Carrera front torsion bar failure (think I averted disaster)

[r-mm]

Took my 87 into New York this weekend to see some friends, and planned on driving myself to the airport on Monday morning. Sunday night I was showing it off to some friends and noticed a fine shredding along the outer corner of the P/S F tire, almost like someone took a vegetable peeler and made very fine slivers of rubber with it. On closer inspection, that wheel was about 1/2" to 1" closer to the wheel arch than the drivers side, which had no tire rash. I thought it through and decided it was not worth chancing it and had it towed home. I'm now away for work but trying to diagnose the problem.

Everything I know, and some advice I've got from 911 buds points to torsion bar probs. Whether its the male or female splines or the meat of the bar itself that may have failed, I do not know, but I can't see what else would have the ride height messed up like that when the car is at rest, parked, level.

If it is the t-bars, what else would be on your while you're in there replacement list? So far as I know, the suspension hasn't been touched on this car, which has 107k miles and was well kept by the PO, but he was not an obsessive preventative replacement type.

I would never have noticed this if I wasn't showing the car off to some friends at a BBQ. Good reminder to keep an eye on your car, walk around it every now and then and give it a good looking at. For safety's sake.

[gtc]

It would be a good time to look at your a-arm bushings, ball joints, and tie rods, and replace as needed.

[GH85Carrera]

I replaced my T-bars a few years ago. Both had wear and would have broken by now. Any Carrera from the 80s should have the t-bar bushings replaced by now. If they have not been replaced it needs to be on the to do list.

[r-mm]

Of the products on the market today what is considered the best OEM replacement? I want to keep my ride height / rates stock.

[gtc]

Elephant Racing rubber bushings, Lemforder ball joints and tie rods. You can probably find some stock torsion bars in good shape here on the classifieds for $100 or less for the pair.

[CountD]

Originally Posted by GH85Carrera

I replaced my T-bars a few years ago. Both had wear and would have broken by now. Any Carrera from the 80s should have the t-bar bushings replaced by now. If they have not been replaced it needs to be on the to do list.

These are words of wisdom, because I believe that this area is very, very often overlooked and the original bushings on almost all air cooled 911s are smoked by now.

[redridge]

sounds like a drastic failure to have it that much difference in ride height... proceed with caution.

[Jcslocum]

Originally Posted by redridge

sounds like a drastic failure to have it that much difference in ride height... proceed with caution.

Caution is Rus's middle name when it come to projects. He will get it RIGHT.

I used Elephant rubber bushings on mine when I did it.

[OsoMoore]

Was the gap difference up-and-down, or sideways? It is my understanding that many of these older cars are slightly off-center as they were hand-assembled.

Mine is about 1/4 inch towards the driver's side in the rear. This led to a slight tire shaving with wider wheels on fast turns. I changed wheels, although in retrospect I could have rolled the fender or adjusted the suspension slightly.

There was a thread about it somewhere around here, but I can't find it at the moment.

[Smoove1010]

Lesson learned: Be a show-off for safety's sake! Sounds like it's time for a front suspension refresh, and there are many really good threads on this topic. This one is my favorite, though I'm not going nearly as deep or as performance oriented as CraigD did: '78 SC Elephant Racing Suspension Rebuild

I'm about to embark on a more basic, stock street version of a refresh: 87 Cab Suspension Refresh: How’s My Plan?

I figured it's a good time to inspect, refresh, service, or replace:
- Shocks;
- Shock mount bushings;
- tie rod ends;
- sway bar bushings;
- ball joints;
- steering rack;
- all rubber fuel lines at the back of the fuel tank.

I already did the following when I first took ownership:
- rebuild calipers;
- check, clean, re-pack and replace front bearings;
- check/replace pads and rotors;
- replace front brake hoses.

Once my parts arrive, I figure it will be two weekends and week or so of evenings after work to get this done, depending on how fussy I get about cleaning up and painting parts.

I'll be curious to see what caused your tire-shredding issues. Good luck!
GK

[KTL]

Rus,

Put up some pictures when you get a chance. I'd like to see how that tire contact occurred. As I said in my email, it's surprising to encounter tire contact with stock 6 in. wheels and 205 width tires. For instance when you drive it on the track, the stock suspension compresses very much and that would sort of simulate a torsion bar failure with that much suspension travel. Never seen the stock wheels & tires have contact under those conditions.

Nonetheless good for you to catch that issue and avoid the potential for a roadside wrenching affair.

Agreed the front A-arm bushings are an issue with these cars. Over time they "cold flow" and you end up with offset bushings in the bushing carriers. That offset condition allows the torsion bar to rub on the crossmember, which rubs off the paint and invites rust to break the t-bar.

Another thing worth noting is when you upsize the t-bars. The bushing issue becomes of greater concern because the larger diameter t-bar makes it easier for rubbage to occur. Even with new rubber bushings you can have rubbage. But that's with larger t-bars and putting them to the test on the track. That's just the nature of the rubber compressing due to heavy loading.

[GH85Carrera]

I went with the Elephant racing rubber bushings.

Suspension is a VERY slippery slope. It is easy to get carried away with "while I am in there" and make your saving account vanish.

Start with a plan on what you want when you are done. I wanted basic stock but a little tweaking was OK. Do a LOT of reading on the subject. There are enough suspension threads on this site to keep you busy for a while. Plan ahead, think it out and stick to your plan.

I am very happy with the transformation of my car and the suspension.

[r-mm]

Thanks guys. I'll be back with the car later this week and will certainly document the conditions as I find them. I could be wrong about the T-bar failure. Kevin as I mentioned in my email - I was driving the car, with gusto, around Brooklyn, so could it be that the combination of some ride height problem and rather extreme potholes at speed could have caused the contact? The shaving was quite fine - like I said, thin little strips like fancy carrot shavings in a salad were peeling all around the very outside corner of the tire. I understand that stock suspension will flex a great deal, but wouldn't NO suspension flex a 100x greater deal, on top of riding low at rest?

OsoMoore - the problem was up/down not left/right. From memory I'd have to call it a full inch at rest, but will measure.

[Chuck.H]

I would think if the T-bar failed the wheel would be stuffed up in the wheelwell and resting on the shock bump stop. I have hit some of those NYC potholes and moved my top strut enough to greatly change my castor / camber, which does move the tire, but mostly in/out.

That movement is sometimes easy to spot because it moves the putty around the strut so you can see a gap from where the plate used to be.

I always liked the NYC potholes that were so large some kind person put a garbage can in them to warn others.

Chuck.H
'89 TurboLookTarga, 375k miles

[r-mm]

Chuck - its entirely possible that what you say happened. I didn't hit any whoppers, but was doing 30-40 over some continuously spalled, nasty bridges and highways so who knows. I'll measure and then start taking things apart to figure out what happened.

[r-mm]

Okay this is a bit of a mystery. I measured the distance from the (fairly level) garage slab to fender @ wheel center line and got 660mm one side and 663mm on the other. I pulled the torsion bar on the offending side and found it to be in perfect shape. I'm now wondering if the rubbing I saw on my tire (picture tomorrow in the daylight) was from a curb... although I really don't think so.

Has anyone seen any shredding/rash on the outermost edge of the tire just from city driving / stock suspension compression? My suspension, wheel and tire package is 100% stock. 205's up front, and brand new too.

[r-mm]

Its probably not a bad idea for me to go through the suspension and give it a general freshening up a la Smoove1010's plan, but first I think I should drive it, carefully, to see if I get any more rubbing. Nothing worse than an undiagnosed problem. So - pardon the dumb question - but what does one need to do in terms of "indexing" the torsion bar when re-assembling it? I have a jack stand under the A-Arm and haven't moved anything since I removed it, but I didn't mark it when I took it out.

[r-mm]

Turns out the offending tire, damage pictured, was a 7J 16 instead of a 6J 16. Somehow either I or the tire shop was responsible for a mixup whereby I have a 6 and 7 on the front and back. The tire sizes are correct, but the wheel width is not.

Easy enough to correct. I'll run it by the group just to be sure...

After swapping them right way round I will end up with
7Jx16 23.3 ET on the rear, wearing 215's
6Jx16 36 ET on the front wearing 205's.

I don't think it matters, but I'll ask anyway - the fronts have different part numbers, but based on this chart they track back to the same wheels size, just the 'early' and 'late' versions.
911.361.020.43
911.362.113

Another dumb question. Why doesn't this happen when people upgrade to 7's and 8's or 7's and 9's, I'm presuming a different 7" is used for the front to compensate for the offset problem? If not, then there is maybe another problem lurking that I haven't diagnosed yet.

[LJ851]

All the 16" 7's have the same offset. People roll their fender lips if there is a clearance issue.



The 6 and and 7 inch wheels look noticeably different, How long have they been mis matched?





.

[r-mm]

So it seems feasible that I could be getting rubbing from stock fenders with 205s on 7" Fuchs (in NYC, with tired old shocks)?