jeffnudd

I was on my way today for a game of golf about five miles from the house and following a M3 which was trying to get my attention, problem is he did, i wont mention the speed but as i was creeping up towards his rear end we were going pretty fast, and the car felt extremely unstable.

This is what i have do so far to try and eliminate the problem.
1. 4 wheel alignment
2. checked steering rack for stiffness, which it is compared to a normal steering rack, so i cracked off the trackrod ends and the stiffness disappeared?
a bit strange as the trackrod ends have no play? anyway....
3. checked for anything bent on the steering and suspension components.
4. 4 wheel balance including 2 new rear tyres.

Is there something i have overlooked or are 964's very rubbish at very high speeds?

I did notice when i checked the front shocks the other day they looked ok, i did a bounce check and nothing really happened, they dont seem to be leaking fluid unless they are gas struts? The shockers fitted are the factory ones.

The steering i have to admitt does feel stiff as if i am turning sharply at very slow speed and leave the steering wheel it does not self centre. i did crack off the track rod ends mentioned above and the stiffness did go at the wheel and the bearing at the top of the stuts felt very light, are these track rod ends prone to going bad or very very stiff , so stiff that the steering is very strange.

Thankyou for reading.

Cheers

Jeff

P.S. Just to add, the M3 would not get out of the way, i think he thought he was winning.

Sten

Maybe his slipstream upset you? The 964 is pretty stable even at high (Autobahn) speed.

DaveK

It's definitely not normal for a 964 - they are very stable at speed.

The fastest I've ever been is an indicated 170mph many years ago (autobahn obviously). My g/f at the time wasn't wildly impressed - but even she commented that it was totally stable and really didn't feel any different to 50mph.

jeffnudd

It is a very strange problem i have, i just cant put my finger on it? i think i might try the trackrod ends first of all and see if that improves the handling.
The 4 wheel alighment i have checked twice.

I noticed the problem a few weeks ago and thought it was just pilot error but today fightened the living daylights out of me, i though for a moment it was just going to flip over.
Yes thats how scared i was. the steering is very stiff.

Bluey964

My thoughts would go towards dampers, especially if they are the original ones on the car. When I first got mine five years ago it was unstable at 90mph or over, then changing to Bilstein shocks on the original springs gave it a much more solid and stable ride at speed.

jeffnudd

I think you have a point the shocks have had 90,000 miles of punishment maybe its time to give them a change aswell.

I still cant understand why the trackrod ends joints be so stiff, i have never come across this before in all the years ive been working on cars.
I have had the top strut mounts seize before on cars but never trackrod ends?

CraigyB

maybe a loose nut behind the wheel ?

rodders

cruising at a GPS measured 140+ in Europe - no problem
90k on your shocks - well they need changing
- the only time i have felt stiffness of any kind was when the rack was leaking or i remember i had put the wrong fluid in a top up - mixing fluid can do strange things.
Worth checking - change the fluid and make sure its correct - yes i remember very well mixed and wrong power fluids made the steering stiff and very odd

rodders

Jeff - just read your post again and dug into the memory - I had identical symptoms - mixed fluid gave stiffness on hard lock at slow speeds - also no self centering - completely cured with a change of fluid in the power steering system
Good luck - let us know

unclebilly

My car has been up to 125 MPH recently and it was very smooth. No floating.

Have you adjusted the ride height? What is the air pressure in your tires? Is your air dam damaged?

Christer

When you say 4 wheel alignment - does that also mean adjusting the camber and toe etc? Also, check tyre pressures.......and even wheel balancing....

robmug

Another thought - tyres.

Are all 4 the same brand/tyre? How old/worn?

I had to drive with a mixed set about a year ago for a month or two and my (normally extremely stable...I've been to redline in 5th) 964 felt awful above 60mph.

Edgy01

Was your spoiler working? (Does it deploy at 50 mph as it should?) There are many issues that can lead to your symptoms,--I always start at tires. You replaced two,--what shape are the others in?

I go by the process of elimination which tends to discount the rarer things out of hand. Tires are the leading cause of stability problems.

jeffnudd

UPDATE SO FAR:

I changed the power steering fluid today (twice just in case) and while i has the fluid out i replaced the tiptronic gear oil aswell, i then decided to put the car on my fourpost ramp and had the front wheels on turn plates, it turns out that the steering is as free as a bird so it looks like i was barking up the wrong tree.
But i do recall a slight differnce
The tyre pressures are currently: Fronts 36 psi and the rears are 44 psi.
As for the four wheel alignment that is only tracking and steering wheel position as it had taken me forever to track it correctly and get the steering wheel dead on straigh as it drives in a straight line, there is nothing more annoying than a offset steering wheel.
Is there a tool i can buy for setting up the camber, as i would like to check this out just incase i have a problem there?
I was thinking today that the spacers on all wheels maybe a problem? because the car is fitted with cup 2s spacers are required for the fronts because they rub the arches but because the fronts were out slightly i decided to buy a pair for the rears, the spacers however are only 7mm thick so i would imagine that wouldnt create a problem.
I know when your reading this you might be thinking ahh tyre pressures but i did try 36psi on the rears some time ago when i read a thread suggesting this but i did think the rear felt like is wondered a bit so a promply adjusted them back to 44psi again, any thoughs on this would be appreciated.
The spoiler definately works at the 60 mph mark and retacts at walking speed which i assume is correct.
The tyres are in good shape, the rears are new and balanced then up again just for good measure, the fronts look worn on the inner edges slightly but that was due to the tracking being out slightly (2-3mm) whick is now cured (hopefully?). The make is Mich pilot sports zr17s all round.
I did check the front shocks again today also but couldnt find any leaks, (dry as a bone) i have seen other cars that have done far far more than mine on just the one set, should i change them?

I wont take it upto the kind of speeds i had it to on Sunday untill im sure its not going to frighten the ****e out of me again so im pretty anxsious to get this one sorted before it kills me.

Brilliant feed back so far guys thankyou.

I wont take up any more of your time, my appologies for rambling on.

Cheers

Jeff

Pesty

my 964 is rock solid at 150. In fact the faster it goes teh better it gets