Rear shock tower mount: what breaks?

[MichaelP]

I'm getting nasty clunking noises in our '91 318i convertible from the left rear wheel on hard cornering -- which sounds like it must be a "broken" shock tower mount. Thing is, the PO had both sides replaced less than 9,000 miles ago at the dealer ($338 :eek:). The replaced parts were the guide support, the gasket and the self-locking nut, parts numbered 7, 10 and 11 in this diagram (link to realoem):

I've never had a mount break before, so I have a few questions:

1. What "breaks" exactly? The guide support looks ok from inside the wheel well.

2. What parts should I order to R+R (see above link to diagram)?

3. I am considering ordering the Ireland Engineering mounts instead of the apparently weak BMW ones. Considering that there are different shock mount part numbers listed for the convertible than for the coupe or sedan, does anyone have experience with this? Yeah, I know that I should call IE and ask, but I'm looking for independent thoughts first.

[swiss318is]

the mount has two parts a rubber part and a metal part. the rubber is into the metalmount and it happens that they loose the connectivity. so, the rubberpart is loose and the damper moves around and the whole thing makes noises.

338$ ? man it should cost around 70$ all parts and 15-20min of works!!! dont go there anymore!!!

to look if it is really the mount, you have to remove the carpet in the trunk.. then move the car up and down... you can easely see if it is broken or not! the dampers will come out of the mounts..

part number 10 and 11 ar not necessary if you already have a mount in your car..

[swiss318is]

by the way.. i have the oem parts in my stock bmw and they work fine... they are not weak, they are soft (comfortable!!).. the IE parts are harder and it could be that you will have a higher noiselevel in your car..