Constant vibration at high speed 987 Cayman

[Gerber1]

At motorway speeds my Cayman has a very subtle vibration, not really a problem but enough to annoy me. But as you go faster it becomes more evident and is worrying enough to make you slow down and as a result I can’t do any track days or autobahn driving until this is fixed.

I’ve done the basics and fitted new tyres and ensured the wheels are actually balanced perfectly and attached to the car correctly. The vibration also remains even if I depress the clutch so it’s not the flywheel.

The only thing I can think of is I have had new front brakes (discs, pads etc.), the parts are genuine and I fitted them myself with no problem. I’m thinking they could be out because there is a minute shaking of the wheel but this does not correspond with the massive vibration through the body of the car.

The other thing is I had new exhaust bolts fitted and the mechanic caught the drive shaft which has removed the protective coating, would this make the car undriveable at high speed?

I’m tempted to refit the front brakes but I’m not sure what I could do different as I cleaned all the surfaces before fitting?

Any ideas would be appreciated.

[nickfrog]

If the vibration is proportional to road speed it may be a wheel bearing ?

[Gerber1]

Would a wheel bearing cause a vibration? There is no audible warning that anything is wrong with the car, and no grating / grinding like is usually associated with a wheel bearing.

[boxsey]

When you changed the brake discs did you have any problems getting the old ones off the hubs?

[Gerber1]

Yep, they were bds to come off.

Had to use a mallet and hammer evenly around the edge of the disc in order to get them off.

[boxsey]

Gerber1 said:

Yep, they were bds to come off.

Had to use a mallet and hammer evenly around the edge of the disc in order to get them off.

I thought you might say that. It makes me wonder if the bashing might have caused some damage to one of the suspension components so it might be worth getting each wheel off and having a look around?

There's an easy and kinder way to remove the discs. Each disc has a couple of tapped M8 holes in the hub. You put M8 bolts in those and wind them in with a wrench. The bolts make contact with the wheel carrier and press off the discs with no commotion.

[Gerber1]

boxsey said:

I thought you might say that. It makes me wonder if the bashing might have caused some damage to one of the suspension components so it might be worth getting each wheel off and having a look around?

There's an easy and kinder way to remove the discs. Each disc has a couple of tapped M8 holes in the hub. You put M8 bolts in those and wind them in with a wrench. The bolts make contact with the wheel carrier and press off the discs with no commotion.

Although I appreciate what you’re saying, I really wasn’t that rough and I was careful to take the disc off uniformly. If you think about it the suspension is designed to take the weight of a car going round a corner at 170mph, the force of which is surely more than me hitting the back of the disc with a rubber mallet.

Either way any potential damage that would probably be impossible to pick up with the naked eye.

What’s annoying me though is although I can tell its dependent on road speed I can’t tell if it’s coming from a rotating mass or not.

olly22n said:

My cayman had warped discs. they were 2 year old, 2k miles old genuine porsche items, fitted by porsche to a 14k mile car.

However my vibration was worse under braking, and you could feel the discs catching when you came to a stop.

So you had a vibration when not braking, like me? Mine does not get worse when braking but I can occasionally hear the pads catching/brakes squealing when going very slowly even when I am not braking. The pistons were fully wound back prior to reassembly and with the car jacked up I can turn the wheels relatively easily by hand.

[boxsey]

Gerber1 said:

Although I appreciate what you’re saying, I really wasn’t that rough and I was careful to take the disc off uniformly. If you think about it the suspension is designed to take the weight of a car going round a corner at 170mph, the force of which is surely more than me hitting the back of the disc with a rubber mallet.

Either way any potential damage that would probably be impossible to pick up with the naked eye.

What’s annoying me though is although I can tell its dependent on road speed I can’t tell if it’s coming from a rotating mass or not.

It might not be visible damage as such. It could just be that the tracking (toe) has been knocked out on one side. Clipping a kerb is enough to knock out the tracking and cause vibration. Hitting the back of a disc that initially refuses to budge could do the same thing. Getting the geometry checked would be a good place to start. I'm only putting this suggestion up because you mentioned the vibration started after changing the brakes.

[nj1052]

Its worth checking for bent inner wheel rims, front and back. Even a slight bend can cause this.

Cheers

[Digga]

Jack up car and grab wheels at 12 and 6 o clock to check whether there's any flex from the strut top mounts. Can cause vibrations either under very (I.e. Track not road) braking, or at very high (illegal in UK) road speeds.

[Gerber1]

As the steering wheel definitely shakes at 60mph and above then I think I need to resolve that in order to eliminate the front axle.

With the car jacked up, how freely should the wheels turn? Mine show some resistance and you can hear the pads against the discs but I have repeatedly pushed the pistons back and after the first use they go back to how they were.

I have noticed that the front brakes can get rather hot even when I've not really used them.

Is it worth getting the discs skimmed to eliminate any run out even if they have only done 5000 miles?

[88racing]

Sounds to me like your front callipers need a strip down clean and refurb.

[selym]

same issue, albeit on another car, and I think I've narrowed it down to play in a front lower control arm.

[Gerber1]

So I jacked each corner of the car up and span the wheels, 3 of them span in an identical manner (although with some resistance as shown).

The drivers side front brake however didn't spin much, I've got two quick videos here.

Drivers side
https://www.youtube.com/watch?v=p20pn-A2p3I&fe...

Passengers side
https://www.youtube.com/watch?v=me2KvnN78n8&fe...

What do people think? The car is under warranty, perhaps Porsche will replace the calipers? I don't think I am outside of their terms and conditions by changing the brakes myself?

[lordlee]

You can't really tell much from the video. When did the vibration start? After mechanic hit driveshaft? After you did the front brakes?

[Gerber1]

To be honest I couldn't say, but I'm pretty sure it was after the brakes were fitted and bedded in.

I think a driveshaft would only cause a vibration if it was properly imbalanced or damaged rather than just knocked with a drill, where as a minor imbalance of the discs would cause the steering wheel judder I am referring to.

I'm going to take the car to a respected garage for their opinion.

[lordlee]

I'd think it wax either those pesky vibration shims or a disc not properly seated.

[Bennachie]

Suspect warranty has gone. Who changed brakes? Are they factory parts etc.. etc.