Rear Front Subframe Mounts

[Strife]

I just did one of these, and it was unpleasant, but doable. I soaked the crap out of everything with Liquid Wrench PTFE over the course of several days beforehand, and I think that this helped. The "two-jaw" puller as shown in the MB manual was worthless - the puller screw did an excellent job of lifting the body, that's all. Putting the mount in was nasty -even after the socket was thoroughly cleaned and silicone and GOOP were liberally applied. I tried everything - jacking was not that useful because of the "body lift" problem, and I stacked pennies on each side of my big jack platform to mate with the metal tabs of the mount (don't just press on the rubber mounted center - this is ineffective and may damage it).

What worked best was a C-clamp, tighened one side (again, pressing on the metal tab of the mount, not the rubber), then the other - and a small sledge hammer and a short piece of metal, again, used side-to-side to walk it in. I haven't seen the C-clamp mentioned before.

My mount didn't look bad, it wasn't broken, but the rubber was starting to deteriorate and it was 19 years old...

[el Miguel]

Whew! I dread this job! Good description Strife.
Mike

[Strife]

Additional comment: it was impossible for me to get the mount entirely seated - there was an approx 1/8" gap between the "top" of the rubber and the metal. Other people have reported this also. Driving around for a day cured this. I retorqued it but it was still OK (120NM for the main bolt).

Strife,

I'm doing the rear subframe mounts and having a hard time extracting the old mount due to the body-lifting problem. How did you solve it? I'm thinking maybe somehow bolting an iron strap across the top of the subframe (right above the hole through the mount) so the puller can anchor against the iron strap instead of the chassis. Any thoughts? Also, did you do rear sway bar bushings or control arm bushings?

Rich Mayer
82 500 SL

[Strife]

I think I "dug" it out with a very large screwdriver and LOTS of silicone lubricant, walking it out from one side to the other. I might have even chiseled into the rubber and leveraged it out on the frame lip, as I recall.

Thanks. Do you mean you poured the lubricant through the opening at the top of the subframe? I squirted PB Blaster around the lower edge of the mount but don't think anything made it up there. I will try the prying method. I'm worried that, if the weight of 1/2 the car was not enough, my prying will likewise not be enough. We'll see.

Rich Mayer
82 500 SL

[Kebowers]

Instead of trying the 'factory way' , which works on pristine mounts, use a cave-man approach--simple, direct, no humongous effort required. Simply use your little roto-zip file to grind out all the rubber, then your trusty little 3 corner 'muffler pipe loosener' chisel to cut out the metal shell.

Easy, fast, doesn't risk damaging the housing or ?

OK, I got them both out. On the first, I had the weight of 1/2 the car and pried the thing out. On the other, the puller got it out. Getting the new one in there was a challenge, too. I used a homemade press (angle iron, a 1/2" x 4" bolt, a cross piece to thread into above, and a mess of washers and spacers) to get it in. It took all my air tool had to seat it. I am eager to see if there is any change in handling, height of the rear end, etc. Thanks for the advice.

Rich Mayer
82 500 SL

[smiked1]

I'm in the process of picking up my first SL. I've aways loved these cars, and always dreamed of owning one. This is also the only drop top I knew my wife would love and I could get away with.

I've come over here from the e30 BMW world, so I'm prepared for subframe mount replacement. These seem like a piece of cake compared to BMW mounts. I've read that people have had trouble getting them out. The ultimate cave man way is to put a piece of metal roof flashing above the mount and light it up with a torch. I know this sounds crazy; but it works very well and is extremely fast. If it really lights up, you'll have to touch up the subframe paint, but that's simple.

Someone should probably start making a urethane replacement. A soft urethane bushing does not make the car much noiser, and is very easy to R&R. So much so, you can make it a regular replacement item. Urethane mounts do not require much force to press in and out. It also seems to make the car track much better and feel more solid. Also, in this application it doesn't seem to suffer from squeeking issues. This is the only place I'll use a ureathane mount over factory rubber, for the sole reason of easy replacement.

[Strife]

I found very little improvement compared to changing the front subframe mounts, but the rears weren't really bad, just old, whereas the fronts were anywhere from chewed up and crushed to non-existent (particularly the one where the oil/steering fluid had been dripping on it for several years...).