98 Box with bad vibration at speed

[dghii]

Currently in the process of working on a 98 Box with 117K miles I picked up last fall. The car runs and drives great around town but if I accelerate and drive about 65--75mph, the front end shakes to the point I will not go any faster. At 60mph and under it is fine.

The tires are older but have even wear. I know that at this age and mileage, all suspension pieces are suspect. I have no desire to completely redue the front suspension but am trying to figure out what is the most likely source of the vibration.

I have had the car on a lift (4 point, wheels were suspended) while I replace the motor mount. I pried around the ball joints with and examined pieces the best I could but found nothing of note.

With the car on the ground, pressing on the each quarter panel does not result in any noise or excessive rebound. Turing the wheels while stationary results in no noises.

I am wondering if strut bearing could be the culpret.

How else can I troubleshoot the front end and identify the offending part(s)?

Thanks!

[j.fro]

Rebalance the front tires, preferably by a shop with a Hunter Roadforce balancer.

[dghii]

I'm ready to try that as it would be an easy repair. Been working overseas almost nonstop since I bought the car. I'll be home in a couple of week ready to get after it.

I think I'll take the wheels/tires of my other Boxster and see if problem goes away.

[dghii]

Finally got around to addressing the noise and vibration issue on this car. I replaced the struts and suspension end links and all of the noise and drivability issues were resolved.

I really don't know what the main problem was. The end link boots were torn (top and bottom) on both sides but seemed to move freely. The struts looked ok but that doesn't mean anything.

Botth line. Car drives very nicely now!

[Whippy]

Cant believe you'd go to the trouble of all that before balancing the wheels first and throwing each wheel into a bath of water to check for alloy kinks or cracks!


Glad you're sorted though!

[dghii]

You'd have to have heard/felt the issue. No way it was the wheels out of balance. I have another boxster and still didn't bother swapping fronts.

Beside the high speed shaking (you could hear it as well as feel it), I had a ton of noise over bumps at slow speeds.