deliriousga

Found the problem...see the end of the thread for report.

I'm getting some shaking when I take her over 80mph. Here are the things I'm doing/looking at, but is there something else I should check?

1) I checked my front spioler because it looked loose. I replaced two missing speed nuts and re-fastened everything properly under the clips so I was hoping it would go away, but it didn't.

2) I'm going to get the tires balanced.

3) I grabbed the front tires when it was off of the ground and shook them vertically to see if I need ball joints. They both move about 1mm total back and forth (can barely feel it), but I don't know how much vertical play there should be at the wheels if any on the 928.

4) I'm checking the CV joints and replacing/re-packing the boots.

Thanks!

Jim_H

Does it go away at 90?

Probably the balancing will fix it.

goliver

If the car has sat for a time the tires will flatspot until the tire is warmed up after driving for awhile.

bigs

I guess I'd even check something as simple as making sure all lug nuts are tight.

worf928

Is the shaking more noticeable through the steering wheel or the seat bottom? Does the shaking coincide with any noises? If yes can you localize the noise source?

AO

Make sure the valve stem is opposite the painted lugnut. I just learned this one recently...

hinchcliffe

Grab the top and bottom of the wheel (while in the air of course) and shake. Top hand into the car and bottom away, back and forth. If there is any play it may be the wheel bearings. You can tighten the collar that holds the wheels bearings in place and see if it goes away. The hard part is getting that damn center dust cover off.

deliriousga

Jim H: It lessens at about 115 but doesn't go away.

goliver: How much driving does this take? I drove for 1 1/2 hours out to a retreat to make announcements then 1 1/2 hours back after being there 1 hour. It was shaking some before I put her up, but not as noticable.

bigs: Will check tonight.

worf: I'll check on my way home and make sure before I post that. Please check back some time after 8:00 eastern and I'll make sure I post my findings.

Thanks for the great stuff guys!

goliver

It shouldn't take that long if it is flat-spotted from sitting. My guess would be wheel balance. Not sure if 1mm defelction is good on the front though. I had mine in the air to replace a atf return line that was leaking on top of the TT. Mine don't move at all.

Mark

wheel balance - or PERMANENT flat spot from a skid/slide/brake lockup! (BTDT!!!)

Also - you might want to pull the wheels - maybe some kinda crud/mud/dirt from the road has stuck itself to a wheel and is causing a bad out of balance.

heinrich

John were you chewing gum when you inflated them? ... I'd say balance; worn tyres or worn suspension. Should cover it.

Tom. M

One more thing to check are the tie rods...Mine had worn at the steering rack connection and I had a vibration around 35 mph..that would go away if I went faster or slower than that speed. put her up in the air and move the wheel by grabbing front and back of wheel and try to make it turn..(make sure the steeing wheel doesn't move) and sure enough...good 1/4inch of play on the one side. Ends up the ball cup end of the tie rod was shot...

Good luck..
Tom
midlman@rennlist.net
89GT

mark kibort

sounds like balancing or out of round tires. they can be balanced, but still have vibration at certain speeds.

see if the vibration goes away with controlled braking, and braking while turning. could be wheel bearings, but that is a more high frequency vibration, like hummmm.

mk

deliriousga

Dave C.-All of the vibration is in the seat. The steering wheel is not pulled at all, but you can feel the vibration just because the whole car is shaking. It's starting at 80 and is worse from 90-110. Shakes enough to make your back itch like sitting on a lawnmower.

I'll check the tie rods and see what happens with the braking. Don't think it's permanent flat spots...ABS so no skidding.

Bill Ball

Wheel out of balance, if from the front, should shake the steering wheel. From the rear, the whole car. I had a rear wheel off one ounce and the car vibrated at 120.