I need help with wheel alignment.

[83SC]

I need help with wheel alignment.

I have a 1983 SC that started tracking badly. It felt like the rear tires would follow groves in the road and there was no weight on the front suspension.

I found the left rear shock blown and replaced both rear shocks with Bilstein Sports. Now the problem is worse then before, same symptom and more of a jerking motion from side to side.

I took the car to a shop and had the wheel alignment done. The rear tires still track and now when I accelerate the car pulls to the left. I took the car back to the shop and they claim the alignment is correct and something else is causing the car to mishandle. They questioned the shock replacement because the rears felt loose and not stiff like the fronts.

The shop claims to have done many wheel alignments on Porsche 911s and they were recommend by a Porsche repair shop. This seems like a typical wheel alignment problem and at this point I am not confident in the shops knowledge of the car.

What are the correct alignment settings for a 1983 911SC / for normal street driving?

Does anyone have recommendations on an alignment shop in the Sacramento CA, area?

Thanks.

[stlrj]

To begin with, what numbers did the shop align your car to?

Can you post some pictures of how your car looks as it sets?

[Gunter]

The shop would have given you a written print-out that shows the "Before" and "After" settings.
Scan it and post the numbers.
Also, did you have them do a cornerbalance?
Some facts:
Shops have the factory numbers in their system and will use these unless you give them Custom-specs that most 911-owners use.
Before and during any alignment, all bushings and ball joints are checked and possibly replaced along with the shocks.
Most people set the height first, then do the alignment and cornerbalance together.
It is possible that your cornerbalance is out of wack.
New tires are preferred for an alignment.
A good shop would find the problem.

[cgarr]

Just because its in spec does not mean it will drive correctly down the road, We always ask the customer, "do you want it set to spec or do you want it to drive right?"

[stlrj]

Originally Posted by cgarr

Just because its in spec does not mean it will drive correctly down the road, We always ask the customer, "do you want it set to spec or do you want it to drive right?"

Can you elaborate? What issues do you address to make it "drive right"?

Can you share with us which specs you tweek?

[cgarr]

Originally Posted by stlrj

Can you elaborate? What issues do you address to make it "drive right"?

Can you share with us which specs you tweek?

Caster.

[83SC]

How do I attach an image?

[Gunter]

Originally Posted by 83SC

How do I attach an image?

Click on "Post Reply"
You'll see: "Click here to upload photo"; click on it and follow instructions.
Has to be the recommended format like jpeg etc.

[83SC]

[Thrasher]

Not commenting on your specific numbers here but:

Even with a "properly aligned" car:

1. poor corner balance can cause the car to pull (towards the heavy corner, IIRC).

2. a dragging brake caliper can cause the car to pull

3. a tire issue (e.g. tread separation, certain out-of-balance issues) can cause the car to pull

4. Mismatched (especially R-L) or worn tires can cause the car to pull.

A 911's rear alignment adjustments are quite different to what JimBob sees everyday. You are very well-served to find a good independent shop that specializes in air-cooled era 911's, or if they don't align, go to who they send their alignment work to.

Don't assume that the printout is necessarily an accurate reflection of your current alignment. I can't tell you how many times we found shops who abused their equipment, didn't calibrate the aligners and experienced "comebacks" from customers dissatisified with their alignments.

That printout is not from a Hunter aligner, which most consider to be the industry standard.

PS: you have over a 1/2 degree diff on R-L Front Camber... that is not what you want.

[stlrj]

Originally Posted by cgarr

Caster.

Are you talking differential caster settings? How about camber?

[JWLindsey]

FWIW, those settings look all messed up to me too. They have dialed in more camber on the right side of the car and then also set the rear toe differently on each side. Radial Tire did a fine job for me mounting and dismounting some tires, but it looks like they gomered this up pretty nicely. I guess some argument could be made that they did this to account for road crown but that looks way off to me for a car as sensitive to alignment as the 911 seems to be. The pull to the left on acceleration is probably the car reacting to the greater bite on the right side with the same gig happening under braking when the increased camber on the right causes it to dart left. Not so good.

As for local alignment houses, I recently had Ron at IPB Autosport corner balance and align my '87 which made a world of difference in how the car worked. It tracks true on both braking and acceleration with no tramlining or other problems, so you might have him take a look to see how off the car is on the weights and alignment settings. He did farm out the alignment to someone else, but the settings were set to be even on either side (1/8 toe in both ends, -1.4 camber front, -1.9 camber rear).

Good luck.

-JWL

[Gunter]

+ what others have said.
Because the front cambers have a 1/2 deg difference between L/R, I would go back and ask for some refund.
Find a better shop.
Before you go you can do a few things yourself:
Lift the car and check for any play in the wheel bearings and also make sure there is no wobble in the rims.
If the main bushings in the rear spring plates need replacing, do that first.
Decide on overall ride-height and do the alignment and cornerbalance together.

[Thrasher]

I'm with Gunter. An alignment is necessary, but until you get the base issues sorted, you're sort of kidding yourself that the car will perform as new.

I replaced my rear spring plate bushings, then the rear shocks. I also have new shocks, tie rods, control arms, ball joints in front. I lowered to Euro height and added the rack spacers.

I did a home corner weighting by measuring my chassis point heights, placing bags of water softener salt in the driver's seat as ballast. When my car went on the scales, it was within spec, and only 'off' by about 19 lbs on the one diagonal - which is imperceptible on the street.

My 84 with 165k miles tracks and corners like it's on rails. Definitely worth the time and effort.

Home ride height and corner balance success story