Unable to get proper rear toe-in alignment

[Mike Bonkalski]

My alignment guy and I are stumped on our inability to dial in any rear toe-in on the right rear. When the eccentric is at the end of its range, we are still at a toe out situation. The eccentrics have been 180'ed to see if it would help - no luck. All of the other wheels are spot on.

Any suggestions on why we can't get the toe set correctly?

Btw, the reason for the alignment is installation of new polybronze bushings and monoballs.

--Mike

[nhromyak]

You need to set camber first.

IIRC you need about negative 1.0 degree (sometimes more) to get toe, especially if it's lowered.

Good luck.

[Mike Bonkalski]

We had the camber at negative 1.8 degrees with no luck.

[nhromyak]

Is it close?

My alignemnet guy(s) said to try and hollow it out, but I was afraid of that.

I am out of ideas then, unless it the ride-height is REALLY low, or too high?

[Mike Bonkalski]

Now what I understand is that they are running out of room where the spring plate meets the swing arm. He said it seems like the swing arm is too long.

[MotoSook]

Mike, did you notice this before the rear mono ball install? You've got aluminum trailing arms right?

[Mike Bonkalski]

I will have to go through the PO documentation to see if I can find any old alignment info. I didn't take any toe measurements prior to dismantling to install the monoballs and bushings. I didn't notice any odd handling characteristics while driving the car, but it was mostly highway and around town driving.

Yes, the trailing arms are Al.

--Mike

[Mike Bonkalski]

I don't think the ride height is too low, or too high. I measured it at 25.25" prior to the alignment.

--Mike

[MotoSook]

You've got an SC suspension on a 71 chassis right?

Perhaps someone out there who has done the conversion can tell you what is up. I can't think of anyhting off the top of my head right now....wish it were a Friday afternoon, I'd run over too Jms and get greasy just to find out why...I'm intrigued!

[Mike Bonkalski]

Its a Carrera rear suspension on a '71. Jim and Joe are both working on it now. I'm about the head out of work now and go on over.

--Mike

[MotoSook]

I wonder if your problem exisited before and you just didn't notice.

[ChrisBennet]

On an 80's 911 when you crank in a lot of negative rear camber (more than 1.5deg for example) it causes the suspension to toe out. At some point the there isn't enough adjustment in the spring plate to get toe back (in) where you want it. The fix is to lengthen some holes in the spring plate. I can't remember which ones.
-Chris

[RoninLB]

spring plate

[Chuck Moreland]

The problem exists on the passenger side only? Could be a bent trailing arm.

Is the toe eccentric freely rotating 360 degrees? or is it limited in travel due to the rear bolt holes Ron is referencing above? You can test this by removing one of the bolts, or replacing it temporarily with a smaller diameter bolt. If so, use a file to elongate the slotted holes.

Are you make the adjustment with the weight off the wheels? You'll find more range if you unweight it.

[Chuck Moreland]

If none of that works, some clever work with a welder and a file and you can move the toe hole forward a bit on the spring plate.

Or some clever work with a welder and lathe and you can accentuate the eccentric adjuster a small bit.

There is always a solution.

[jluetjen]

My car has the same problem and I put to down the the previous owner parking it againsts a guard rail at Watkins Glen. I attributed it to bent chassis, although I haven't been able to confirm it with measurements. I opened up the hole that you described, but I also had to do the same thing to the slotted adjuster hole to give it enough travel.

Since the problem existed with the original steel bananas and the aluminum bananas that I have since installed, I still believe that it is the chassis or torque tube.

[Thomas Owen]

You may find here that the problem already existed. Perhaps you can make some basic measurements across the underside of the car and see if the torsion tube is swept back on the right side from impact.
Good luck-

[Mike Bonkalski]

What would have the highest margin of safety, using a smaller bolt or enlarging the hole?

It concerns me a bit to start shaving off metal from connection points or using non-spec bolts.

--Mike

[Tim Polzin]

Originally posted by Thomas Owen
You may find here that the problem already existed. Perhaps you can make some basic measurements across the underside of the car and see if the torsion tube is swept back on the right side from impact.
Good luck-

An old 70T I previously owned had exactly that problem. Half an hour on the frame rack cured it and dialed right in afterwards.

Tim

[Mike Bonkalski]

Just talked to the alignment guy. It looks as if the aluminum trailing arm is bent, the rest of the frame is spot on.

Off to the classifieds to find a trailing arm. Thanks for everyone's help with this issue.

--Mike