Ghostrideradv

Hello all. I have a 1999 C2 911. I bought the car a few months ago and have noticed a problem that doesn't seem to go away.

When I hit certain speeds (49-52mph and 69-73mph) I get a vibration/shake in the steering wheel jerking the wheel left and right. When I go a little faster or slower, it goes away. It's present about 80% of the time. 20% of the time its fine and the steering wheel is perfectly smooth. The problem seems to come and go as it feels, but I have noticed that some road surfaces make it worse.

I'm guessing I have a bushing that is worn out. I tried to re-balance the front tires, and then I went and put new front tires on. It didn't help at all. The vibration still comes and goes at different speeds.

Any advise would be appreciated. Thank you.

If this has been posted elsewhere, please link me.

MechanicalEng

Check in the following order: 1 Tire pressures in front tires, 2 check balancing and wheel roundness 3steering rack

kent

also check the front and rear wheels' bearing as well

Ghostrideradv

Front tires are new and air pressure is good. I'm thinking it's something that falls in and out of alignment. In a turn, the wobbling reduces significantly. But when i straighten it out again, it resumes. I think the culprit is some component that when put under pressure seems to align or at least not shake back and forth.

yasuro

i think the lack of pics is messing with the balance and/or roundness of your tires.

ivangene

Have a trustworthy alignment guy look at it.

Could be alignment, bent wheel, tie rod, steering rack, shock, bearing, brake rotor, poor fitting wheel centers, spacers or other things.

Have it looked at and don't just throw money at random parts hoping.

Gl and post resolution

Ghostrideradv

Alignment center sounds like the best idea. No point wasting time and money replacing working parts. I'll update with results.

AndyK

Intresting. I get a vibration from my winter wheels that I don't get on my summer wheels. The center caps are loose and wind up almost falling out when I return from a drive. Could THAT be causing my vibration issues??

I posted a question about how to fix loose center caps on non-Porsche 17" twists, but got no answers. I was thinking of using a heat gun to pry the little plastic tabs out more. Or, using a rubber band to make the fit tighter so the caps will stay put.

ivangene

No - your problem is something entirely differant





winter tires can have flat spots from storage... or maybe the wheels you bought/have are out of round... or the centers are too big....a good tire shop can check them for trueness for little money.

AndyK

Damn, I want a simple solution that solves my problem for nothing! I had the fronts balanced without issue. Usually if the wheels weren't true, they would mention it.

I'm taking the center caps off and going for a ride tonight!

Pac996

There are do it yourself (DIY) pages with pictures for the bearings R&R online here if you want to service them. It didn't appear to be an american style of service by just popping the hub off so give yourself some room and time if you go that way.

Thundertub

This may not be of any help to the questions posed here so far, but I found that spurious front wheel vibrations occurred after a DE event. Why? Because my wheels would pick up glops of track tire goop on the inside of the rim. I don't run track tires. Never have. But many others do, and my tires would pick that up and put little lumps of it on the inside of the rim.
By cleaning off the inside of the rims after an event, I completely eliminated the frequency of tire balancing I was doing. And although those glops attach themselves when the wheels are hot, they pluck right off when the wheels cool. Not saying this is the answer for the OP, but just like leaves in the radiator openings, things happen.

AndyK

Good points, extra goop on the tire = extra weight, causing the wheels to be out of balance. I don't have any goop on my wheels though.

I was having this same problem (vibrations at certain speeds) on my 944. I had the wheels balanced, rims checked, etc. Nothing worked. Then, a genius mechanic took the tires off the rims, and found water (from a lame gas station air compressor) sloshing around in there! Fixed the problem and my 944 was smooth as silk after that, up to 100 mph!

You never know.

Pac996

Since new tires were tried and the same symptom were present I gotta figure it wasn't dirt attached inside the rim or a case of wear making the tires out of round and balance. The only things I can figure hasn't been asked is if there is any slack in the steering. One slight move to either side should have direct and instant results with no slack. If there is a little slack it might also be a case of the wheels tracking on there own in that slack area and highlighting imperfections in alignment and suspension.

I do wonder if you have a bad habit. I highly recommend you never turn the wheels while the car is sitting stationary. Tire belts can be dislodged even if the newer tires aren't as prone to the problem. You can't see the belts are screwed up becuase they are internal. Make sure the car is rolling before doing steering inputs or at least only do a very minor input then roll to get the rest of the turn in. Messed up belts will exhibit what you refer to. No turning the wheel the contact patch is stationary.

Ghostrideradv

To be a little more clear on the issue, I'm not turning the wheel when the vehicle is stopped. When I drive down the lane and feel the shaking, I can swerve in the lane and as long as I hold the car in a turn in the lane, the shaking will stop. It's not that I can get it to stop by wrenching the wheel left and right before I take off from a light.

The weird thing is, sometimes I don't feel anything at all, then a minute or two later, it will come back.

It's gotta be something that has some free play in it, and turning the car in a turn eliminates the free play enough to stop one of the wheels from shaking left and right.

I don't know what it is. I can't imagine that this problem is unique.