From about 75 to 90 mph (not been [much] faster than that) I'm getting a vibration "wave" that appears to go through the car at about 3 second intervals. I still have some issues with the wheel balancing (I'm waiting till I can afford new tyres and a trip to Watford) but Im not convinced that the vibration is un-balance induced. Has anyone experienced a similar problem or perhaps offer some advice as to where to start looking.

Any advice will be gratefully received and a Happy New Year everyone.

Marc-H

I reckon balancing'll fix it.

Hi there! Have had similar problem with my GS300 Mk2. However the brake discs were warped and during the change I have found that a caliper slider had siezed. Having stripped it I found the sliders worn and corroded so I will replace them this weekend. Worth a look to see if yours are siezed or worn. If so the caliper 'wobbles' while resting against the disc during normal running.

As for wheel balance, I have long thought that no-one in the UK can balance wheels and I am having the same trouble. You mentioned Watford? I went to a company in Watford recomended on this site and they made things a lot worse than they were. I had new continentals fitted at ATS in Bow, London and the guys did a fair job on the balancing. They were just NOT quite right, bringing in a slight vibration/wobble from 68mph onwards. After I had them balanced at Watford they wobbled from 55mph and more pronounced.

I am going to approach a local Porsche dealer re wheel balance. I have been told by one of there techs that they spin the wheels up to a higher speed that enables them to 'fine tune' balance a wheel!!??

Check out your discs and calipers to see if they are OK anyhow. Then yo wil just have to see if you can get the wheels balanced for high speed driving etc


Regards
MC

Did you check your balljoints?

These need to be replaced relatively often. After replacing these on mine, steering was much more firm.

I had to change the rear tyres recently and after putting up with this vibration problem for many months (luckily I don't do many miles) the problem is now solved. I'd already been through the motions of balancing - and re-balancing - but never any real improvement, so as soon as I realised the problem had disappeared, I went bak to the tyre fitters and looked at the old tyres which looked to be somewhat oval. Hmmm.