Need an Alignment or something more serious?

[Ez-Bone]

Lately I've noticed my car tracks kind of... weird.

It will occasionally wobble or even sling to the left or right at speeds over 30-40mph and when I make a turn, there's sometimes a 'ching-ching-ching-ching' sound as if someone sharpening knives against a slab of wet metal. Its hard to pin point the sound from inside the car but it sounds (guessing) like it's generating from the rear driver wheel...

I remember the first time I felt and heard similar symptoms, the bearings IN THAT SAME WHEEL went out and I had to replace that entire trailing arm cause the bearings were scorched and welded themselves into their seats.

Do I just need an alignment or is it more serious? like needing new bearings and anything else?

Please lend me your knowledge, wanting advice immediately and thanks again everyone, you've all truly been a great help to me

[curveto]

Is the back or the front walking around?

If it's the former something is probably broken. If it's the later, is it just bump steer you're feeling (perhaps due to road rutting)? Is it happening *very* fast? If so, does the steering wheel pull (or not) when doing so?

How much static play do you have in the front (or I suppose rear) wheels when at rest? When parked, grab the top of the tire and push it in/out. The rears shouldn't really move at all. The fronts may have a little play (but not much).

Is the inside of either front tire wearing abnormally?

Do you have a loose tie rod? When parked, grab the tire (from the rear and front, two hands) and push/pull (a "turning" motion, if you will). Any clunking or slop when doing so?

> cause the bearings were scorched and welded themselves into their seats

That seems rather odd/extreme. The inner race should have been removable regardless of what the bearing did (or didn't) do to itself. Hmm...

[Ez-Bone]

Originally Posted by curveto

Is the back or the front walking around?

If it's the former something is probably broken. If it's the later, is it just bump steer you're feeling (perhaps due to road rutting)? Is it happening *very* fast? If so, does the steering wheel pull (or not) when doing so?

How much static play do you have in the front (or I suppose rear) wheels when at rest? When parked, grab the top of the tire and push it in/out. The rears shouldn't really move at all. The fronts may have a little play (but not much).

Is the inside of either front tire wearing abnormally?

Do you have a loose tie rod? When parked, grab the tire (from the rear and front, two hands) and push/pull (a "turning" motion, if you will). Any clunking or slop when doing so?

> cause the bearings were scorched and welded themselves into their seats

That seems rather odd/extreme. The inner race should have been removable regardless of what the bearing did (or didn't) do to itself. Hmm...

Well, I can't exactly pin point too well where it's coming from but I have noticed the wheel will 'jump' sharply but I've grown so used to it I can just about anticipate it absentmindedly. Just as a test to make sure I wasn't loosing my mind, I floored it down a straight away and got confirmation something wasn't right. The car ripped to the left and proved 'slight' difficulty getting it back straight.

The front tires are fine, even wear all around and I know you can just about feel every little defect in the road with these cars but almost every bump I hit the car tries to run off in that direction. If I'm cruising a newly paved street then it's not as bad but the pulling is still there.
Sometimes it feels like the arse end is going to slide out to the side if the front isn't pulling.
I'll try and explain it better as I check it over some more

As for the tests, I will do those too and get back with you as soon as possible

As for the bearing incident, I have pictures of the situation cause even myself was still in disbelief when I saw the damages.
it happened like this:
When I got the car home, of course the wheel was all crazy, cocked in. took it all lose then the hub and the axle is just bouncing around mind you.
I undid the CV bolts and started to pull the axle out then scorched and burnt balls and rollers (well... what was left of them) spilled out. I wanted to cry once I saw the damages, luckily I was able to pound the outer bearing race out and clean up the seat nice and good for a new bearing, but the inner seat was a whole new story. The inner bearing's outer race literally welded itself into the seat! Hell, it looked like it was apart of the trailing arm! I then checked the axle for any hope, only to be depressed again as the spacers aswell as BOTH inner and outer bearing races were stuck on.

With just that brief story, you can kinda see why I'm paranoid with and scared of this car's bearing setup

[Zero10]

Sounds like a worn out intermediate shaft on the steering and a dust guard is dragging on the rotor for the noise. Usually bearings will rumble, and if its coming from the back that really narrows down what can be causing it.

My intermediate shaft is toast and as a result my 951 drives the same way. It'll be perfectly fine then you hit a little bump or rut in the road and it pitches hard one way or the other. Rather randomly, and the wheel reacts a split second later with a thunk before pulling hard.

[Ez-Bone]

Originally Posted by Zero10

Sounds like a worn out intermediate shaft on the steering and a dust guard is dragging on the rotor for the noise. Usually bearings will rumble, and if its coming from the back that really narrows down what can be causing it.

My intermediate shaft is toast and as a result my 951 drives the same way. It'll be perfectly fine then you hit a little bump or rut in the road and it pitches hard one way or the other. Rather randomly, and the wheel reacts a split second later with a thunk before pulling hard.

Intermediate shaft?
Don't quite have a minds picture of it (still learning about other things other than just the engine and it's operation characteristics) but I'm guessing it helps the car track straight.

How much would a new one set me back?

[curveto]

Originally Posted by Ez-Bone

Intermediate shaft?
Don't quite have a minds picture of it (still learning about other things other than just the engine and it's operation characteristics) but I'm guessing it helps the car track straight.

How much would a new one set me back?

You should be able to detect that condition with this test:

When parked, grab the tire (from the rear and front, two hands) and push/pull (a "turning" motion, if you will). Any clunking or slop when doing so?

You might want to put the car on a lift and/or start it (idle, neutral). ...if you don't feel anything obvious during the static (parked) test.

[Zero10]

Shaking the tire will tell you nothing about the intermediate shaft. The gearing in the steering rack itself will be the limiting factor here.
It will however tell you if you have bad tie rod ends or ball joints and you should test them because they need to be tight for the intermediate shaft test to be accurate.

To test the intermediate shaft, turn the car off and park on relatively sticky ground (clean pavement for example). With one pinky finger on each side of the steering wheel (or another finger using light pressure), rock the wheel back and forth. The tires should be staying put properly due to friction with the ground, and without power assist you are feeling any play there is between your steering wheel and the rack. You will need tight tie rod ends and the steering rack mounts will need to be tight for this test to be accurate. You should feel very little play at all. More than 1/64 turn or so means something is loose. You should be able to have a friend repeat this test and trace where the looseness is coming from. Typically the U-joints in the intermediate shaft wear out and the looseness they produce can be really hard to track down.

[Ez-Bone]

Originally Posted by Zero10

Shaking the tire will tell you nothing about the intermediate shaft. The gearing in the steering rack itself will be the limiting factor here.
It will however tell you if you have bad tie rod ends or ball joints and you should test them because they need to be tight for the intermediate shaft test to be accurate.

To test the intermediate shaft, turn the car off and park on relatively sticky ground (clean pavement for example). With one pinky finger on each side of the steering wheel (or another finger using light pressure), rock the wheel back and forth. The tires should be staying put properly due to friction with the ground, and without power assist you are feeling any play there is between your steering wheel and the rack. You will need tight tie rod ends and the steering rack mounts will need to be tight for this test to be accurate. You should feel very little play at all. More than 1/64 turn or so means something is loose. You should be able to have a friend repeat this test and trace where the looseness is coming from. Typically the U-joints in the intermediate shaft wear out and the looseness they produce can be really hard to track down.

I just realized something... wouldn't a test like that be kind of misleading? Since yeah I can pull and push on them but in truth the car puts WAY more force on them than I ever could, when making turns at speeds higher than 10mph. It's just like what the mechanic told me about the bearings "well if the wheel rolls freely with no objections, your bearings are fine." and I'm thinking to myself, well, bearings are made to handle the ***** a driver hashes out on them, and more importantly the vehical's weight.

I dunno, forgive me I guess I'm just lery about these mechanical things, of a big scale like this anyway, especially when it narrows down to suspension, something you put your trust in each time you drive a car. Though I will conduct these tests anyway and do my best to get you the most accurate answer in return.

[Zero10]

If you can find a way to apply a more realistic force to them, then yes, you can get an indication of when these parts are failing farther in advance, however it is very difficult to do in practice. That is why these tests will only tell you when components are worn out, not when they are just starting to go.

As for the intermediate shaft, it is before the power assist, so the test is accurate.

[Ez-Bone]

Originally Posted by Zero10

If you can find a way to apply a more realistic force to them, then yes, you can get an indication of when these parts are failing farther in advance, however it is very difficult to do in practice. That is why these tests will only tell you when components are worn out, not when they are just starting to go.

As for the intermediate shaft, it is before the power assist, so the test is accurate.

Alright and I just talked with the dealer here and he says to just bring it to him and he'll show me what to do exactly and what I need (Don't worry, not paying the 'Porsche Price' for the services, he was actually nice enough to offer allot of services for free and some discounts ) to get. Meanwhile he did ask me how I wanted the tracking setup and I was wondering, what toe should I get for front and rear?

I hear rumor, positive front toe improves turn-in at the sacrifice of straight tracking, how true is that? I mean, it sounds logical with how the front (tops) wheels would lean inward and their bases (where they meet ground) are out

[curveto]

I hear rumor, positive front toe improves turn-in at the sacrifice of straight tracking, how true is that? I mean, it sounds logical with how the front (tops) wheels would lean inward and their bases (where they meet ground) are out

I think you're confusing toe with camber (in your description) but less toe in (i.e., approaching 0 toe but still negative) will indeed make a rear drive car want to initiate a turn more easily. It will also introduce tire wear. Overdoing it will cause you to need to keep both hands on the wheel lest ye have the car dart to the L or R un-commanded.

Rear drive cars (like the 944) usually need at least a little negative toe in the front. Front drive cars can be set up with more positive toe.

In a rear drive car, slop in the suspension will introduce (positive) toe (wrt the front suspension) when the car is moving forward (no brakes). The opposite will occur with a front driver. As the wheels pull (vs. drag) they introduce a dose of negative toe. Thus the difference. Braking loads change things in (what you should now see as) in obvious manner.

My (ITA) CRX (race car) has positive (static) toe. Quite a bit. My (daily / autocross oriented) 944 was, err... is set up with very slight negative toe (up front) with the aim of achieving near 0 toe under heavy braking. It turns in quite nicely. Not so much aggression that it's a ***** to drive on the street but quick initiation when autocrossing nonetheless.

Negative toe in the rear will tend to make the car more stable under braking. Positive toe in the rear will tend to make the car less stable. Rear toe also influences how the car behaves when you pick the throttle back up just before the apex (of a turn) ... along with lateral load and relative F/R distribution when doing so.

My car has a good dose of negative camber (both ends) and some pretty heavy caster (front, of course). The car routinely kills the inner half of the rears first (from camber). Followed by the inner half of the fronts (from a mix of camber and toe).

I haven't bothered checking tire temps on my 944 since (these past few years) I've chosen to focus (exclusively) on the torque applied to the nut behind the wheel rather than hardware tweaks. Routinely spanking cars that should be obliterating me tells me it's working.

JR