Rear banging / noise

craigbeal

Member
Hit a hard bump the other day and since had a terrible knocking since… had a quick look at the top mounts to find this:

Drivers side:

IMG_0671.jpeg

Passenger side with noise:

IMG_0672.jpeg

Looks like the strut has failed, so will be new struts and top mounts (with reinforcement plate).
 
To be pedantic it is the top mount that has failed. but obviously you'll be fitting all new stuff anyway.
Don't be tempted to use Meyle HD mounts! They have no raised rubber section so the cup washers impact directly on the metal sleeve in the top mount and make a hell of a racket.
Lemforder are the ones to get. You'll see on the rubber that they have a small rubbed down bit which used to say BMW. OEM supplier.
 
Looks like the struts are 2021 sach but the top mounts might be original? Because of this if I get it all torn down could I get away with new top mounts and the struts be ok?

Rear springs are all brand new and the fronts seems to have high spec springs and adjustable shocks which the prev owner said he had done.
 
craigbeal said:
Looks like the struts are 2021 sach but the top mounts might be original? Because of this if I get it all torn down could I get away with new top mounts and the struts be ok?

Rear springs are all brand new and the fronts seems to have high spec springs and adjustable shocks which the prev owner said he had done.
Given the reasonable costs of Sachs replacements I think I'd replace the pair.
New bump stops and dust covers too?
I just priced up Sachs rear shocks, Lemforder top mounts and a Febi Bilstein bump stop/dust cover kit that does both sides on Autodoc.
Currently 41% discount on the app and the lot comes to £133 including delivery.
 
It looks like he fitted a stance ultra plus kit on the car.. but I suspect he didn’t bother with new top mounts hence them failing…?

Not sure if he’s swapped the struts for non stance as well (he did mention something about not being happy with the rear suspicion when he swapped) so makes sense he maybe went with the Sach again but kept the Stance springs and adjusters.

I will order the Lemforder top mounts now and see what the state of play is once I get the wheel and strut out and order if needed.
 
Got the shocks off today, seems he fitted washers to both struts but they are super thin so under stress it’s blasted the washer off on the strut poked through.

Also no bump stops or covers fitted so these have been ordered along with new top mounts

IMG_0676.jpeg
 
IMG_0676.jpeg

Seems a washer was added on both struts but paper thin and so under stress have broken off and then the strut poked through.
 
Were there not cup washers both top and bottom? The lower one would prevent the strut coming through as the whole lot bolts up tight to the shoulder on the strut.
 
Nope didn't seem to be strut washers either!!

Ive now had BMW cup washers arrive along with new top mounts and reinforcement plates too.

Also stripped the brakes down and the handbrake mech whilst it was up and wheels off.

Will check the front suspection install now too !!!
 
Back
Top Bottom