R171 Rear suspension replacement

[Blobcat]

Further to my front suspension change:

R171 Front suspension replacement

Front passenger side spring broke at the bottom (don’t they all…) :rolleyes: I've ordered the struts and springs - £301.31 all in for 2 x Bilstein B4 Shock absorbers and 2 x Febi Bilstein Coil Springs - although not here yet… Wanted to check if I need the top mounts as well and as Theo is...

forums.mercedesclub.org.uk

Today I tackled the rears

Overall much easier than the front as no scary spring compressors required

First thing is to find the suspension top mount in the boot… there is a pre-formed cutout in the carpet (see red arrow below)



Just cut enough of the tabs around the circle so you can fold it back to access the top mount



You then need a 17mm feed through socket and a 5x8mm “socket” to hold the centre.



I then undid the 17mm nut, removed the large washer and rubber top mount



Next chock the front wheels, jack the car up, remove the road wheel, use a couple of axle stands as well as a trolley jack to keep safe.

A couple of 10mm nuts hold the plastic undertray to the lower suspension arm, you can then unclip it so you can access the lower nuts.



There are just 3 nuts to remove - 16mm on the shock, 13mm on the anti-roll bar and 21mm on the lower hub



The 2 smaller bolts have E-Torx heads (E14 and E12) and the hub bolt is 22mm.

With a second jack and a block of wood you can lift the arm to take the tension off the bolts. The 2 small ones slide out easily enough. The hub bolt required a little persuasion…



New v old



Surprise surprise drivers side rear spring broken at the bottom…

 

[Blobcat]

Lowering the jack, then releases the shock and spring with zero fuss

I scrapped and wire brushed the lower arm then primed and sprayed it with tough black.




Refitting is the opposite of removal…

Remember to fit the inner top rubber mount from the old shock to the new one

I took the top rubber spring mount out, cleaned it then fitted it to the new spring, then aligned the bottom of the spring on the bottom arm - there is a cutout for the end of the spring to seat in correctly.



By adjusting the height of the jack under the lower arm you can get the bolts to slide back through.

I tightened up the 17mm top nut after fitting the upper top mount rubber and washer.

I also liberally applied ACF50 to the suspension



The passenger side spring wasn’t broken!



I replaced it anyway so all 4 are now new

Cleaned up the passenger side same as drivers side



It was a bit more fiddly getting the hub lower bolt out on the passenger side but not overly challenging.



All back together, wheels torqued back on and a drive around the block to test for noises - all good