Has anyone ever heard of something like this? This is a rear trailing arm from a race car. I've been running solid bushings and mounts on the rear suspension for two seasons. Problem or coincidence? The front control arms failures are well documented, but I've never heard of this before. Check your rears!

Steve (Sorry for the cross-post...)

 

wow that looks nasty

 

Never seen or heard of anything like that, and didnt think it was a potential problem other than from an accident/impact.

Does the car have any history of accidents?

87+ Trailing arm? N/A, Turbo?

Were you running full coilovers, combo, or torsion bars only? Spring rates?

How is the car built up? Stock weight or is it lightened?

How many track miles/events in the two season of solid bushings? How many miles on the car?

 

I recall 1 other lister who broke his at the track. His broke at the mount. He said he used the mount as a jack point, so perhaps he stressed it.

Can you tell us what the car did when it broke? It would be nice to know so we have an idea what to expect should ours let go.

 

Looks like a good candidate for filling the cavity with structural urethane foam to distribute stress better. Failing at that location seems odd though.

 

there is not enough load on that part to have it break like that.. something drastic had to be done....I would think It would break closer to the body mount end where is looks the weakest.

 

None that I'm aware of. I'm the second owner of the full race build.

Early offset (I don't know what defines the offset, though--arm or hub). Part number is 951 331 514. Are there different p/n's for NA, Turbo, M030?

Altogether in the rear: spherical trailing arm bushings, solid torsion tube carrier bushings, solid torsion tube block mounts, 525 lb coilovers, no torsion bars, Leda shocks, -2.5 degrees camber, 15x8" Fuchs, Tarret sway bar.

Full race build. The car runs at 2850 lbs with driver and 200 lbs of ballast.

About 20 days per year. About 60 miles of racing in a day... So 1200 racing miles in a year.

Steve

 

I looks like the impact did that damage, no sign of old-cracks on the casting.

 

Yea, the thing is... there's no history of impact in that corner of the car. The only impact that happened was after the arm broke... and on the opposite corner of the car. Makes me consider steel arms...

Steve

 

how do you tie the car down ..or lift the car up...something is pretty freaky about that part breaking where it did.

 

Tell me about it... Tiedowns are installed in the rear frame. I lift the car at the center jack point under the door sill and put stands under the torsion tube mount point in the rear.

 

Just trying to match the ID with the face...
Did I deliver rear suspension to you today??

 

That'd be me...

Steve

 

Awesome... Pleasure to meet ya and the spouse....
Sorry I had to bolt out of there but have lots on my plate...
That and my pants were covered in grease and I had another stop to make LOL...
Zipped home and changed :-)
Thanks for the purchase and good luck on the repair...
I will pick your brain about 944 cup cars later.
JC

 

hey wait- did you buy my car?