Front cross member wear

[aston@ultrasw.c]

My front torsion bars have wear marks as a result of rubbing on the torsion tubes.

Apparently the cross member wears such the the t bar moves off-center until it makes contact with the tube.

Can anyone post pics of the exact wear on the cross member so that I can be sure to buy a replacement in good condition (before I tear the whole mess apart )

Thanks.

[DaveMcKenz]

I am not sure I know where this wear is occurring. The rubber bushings do wear and leave the torsion bars off center in the tubes and can result in rubbing and wear. Maybe that is the problem.
Good luck,
Dave

[KTL]

Chris,

IMO the hole in the crossmember should actually be larger to ensure it doesn't rub on the t-bars. Especially when you have t-bars that are larger diameter and more likely to contact the crossmember when the A-arm bushings are compressed.

I noticed this same issue with my t-bars back in '08 and I put some thin strips of metal on the crossmember to build up the area under the t-bar cap and push it upward.

rubber a-arm bushing question

So you can see the area where the crossmember wears is just below the "apex" of the torsion bar cap. I used some steel flat stock that I ground down and heated up to bend it around the t-bar cap. Then I glued it to the crossmember with good 'ol JB Weld.

Here's some pictures of the t-bar cap within the crossmember before I put the piece of steel in there to support the cap

Turbo Tie Rot??

[DaveMcKenz]

I think Kevin has got the idea. My bushings weren't so worn that my cap contacted the cross-member. The bushing wear is the main problem, though. This make the t-bar off center, and this allows rubbing of misaligned parts such as the bar or the adjusting cap.
Dave

[Ferrino]

Wow, I had no idea this was a source of wear on the t-bars - will add it to the JB-Weld list!

[aston@ultrasw.c]

AH HAH!

That's it!

My car is high mileage 220 ish. So even though I have nice new bushings the tired old cross member is probably shagged.

I like having a game plan in my mind before I start pulling things apart, especially when it involves a home fab repair!

[Chuck.H]

I did the same thing as Kevin and put thin metal shims under the torsion bar end caps. My crossmember wore down at about 40k miles, and the bars started rubbing and squeaking.

I've had the same metal shims in place since then; they didn't wear out and the grooves didn't get any worse.

Chuck.H
'89 TurboLookTarga, 378k miles

[john walker's workshop]

I lay a weld along the bottom of the caps, then grind it down so the cap just fits into the crossmember for a quick fix. T bar rubbing is also the source of squeeking in the front suspension.

[KTL]

JW has the best solution in my opinion. I had yet to get a welder when I fixed mine up. Next time I have to deal with this i'm definitely doing the weld buildup on the cap solution. Thanks for chiming in John

[aston@ultrasw.c]

Both solutions have their merits:

Building up the cap with weld is a permanent fix, but as the cross member is aluminum won't it continue to wear at the same rate.

However, bonding a steel shim to the cross member raises the cap and provides a more resilient surface to resist future wear.

Isn't the shim a superior solution, as long as the bond holds?

[aston@ultrasw.c]

This thread is all about preventing the contact between the front torsion bar and the control arm tube.

Like this



I know, ugly right!

So I was inspired by KTL's solution here:

rubber a-arm bushing question

I disassembled the front suspension and found the exact same problem.

You can see the divot in the cross member more clearly here after I lightly ground the surface:



I reinstalled the t bar wrapped with tape so that it was centered in the tube.

Then slid on the cap and found I had a gap of about 1.3 mm to the lower surface.

So I needed a shim made from something hard, about 1.3 mm thick, and slightly curved.

After digging around for a few minutes I found some old 930 half shell bearings - how perfect is that?!?




As you can see I already cut a small arc segment to act as a shim.

Now I just needed to clean up the cap for a better bearing surface and the cross member for bonding:






MIG/TIG/JB weld




Don't let anybody say I don't use genuine Porsche parts on my car

[KTL]

Like I always say, your DIY fabrication skills are top notch. You come up with great ideas for materials! 930 rod bearing............. fantabulous!

[Driven97]

That. Is amazing.