replace these motor mounts?

[domchang]

could you all take a look and see if this motor mount on a 1975 450SL need replacing?

the one pictured is the right side motor mount, or what I believe to be the motor mount, as seen from the rear.

the one on the left is in similar condition.

thanks in advance

dom

[MikeTangas]

Looks like a sub-frame mount. Was that picture taken with the front wheels off the ground? If not take another with the wheel off the ground so we can better see if the mount is separating (it does look separated to me). Your chasis should have 4 mounts, 2 each side, for and aft of the spring, I believe.

[domchang]

I'll try and get the pics this weekend, subframe mounts....oh well.

[JimF]

motor mount from my S500 with 98K miles. It ain't pretty but it's a lot better than yours.

It's collapsed so it's no longer a mm; the engine is riding on the frame. What can't be seen is the fact that is about 1/2" to 3/4" shorter than a new mm.

[psfred]

Dom:

The picture is of a subframe bushing and it is shot. Replace all four (big pain in the butt as they go in from the top, I think, like a 115 chassis). Replace the motor mounts, too, as they are very likely shot as well, and the engine will be sitting too low -- my 220D AC compressor was knocking on the fender when I replaced the subframe bushings!

You will have to elevate the car on jack stands NOT under the subframe, then remove the bolts on one side and lower the subframe on a floor jack. The old bushing may be stuck, be prepared to have to pry them out. Lubricate the new ones with silicone spray or dishwashing detergent (NOT oil) and slide them into the space between the subframe and the frame. You will get new "nuts" with them (the little metal tab sticking out of the hole in the frame above the bushing) and new bolts.

The first side is easy. The second side will require a substantial prybar to force the frame down far enough to get the old bushings out and the new ones in. You can remove all four at once if you have a cradle for your floor jack -- the engine and transmission are attached to the subframe, so be carefull -- you can make a real mess of things if you lower them too far. One side at a time is safer for you and the car. Keep your hands OUT of the space between the subframe and frame, please!!

Peter

[MikeTangas]

Just looked at the "extra" book I have that covers 116's and 107's shows the replacement to be as Peter described. Even though there are two per side, it almost looks easier than the mounts on the 108 because the mounts appear shorter and only have the center bolt.

When I replaced mine (see DIY section) I used a 3 foot pry bar which gave enough leverage to do the job single handed. I only tightened the new mount snug to allow a little extra movement for the other side. Once both mounts were in then I torqued them to spec.

Also, as Peter said, do not lift the car by the axle carrier (front sub-frame) to take a picture of the mounts. You will have to lift it at the jack points so the weight of the engine, wheels etc are carried on the mounts. You will then see how bad the mounts are.

Check out the sub-frame mount article in the DIY Section for a few more how to pointers, while not directly relating to your car, there will be some similarity.

[domchang]

thanks very much for all your informative replies....however, I believe this job is definitely outside my comfort level and meager technical expertise.

but will now be able to correctly describe what I want done to the car to a mechanic....

thanks again

dom

[revray]

Aloha Dom,

I have the same situation as you describe, and wanted to follow up with you. Did you ever have the work done? Was your description of "sub frame mounts" accurate when you went to the shop? How much did you pay for the work to be done?

Thanks,

[domchang]

the car those "sub frame mounts" were mounted in was totaled in an accident....she never had a chance.

dom