E30 Zone

im getting a severe vibration when driving, it feels like its coming from the back, most of it goes away when im breaking or accelerating and it completely goes away when i turn left around a bend and all the weight is shifted over to the right and it is at its worst when i turn right and all the weight gets shifted to the left. i changed both rear wheel bearings and that didn't fix the problem. when i play with the clutch it feels like the diff is loose and has play in it so ive been told that it could be the diff that is causing the vibrations. does any1 know if this is the cause ? any help would be much appreciated because this problem is really annoying.
cheers

check your front prop coupling - these often split and / or shear the bolts off if not torqued correctly. this gives a severe buttock massaging effect! also, double check all of your wheel bolts

ok ill have to check that out, is the coupling easy/cheap to fix ?

it's an afternoon job. a pain as you'll have to remove / drop the exhaust and heatshields to do it. you should just about be able to see the joint with them in-situ though so worth a look today wjile the sun's out!

i'ed consider checking out the centre bearing too if i was doing this, they often fail too and you could kill 2 birds with one stone.

while you're at it... fit a Z3 shifter and a new shifter knuckle. a days work and the car will feel transormed!!!

cheap and easy if you have a ramp or some good axle stands. the bolts can be a pig to get to and an airpowered wrench is best. you also need to be able to turn the rear wheels to get access to all the bolts.

you first need to drop the exhaust (only from the manifold lower join and push it out of the way), remove the heat shield then the prop is visible, you may also need to loosen the prop coulping nut (found in the middle of the prop where the two pieces join) this wil allow the two parts to slide together and then you can remove the donut easier - note mark the two half of the prop so in the event the two parts must be split you can re join them in EXACTLY the same splines.

I have found this job is best done with a pit, that way you can roll the car forward/backward

good poins there!
if no pit is available, a mate sat in the car to take the handbrake on and off will save a lot of time and backache