87 190e: Upper shock mount repair- Bumpa lumpa bumpa - PeachParts Mercedes-Benz Forum

haasman · #1 12-09-2003, 02:14 AM

Bumpa lumpa bumpa ... the sound kept getting worse.

I figured replacing the original shocks (219k miles) would cure it .... it did not.

Every time taking a left turn (unweighting the left suspension) I heard it. Then the sound could be heard on rippled roads. Driving me crazy!

Not a heavy loose metal on metal component sound. Hard to at first determine exactly where it was coming from, front or rear.

Now I knew the upper shock mount had a small crack in its rubber but when I replaced the shocks (in a hurry) I didn't turn the mount over to check.

I finally bought a new mount, un bolted the three 13mm mount bolts, took off the 17mm center nut, raised the car with a floor jack to keep the left front wheel on the ground but just enough to remove the rubber mount. Easy to do, no more than fifteen minutes in and out.

If your upper rubber shock mount has even a little crack in it, beware you are headed for the bumpa lumpa bumpa .....

Inspection underneath revealed that half the mount was simply pulled away from the inner metal piece. Thus the surrounding rubber was softening the pounding from the upper shock piece.

FastLane sells the Strut Mount for $34.20 (Retail $43.00)

Installed the new one and now quiet. No more bumpa lumpa bumpa sound AND the front end feels much more compliant going over bumps and the like.

Ahhh ....

Love these cars,

Haasman

haasman · #2 12-09-2003, 02:21 AM

Strut Mounts

wjm · #3 03-29-2004, 03:35 PM

How had was it to replace the shock mounts?

haasman · #4 03-29-2004, 04:01 PM

The hardest part is getting the old shock mount off the top of the front strut (shock absorber). You have to compress the strut downwards enough to get the color off the strut top. Depending on how new your struts are (and thus their pressure) The mount is held into the body by three 10mm nuts. The top of the strut is held into the mount by one 17mm nut.

I was told to jack the car using the jack point right behind the front wheel, but not to lift the wheel off the ground. Worked well.

Haasman

chazola · #5 03-29-2004, 06:06 PM

I tried to replace mine but couldn't get the big main nut to budge.
grrr! The 3 smaller ones came off with no problem. I've had the parts for about 3 months now so I'll hopefully get my tech to replace them this week as they creak and the rubber is quite badly cracked.

haasman · #6 03-29-2004, 06:38 PM

Two things about the big nut:

-The center of the strut has to be isolated with an allen that I believe is a 10mm or an 8mm (sorry I don't recall which)

-Since the big nut is down into the metal cap and its sides prevent one easily getting an open ended wrench on it, the best thing to use is a closed-end 17mm.

If your upper mounts are torn, the replacement is worth the effort.

Haasman

Freestyler · #7 03-30-2004, 01:47 AM

My w124 fells like something is loose in the front suspention. (Bumping feels somewhat dampened - not metal against metal) And it is very distinct on rippled roads -but everything seems nice and tight when i check it.
Could 'worn' shock mounts cause this behaviour? -even if they are not cracked?

Freestyler

Greg in Oz · #8 03-30-2004, 01:48 AM

Quote:

Originally posted by haasman
Two things about the big nut:

-The center of the strut has to be isolated with an allen that I believe is a 10mm or an 8mm (sorry I don't recall which)

-Since the big nut is down into the metal cap and its sides prevent one easily getting an open ended wrench on it, the best thing to use is a closed-end 17mm.

If your upper mounts are torn, the replacement is worth the effort.

Haasman

The allen key actually needs to be 7mm. This I remember because the most time consuming part of the job for me was grinding an 8mm allen key down to 7mm (which I did not already have and did not want to have to go out and find). The allen key is to prevent the strut piston rod rotating when loosening the 17mm nut (with ring spanner/wrench).

As Haasman states the rest of the job is easy at about 10-15 minutes per side. Just be sure as he states to raise the front of the car such that the tyres are still just in contact with the ground to prevent the control arm dropping and allowing the spring to escape when the top of the strut is released.

wjm · #9 03-30-2004, 08:01 AM

Thanks guys,

This clears things up!

Willy

csnow · #10 03-30-2004, 11:17 AM

"The allen key actually needs to be 7mm. This I remember because the most time consuming part of the job for me was grinding an 8mm allen key down to 7mm (which I did not already have and did not want to have to go out and find)."

Not sure why, but some struts have 7mm tops and some have 8mm.
7mm is not a common allen key size, and many sets do not include it.

chazola:

If the nut gives you trouble, you can use vise-grips (or a pipe wrench) on the piston (below) to immobilize it, then you can put a socket on the nut. If you place the vise-grips high enough, any marring of the surface would be above the range of travel. If you are replacing the struts, it does not matter.

GregS · #11 03-30-2004, 11:42 AM

I don't see how you get the mount off the strut rod? Once the nut is loose, and you raise the car a little, does the strut drop down enough to slip the mount off of it? This seems a little hard since the mount has to come off from underneath the fender, and the rod is sticking through it. Its not like you can just push the strut rod down with your hand to get the mount off of it.

Greg

csnow · #12 03-30-2004, 12:39 PM

"Its not like you can just push the strut rod down with your hand to get the mount off of it."

Actually, you can. Not as hard to compress as you might expect.

haasman · #13 03-31-2004, 12:22 AM

The trick is to get the strut compressed enough to quickly lift the mount off the end before it tries to shoot up.

If you can have someone hold the strut down while someone else takes the mount off, it is a lot easier. Just watch everyone's fingers. Can create a nasty pinch.

Haasman

wjm · #14 04-09-2004, 08:45 AM

Will be attempting the strut mount replacement this weekend.

One more question.... does the strut itself always want to be in the extended position? That is, if you push the strut rod in, does it want to go back out again, or does it just stay in place?

If so, wouldn't it be better to undo the strut mount bolts first (especially the center one) before jacking the car up so that the strut mount is compressed when starting?

Thanks!

Willy

csnow · #15 04-09-2004, 10:03 AM

"One more question.... does the strut itself always want to be in the extended position? That is, if you push the strut rod in, does it want to go back out again, or does it just stay in place?"

The strut wants to extend, but you can force it to retract with your hands. Remember, the strut does not support the weight of the car, the spring does that.

The strut is the thing that keeps the springs from getting loose at full extension, so you do not want the spring to be 'hanging' on the strut. For removal/install, what you want is for the strut to be almost fully extended, retracted perhaps an inch.