I recently replaced my originals with a stock industrial bolt which was about 1 mm shorter. Mine seemed to be bottoming out in the hole without coming hard up on the shock.
If it had worked a bit free before breaking you should have had an annoyong rear clunk everytime you went over a bump (like mine used to). This is the shock sliding on the bolt - even a mm will be enough for that.
But it should be extractable without removing the arm, with a bit of luck, beers and @#** words. Will depend a bit how long it has been since last moved. If you can soak it, do so, but not sure how you may do that. Heat would be my option - works wonders (oxy/acetylene). Then depends on how much of it you can get at. If it was hard to get at (slightly recessed) and easy- outs won't work, you could consider welding a smaller bolt head to it, heat and hope.
Alan

WOW, it did have a 'clunk'. I just thought it was a noise that was part of the car going over bumps. And it was coming from the side that broke. I had the car lowered and some suspension work done on the car in June so I figured nothing could be wrong with it. Well if all goes well Wed. it will come out easily and I won't have a clink anymore

Buckterrier · 10-30-2008, 06:31 AM

It wasn't for lack of trying but we, (Fred), weren't able to get the broken stud out. So as all good car guys do we did three things.... Cooked brats on the grill, drank beer, and went to Juicys. I think the name says it all. Unfortunately this is the best arse we saw all night...

And then this morning...

Off to Dan Jacobs. She'll be in good hands in no time. Special thanks to Fred, (especially since he left his Flying Lizards hat. Isn't possession 9/10th's of the law?

), and to Shaun for donating bolts. I'll get then back to you.
We'll see what the damages are. To be continued...

84_Carrera · 10-30-2008, 08:05 AM

The bolt had definitely backed out some before shearing. You could see thread marks imprinted on the (assumed) smooth / unthreaded portion of the sleeve.

I didn't have access to Oxy/Acetylene, just a portable MAPP torch.

I was able to drill out to the point of using the largest easy-out I had (any larger would have required going all the way to drill / re-tap, and the largest tap I had on me was an M12. So, sorry & thanks for the Brats Mark. It was a pleasure visting with you. Yeah, my eyes are still stinging from Juicee's. We were like moths to the bug zapper... "Don't go to Juicee's...", and yet, there was an irresistable pull toward the light (or dark, in this case).

As for the Lizard cap, no biggie. I wore the knit one I got at the same time this morning... the birdbath was frozen over, so I'll give it about 34 degrees when I left the house. Top down, of course.

304065 · 10-30-2008, 09:41 AM

Dan J is a good man, he will fix you up in no time.

Shaun @ Tru6 · 10-30-2008, 11:09 AM

Sorry to hear it Mark, but why send them back? give them to Dan.

Buckterrier · 10-30-2008, 05:21 PM

Quote:

Originally Posted by john_cramer

Dan J is a good man, he will fix you up in no time.

Boy is that an understandment! I think it took longer to have the car towed there than the work. It was ready at 2:00. Have her back safe and snug in the garage...and not more clunk. It's awesome to have a shop like Dan's around. Even though it's 77 miles from my house to his shop. Well worth the trip.

Quote:

Originally Posted by Shaun 84 Targa

Sorry to hear it Mark, but why send them back? give them to Dan.

Because it will give me an excuse to come up and say hello

Shaun @ Tru6 · 10-30-2008, 05:28 PM

can't beat that! (on both accounts...come on up!)