1985 911 3.2L "torque steer" problem after ride height adjustment

[dereknickel]

1985 911 3.2L "torque steer" problem.

Looking for input on an extremely annoying issue I am having during driving. Some history of the car: I had the ride height lowered from US ride height to Euro ride height a few years back, torsion bar re indexed etc and front dropped. Ever since then the vehicle has driven strangely but very manageable, when I accelerate the car pulled a bit left, when I took my foot off the accelerator the car goes back straight/right. I took the vehicle to get new tires and an alignment after a bunch of work to the car and now the problem is 10 times worse, really pulls left under acceleration and swings back right when intake my foot off the accelerator. No strange tire wear noted by the shop on the old boots.

List of recent replaced items over the last few years:
-Strut assembly front left and right with new struts
-Struts replaced in rear
-Turbo tie rod ends installed
-Caliper rebuild front and rear, new rotors and pads
-Lower control arm bushings replaced
-Lower ball joints replaced
-Spring plate/torsion bar bushings replaced
-Front and rear sway bar bushings replaced
-Alignments and new Michelin Pilot Sport AS+

Thoughts fellow P car owners? I have asked my local shops to think on it, as well as my friend who is a Pcar master mechanic, so far not to many ideas have surfaced. I am assuming it is a chassis, suspension, weight, alignment issue etc. I really want to get this sorted so I can enjoy driving again.

[FrankM_]

Not an expert on this, but after all these changes my first thought would be to have it corner balanced first ?


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[darrin]

how low is your car now? Believe that the us/euro height discrepancy only applied to earlier (sc?) cars and by the time the the Carreras came around, all models left the factory at the same ride height.

Was the alignment performed by a shop/technician that's familiar with our 911s? What does the shop have to say about this issue. FWIW, my '86 targa (still at "normal" ride height, but set up by an air-cooled specialist shop) exhibits none of the behavior you're experiencing.

[Noah930]

Do you have a limited slip (or something else in the differential that's not working properly)? Sounds like the right rear is getting more power than the left rear, thereby "pushing" the car to the left upon acceleration. It's probably not as simple as tire pressure, because you've likely already addressed/checked that.

[dereknickel]

The car has not been corner balanced, I am trying to find an experienced shop for that job. On that note, the car was not aligned by a shop that specializes in our older aircooled 911s.... I just told them to align it when they put the new tires on.... I am having trouble tracking down a shop that really knows how to set up the suspension and driving dynamics on my 911. I might have off pre load on the fronts going on based on bad corner balancing?

I didn't realize the US and Euro cars were same ride height by the time the Carreras came out? I will research more.

My car does not have a limited slip differential.

The Porsche dealer a few hours from where I live has a Classic certification.... I wonder if they would have the correct jigs/tool for the rear spring plates etc. for the alignment and if they would have corner balancing equipment.

[rikaro]

check all bushings and then corner balance

[Flat Six]

Originally Posted by darrin

how low is your car now? Believe that the us/euro height discrepancy only applied to earlier (sc?) cars and by the time the the Carreras came around, all models left the factory at the same ride height.

Was the alignment performed by a shop/technician that's familiar with our 911s? What does the shop have to say about this issue. FWIW, my '86 targa (still at "normal" ride height, but set up by an air-cooled specialist shop) exhibits none of the behavior you're experiencing.

^^ +1
What are the final alignment specs this shop gave you?
Like Darrin, my 85 does not experience any of these issues.

Not likely an existing mechanical issue, since it seems the problem gets worse after you have work done on the car.

Without more info (and pics of your ride height would help too), here's my best guess:

Your alignment and corner balance are way off. Specifically, you likely have insufficient caster. The way you wrote the description, sounds like you lowered to Euro height (based on fender measurements or Bentley procedure?) and then lowered the front even more. Doing so limits the amount of caster you can dial in to the front which can create some squirrely steering behavior at speed, on crowned roads, etc.

With as much rake as it sounds like you've dialed in (again, pics would help), if the shop that did your alignment didn't max out the caster, that'll only worsen things. Having the "before and after" alignment readings will help. IME, shops that align primarily Detroit iron don't adjust in nearly enough caster unless they're working to a specific set of specs.

Lots of rake might look cool but IMO f's up front end geometry unless you've done it by raising your spindles.

This can also be compounded by the likely generous amount of bump steer you've potentially introduced by lowering the front so much (again, specs & pics would help).

[HarryD]

Where are you located?

When I first read this, I was thinking a Bump Steer issue. Look at you tie rods, are they parallel to the ground? If they are pointing up, you have a serious issue.

[dereknickel]

I will post the shops alignment numbers when I get home tonight. Yes Euro height based on fender measurements (which I know there is another way that is more accurate... centre of wheel to torsion bar?). I don't feel I have bump steer, but if I do it's not significant. Maybe at the end of the day the whole job just needs to be redone by an experienced air cooled porsche mechanic/shop. Ideally I just want to drop the car off, let them keep it until it's all sorted ( I don't care how long it takes...) and then come and pick up. I might have to dive to Cali for something like this haha. I currently reside on Vancouver Island, BC, Canada.

[gtc]

Call Jeff Alton at Turn3 Autosport in Vancouver (Langley). Not sure if they do alignments in house, but if not he should be able to at least point you to a competent shop.
He is also a member here, FWIW.
There are no special tools required to align or corner balance these cars, you just need to know what you're doing.

[dereknickel]

Thanks for everyone's input today. I had a good chat with my closest Porsche center and they have someone who specializes in suspension set up, corner balancing, ride height and alignment. They set up custom track cars etc all the time apparently and just did a 964 last week for ride height, corner balancing and alignment. Said they know the old cars and are Classic certified blah blah. Figure I'll give them a shot, only place I have called that had a somewhat confident response. I've never taken my car to a Porsche center, first time for everything I guess. Booked in for July for the specific guy that's going to work on my car.... Have to wait now.

[Geneman]

You reaslly need someone who knows these cars inside and out to get setup correct. They are extremely sensitive to weight dist, ride height etc.,.. I can feel it while burning off gas during a 1.5 hr enduro event on track....

[Flat Six]

Originally Posted by dereknickel

Thanks for everyone's input today. I had a good chat with my closest Porsche center and they have someone who specializes in suspension set up, corner balancing, ride height and alignment. They set up custom track cars etc all the time apparently and just did a 964 last week for ride height, corner balancing and alignment. Said they know the old cars and are Classic certified blah blah. Figure I'll give them a shot, only place I have called that had a somewhat confident response. I've never taken my car to a Porsche center, first time for everything I guess. Booked in for July for the specific guy that's going to work on my car.... Have to wait now.

Good deal; just make sure you've finished whatever suspension refresh/upgrades you're going to do before you take it it. BTW, looks like you have a lot of camber up front -- I like to run -0.5 degrees. It looks like your front end is a little too low . . . .

[sparkysvega]

Could the brakes be hanging up in the front , after your caliper rebuild ? I had a car that was doing this and the front calipers were not releasing .

[smadsen]

Check something simple.

Front tire mounted on rear wheel or ?. Measure the circumference of tires side to side after you equalize the pressure. Measure with a tailors tape.

[911pcars]

The chassis can be aligned to spec, but still pull to one side, especially when braking. This is due to uneven corner balance due to incorrect ride height settings or previous collision damage.

The result is that one or more corners aren't supporting their correction proportional amount of chassis weight - car needs directional correction when braking. Confirm by moderately heavy braking, hands off wheel (in a safe area).

Here's one way to isolate which end is "off". This is described in the repair manual, the so-called Tripod lift.

Disconnect one end of each sway bar, front and rear. Isolate front and rear ride heights by lifting one end off the ground, then measure the ride height of those corners on the ground. This method isolates one end from affecting the ride height of the other end and allows you to ID what corner is "off" (supported weight isn't the same).

To perform this Tripod lift, must lift one end at a mid-point between left and right side. For example:

- At the front, span a 2x4 or 4x4 on edge under each front torsion bar front mount, then lift in the middle and measure the rear ride heights (ground to top of wheel well opening is quick and dirty).

- At the rear, lift in the middle of the transmission crossmember, then measure front ride heights.

Using corner balance weight scales is more accurate. However, due to chassis characteristics (or collision damage), the ride height at each corner may end up slightly different even though the chassis is correctly balanced. The left side, front to rear ratio should be about the same as the right side, front to rear ratio. Your call as to your preference.


Sherwood

[GH85Carrera]

It is hard to find an alignment shop that knows any cars from the 1980s. I had to ask a lot of friends with old cars to find a shop that could align my 1986 El Camino properly.

I was lucky with my 85 911, the local dealer had one "old grey" factory trained mechanic that knew old air cooled 911s. We did a 4 wheel alignment and corner balance and it really helped. It does not have even a hint of "torque steer" and handles great.

[Nick Triesch]

I would just have a shop put the suspension back to factory settings and ride hight. I bet it was fine before.

[alexandervdr]

Originally Posted by dereknickel

......On that note, the car was not aligned by a shop that specializes in our older aircooled 911s....

My 86 had similar issue when I bought it. I aligned wheels myself using simple tools, problem solved and I'm NOT a specialist. I experienced that for anyone who has to go through this, it's a learning experience cause the way camber/caster/toe adjustments interact one with the other on a 911. So even for a shop with plenty of experience but none on old 911s they might have missed something.

From a pure 'logic' point of view, it could well be the rear wheels are not aligned (toe difference left/right) with the centreline of the car.

But caster and camber differences can lead to pulling the car too. I found these short videos interesting

https://www.youtube.com/watch?v=7q2grQILEVo

https://www.youtube.com/watch?v=PY5rnOg_2qs

[jjeffries]

Rear end torque steer might also suggest wear in the rear @ the trailing arm bushings. Known to those of us who’ve had Alfa’s, 70’-80’s BMW’s, etc. I realize these get less wear on a 911 due to the spring plate sharing the load, but no harm in checking both, using a good pry bar (wheels off or at least off the ground/not bearing weight).

If the car’s components are all good, and if you’re feeling a little adventurous, setting up a string alignment might be revealing, to see what front and rear toe looks like. Takes some time and patience, as noted by the gentleman who responded just before me. I too did my own alignment (after some refresh work, not to cure a specific problem) and I have a straight-tracking and predictable/benign handling SC afterwards.

PS Re-reading this now, I should add that I also borrowed a set of scales and corner-balanced mine as part of my home alignment.
Best of luck to you,
John