Symptoms of knackered front top mounts?

[Ziggy]

As in the subject really! The front top mounts are about the only thing I've not replaced recently, suspension wise, so I'm wondering if I should! I've still got a bit of vibration going on, seemingly through the whole car, at motorway speeds (anywhere between about 70 and 90). I've not had my rear wheels re-balanced recently, but I'll be getting my new wheels on soon so I'll see if that helps.

Failing that, could it be the prop centre bearing?

Any ideas appreciated!

[Simon13]

my money would be prop centre bearing, front top mounts are good as good really. I haven't heard of them failing even now

[Martinaston]

Jack the front up so the wheel is just off the floor and use a lever (jack handle) under the tyre to see if you can bounce the whole wheel and suspension leg up and down slightly, if so the top mount has too much play in it. it's normally more noticeable at slow speeds (10-20 mph) over rough tarmac.

As for the shakes, if it's the centre of the dash that shakes at speed it's probably your rear tyres need re-balancing due to wear.

[TVRTASMIN]

On the subject of front top mounts. What are the best to buy, i was told E46, but maybe this is a rear application only.
So what goes on the front?

cheers

ian

[Simon13]

standard ones are good, u can by eccentric ones from BMW but they are over £100 each and unless u are really really serious about cornering or track work then i wouldn't bother

[Ziggy]

Jack the front up so the wheel is just off the floor and use a lever (jack handle) under the tyre to see if you can bounce the whole wheel and suspension leg up and down slightly, if so the top mount has too much play in it. it's normally more noticeable at slow speeds (10-20 mph) over rough tarmac.

As for the shakes, if it's the centre of the dash that shakes at speed it's probably your rear tyres need re-balancing due to wear.

Sounds like topmounts are unlikely then... There's no issues til much higher speeds than that & it's over any surface.
The shakes seem to come through the wheel for a couple of seconds, then through the seat for a couple of seconds, & repeat & repeat &... it's weird!

What's the classic symptoms of a dead prop centre bearing then?

Cheers guys

[rickk]

My experience with a prop center bearings are that they usually manifest themselves at much lower speeds too, a low thumping sound around 20-30mph and a fast vibration at motorway speeds.

Your issue sounds like just wheel balance, wouldn't worry too much about it.