I'm getting a significant vibration that seems to be speed related - it happens at about 80mph, and perhaps slightly more when I'm accelerating rather than coasting/backing off.

It seems to be coming from the front rather than rear of the car.

My first thought was wheel balance, but I had the front wheels re-balanced and it's still there.

I did change the front right wheel bearing recently, but suspect this is OK as a) I believe it would cause problems across the speed/RPM range if it was at fault, and b) I had the wheel off again to check it, and it seems properly seated etc.

Any ideas as to how I can track down the source of he problem, and if there's a good way to check the bearing?

 

Could be one or more of the following, ball joint, strut, wheel balance. Jack car off ground support and grab suspect wheel at 12 and 6 and or 9 and 3 o'clock position and push/pull and see if you have movement. If so then inspect first two above as someone else is flexing suspect wheel.

 

It could also be the shimmy problem.

http://forums.pelicanparts.com/porsc...ml#post5715334

+1 on checking the wheel for play that Campbelljj suggested.

John

 

Might be time to get my hands on some string, spirit levels etc and teach myself wheel alignment

 

OK some additional info, after another quick run:

the vibration seems to happen when the car is turning slightly left, but not dead straight or slightly right. If it's not exclusively under those conditions - around 85mph, turning slightly left - the difference between vibration under those conditions and same speed but dead straight or steering right is so great that what's left is hardly noticeable.

 

I had this problem on my Dodge truck. Yeah I know. But the thing is, I took it to a Firestone dealership and the spun the front wheels and their machine was bucking around due to the side wall separating from the core. The tire in question had 5 years on it (not too many miles) and that's when you can start seeing problems with this type of issue. The tire was a Goodyear Wrangler and the tech had worked for Goodyear previously and said they had a lot of returns on this brand and model of tire. I don't know what you're running but consider this as a possibility. If your tires and wheels are not staggered (different size front vs rears) perhaps a quick rotation of front to rear and recheck to see if the problem is still there. it's a quick way to eliminate the wheel/tire. Good luck

 

Wouldn't hurt to check the wheel balance as well. I had a wheel vibration which only took place at a 10mph range after 60mph.

 

I had to take my car in 3 times to get a good wheel balance. It takes a good machine and a good tech (who cares) to get it right.

 

go even faster.

 

Got the truck back from installing new Firestones and it rides like a new car. The old Goodyears had a lot of tread and no weather checking but they were separating from the core. I only offer this to point out that even though tires look ok, you could be chasing a "wild goose" looking at other stuff. If you can find a friend with a similar car willing to swap wheels for a check or rotate your wheels front to rear (assuming they aren't staggered) you can better isolate where the problem may lie.

 

Most likely wheel balance. Had the same problem some years ago ,changed bearings ,joints and the vibration was reduced but still there. Then balanced the wheels 2 times and it didn't go away.
Finally i changed the wheels also because they were looking very bad and put new tyres on and had them balanced and also balanced on the car, no vibrations at all now . I think the balancing on the car did the trick because not only the wheel gets balanced but the wheel along with the hub and disc so it eliminates any kind of vibration.

 

If you get vibration under load and less while coasting and you feel it in you butt. You probably need CVs. Not just service the ones that are there because the ***** will have worn groves in the outer housings. If you can feel it it's to late to save them most of teh time. If you you take them off and they have don't have much signs of wear, an indication you are extremely sensitive, you can turn them around so the load in the other direction and on a surface not previously used. Axles used to be relativity inexpensive though so you may find it's easier and more cost effective to replace the assemblies as it's about 25% the labor compared to recondition.