chris walrod

I certainly agree. I may have worded this poorly. I should have said "Wheel bearings could likely be a cause of wobble in many other types of cars but it seems as though the 993 wheels bearings are quite stout"

hoggel

Ha! Give the guy a brake.

Fred's 964

I agree this wobble could be caused by several different things. Because of my experience, I suggest you check your rotors for a wobble first, then look further if they are OK. I had the wobble when I bought my 993. After considering all the options, the simplest thing to rule out was the rotors (and ruling them out costs nothing). I used a dial indicator to check the runout on my front rotors and found them to have a .009 variance on the inside and outside surface on the left one and .010 on the right one. Otherwise they looked perfect with little to no wear. The thickness was consistent, but had a definite wobble. (you may call it a warp if you want to.) The old rotors were Zimmermans according to the PO's records. $114 each for OEM rotors from my local Porsche dealer cured the problem. I'm so glad to have a steady steering wheel now. (By the way, I managed to convince my local porsche dealer to nearly match Sunset's price of $109 and I didn't have to pay shipping from Oregon to Florida....)

C.J. Ichiban

on my 993 I had wobble when my wheel weights fell out, misbalancing everything. recently I got new pads, wheels and advan 048 tires and on the way home from the track yesterday got a bit of a wobble at low speeds but it went away completely at high speeds. taking the car in monday for a brake fluid flush anyway- I'll have them do the screwdriver test to make sure but suspect I just need to re-bed my pads and get the car re-aligned.

Texas993

Hey CJ,

Look out for Dan while at RUF tomorrow. He is taking his car in to have the MO30 installed.

C4S993

I have steering wheel wobble that starts between 50mph and 60mph. I have had new rotors, pads, steering rack and twice 4 wheel aligned and new P-Zeros. I also have a twitchy rear end in even the slightest rain. It feels like the '96 C4S is struggling with it's 4-wheel drive system and feels like it wants to go out of control and do a 360 even when driving straight on wet roads. 120k on car, no prior hx of ax.

Not sure this matters but I had the clutch replaced a few months ago.

Thanks

RallyJon

If you had a viscous coupling that actually failed (as opposed to the fluid leaking out), it would be locked all the time, which would make handling very strange.

Sounds like a bent wheel or alignment though. How good was the shop that mounted the tires? Did they road force balance them and also check the wheels for true?

niche

I had a similar problem with wobble while braking. Turned out it was out-of-balance wheels.

hn

I had similar issue on my 95 cab. Vibration happened during light braking and randomly on curvy roads. I tried hard braking to clean out deposit but that didn't do much. I installed Chris' urethane arm bushings and it took care of the problem completely. I was skeptical at first especially when I looked at my oem bushings and they didn't look too bad. I guess 13 years old rubber can get mushy with or without cracks.

drivingmydream

My 96 does the same thing. Usually braking from higher speeds though and it is intermittent on my car and it seems to be in the left front. If it was the rotor it would happen more and it's possible the tire is out of bala=ne but since it's so infrequent the bushing sound more like the culprit to me. Is that a difficult DIY job or not? Thanks. Mike

hn

It's not difficult, just lots of detail, dirty work. I spent most the time on the removing the oem front bushings (bigger one) and cleaning up the hats/sleeves. Make sure you mark the casters position and which one is left or right. I didn't mark the L or R and it cost me more time. A short torque wrench would help too. There are some good tips here:

https://rennlist.com/forums/showthre...light=bushings

mleds

I had my Turbos bushings change and it ELIMINATED the wobbles completely... It was a very clean, easy DIY.... because Mr. Walrod did it
Thanks Chris,
Michael

Texas993

The control arm bushings will most likely corrrect the problem. Worked wonders on my 964, my 993 is next for the repair.

Marlon

My black 110K mile 95' 993 did the same thing. Occasionally and at certain speeds. Was the control arm bushings.

shamrock

I have the same 'squeaky over bumps when cold' symptoms. I've not heard of 'sway bar bushes' before .. Do they call em something different in Europe?


I have to say I get confused with different terminology especially when it comes to suspension..