I'm now gearing up to swap my struts with rebuilt ones. As we know all to well, the upper rubber mounts for the rear struts are NLA so it's necessary to reuse the old ones. I have 4 altogether, 2 are on the car now and 2 from a parts car. One of the parts car mounts is in excellent condition, seems virtually new. The other is substantially compressed, at least 5mm thinner than the other. Moreover, it's compressed unevenly. I'm not sure what the mounts on the car look like, I'll find out soon enough.
So, the question is, which of these to use? If one (or both) of the mounts on the car look newish then obviously I'd just put them back on. What I'm guessing though is that I'll have a grab-bag - 1 excellent, 1 poor and 2 somewhere in between. I'm concerned that if I pair the good mount with a compressed one then the left and right axles will be slightly different heights. After all, the suspension has no way to compensate for an effective difference in strut length (which includes the mounts). Is this so? And if it is, does that mean I'm better off using whichever 2 mounts are closest to each other in size? Comments welcome, thanks and cheers,
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[sidebar comment: tcj on this board is able to rebuild the front strut mounts as well replace the front bumpers/stops. He can also provide new front strut cups. PM him directly if interested.]
I've had this same issue on my full hydro Euro 500SEL. I had a selection of mounts in various conditions. I opted to go for the two that best matched each other.
do it in two steps.
1. mount two with the same height
then check if the car stands on the same height left+right
2. if uneven you can use the different rubber mounts to compensate that.
regards,
Thomas