[abeardo83]

Hi all, just wondering if you can shed some light on something for me.
This is my first E92, so you'll have to excuse the daft questions...

I've noticed a rattling sound coming from the rear when going over bumpy roads. I got the car up in the air, and there's a plastic cylinder covering the top of the shock absorbers that is loose (in so much as it moves up and down the length of the shock absorber piston when the wheels are in the air and the piston is exposed).

I think it's part #2 on the below website - does anyone know what it is, or how i can secure it down? Makes my car sound like a rattly old can!

http://www.realoem.com/bmw/enUS/show...diagId=33_1927

Thanks
Andy

[ajsalida]

It's a dust boot to protect the shock shaft. It is supposed to fit snugly over the bottom of the bump stop. If yours is damaged and/or the bump stop is gone or deteriorated, you'll need another. They are sold as one part, stop + boot:

https://www.ecstuning.com/BMW-E92-33..._3.0L/ES58963/

[abeardo83]

thanks - let me guess that I can't do this easily??

[ajsalida]

Originally Posted by abeardo83

thanks - let me guess that I can't do this easily??

Well that depends on what tools and experience you have. First I'd see if you can just press the boot back onto the bump stop. If that won't work or the parts are old and rotted, you'll need to replace them. You need a boot there to protect the shock rod form dirt etc. Short term you could just trim it off or duct tape it to the bump stop if it is still there.

It is pretty easy to replace with new as far as these things go. You need to jack up/support the rear, remove the wheel, remove the top shock mount from inside the trunk (after removing carpet etc.), drop the shock rod out into the rear fenderwell, remove the pieces above the boot/bump stop, take out the old stop/boot, and replace parts and reassemble in the correct order. Use the diagram on realoem.com to reassemble.

[abeardo83]

i think most of the parts are a bit past their best to be honest. I've got all of the tools that i think i'd need (from memory, the coils aren't on the shocks, so there'd be no need for a coil compressor.)

I've replaced the coilovers on an S2000 before, but it was on a workshop ramp. I'd be doing this on my driveway.

Seeing as it'd only be the top fastenings on the shock, there wouldn't be a need for an alignment straight away, would there?

(thanks for your help so far, btw!!)

[ajsalida]

Sure happy to help. No need for alignment or to remove the springs. Use jack stands to support the car. You'll need to compress the shock rod down into the wheel well by hand after detaching the top to remove the rest of the parts. I would think about doing the following, replace bump stops + boots and top shock mounts on both sides. Inspect the other parts while you are in there, like the cup washer that sits over the bump stop, and the rubber gasket nipple thing (the black part in the diagram). Replace anything that looks worn or rotten. The stock top mounts are too soft and get worse over time. Monroe makes a cheap firmer replacement, see a thread on it here:

http://www.e90post.com/forums/showthread.php?t=1145344

Finally be very careful about reassembling in correct order, note it upon disassembly and refer to above diagram in case anything is missing. It is a very easy job but people seem to screw it up often. If you don't do it right the top shock rod can pop up through the trunk area, or get yanked through the hole into the wheel well. Either case is bad not to mention dangerous for handling and control as the shock is not working anymore with the rod thrashing around in there not hooked to anything.

[cdgatti]

just to add to aj's comments I believe the work to rebuild/replace the mount pieces is easier if you take out the shock absorber, and once you have the top of the shock disconnected so you can compress it, you are just one bolt on the bottom of the shock from taking the whole thing out anyway.

[Three_thirty_I]

In an unexpected twist I am in the same boat - just by random chance I noticed that the right rear bump stop on my E90 is looking rather sad. Now, with the car's age, regardless of the low mileage (just went over to 78k km yesterday), I can only think that like most rubber bushes etc, they start to become more fragile and prone to falling apart. Anyway, this is what it looks like.



I cannot think that the car's suspension has had any significant impacts, no potholes etc. Some time ago I did however have a slightly harder than normal bump on the way down a pass, and it is possible that this was when it failed since I do recall a slightly "uneven" behaviour from the rear - as if the car veered to one side as it dealt with this bump. The more I think about it, it was quite a nasty and unexpected bump, so it is possible, but then I am shocked that it was yet enough to get to the bump stop.

I have already looked at the DIY for this and it seems very straight forward - there's a good DIY on Pelican Parts and I found one here too, DIY: changing out the rear struts. Found this too:

[ajsalida]

Those bump stops are just foam, and not very good foam at that. They rot pretty quickly and are toast usually long before other rubber parts go bad.

[Three_thirty_I]

Originally Posted by ajsalida

Those bump stops are just foam, and not very good foam at that. They rot pretty quickly and are toast usually long before other rubber parts go bad.

Thanks, that was what I was thinking.