Well, I finally changed the rear diff mounts in my car. It was labor intensive (but, I loved every painful minute of it). However, if you do not have the special tool needed, forget it!!!Pay somebody to do it. While I was "down there", I also noticed the need for new exhaust hangers, which were done at the same time.
I do not know if it is my idea but, the new diff mounts are a marked improvement in the road feel of the car. I am happy with the results but, let me give you this warning, this job is NOT for everybody.

I need to do the same to my 88 300E. What is the "special tool" that you refer to, and what kind of cost am I to expect for the parts?

Hi E!
The tool is called the sub frame bushing tool. You pull the mounts from the subframe. You can get it from http://www.************************ or http://www.baumtools.com. I did not see it @ Mercedesshop. They are not cheap! Between $100 - $110 plus shipping. I got the one from Baum tools because it was about $10 cheaper and they had in stock. Performance was on back order but I think performance's is better (from their catalog picture). You also need a torx 12mm, I think.
The actual rear mounts are about $10 a piece from Mercedesshop. You need two. There are also two mounts that go on top of the differential (easy to change with no special tools) but, they usually don't go bad. Mine were not bad.

This does improve the feel of the car and yes this job sucks! Every customers car that I've done this on notices a difference. The bushings seem to come out easier if they have been bad for a while and beating aroung a little bit.Congrats on a finished job! Brian

Thanks shooter. BTW, I forgot to mention that I was quoted $300 for the job before I decided to do it on my own. I am sure prices may vary but, I like to work on my car anyways, not to mention the $avings!!!!

Just when you thought this thread was finished...

The mounts on my w124 300d have been clanking around for two years. I have the new mounts and I may get new subframe mounts too. Couldn't I just beat them out with a mallet and centerpunch?

Also, what is required to make the tool for the subframe mounts? I know I sound cheap, but I can replace all the coolant hoses for the price of two tools that I'll never use again. Anyone here done the rear subframe mounts and live to tell the story?

Thanks!

El Cheapo
 

Brother of The Benz. jrd
I too hate to spend for a tool that will be used once and then lost in the caverns of my tool chest.
When changing rear suspension and sub-frame bushings, I used 1/2" drive sockets with all thread bar through the middle, flat washers, nuts and I had a torrington bearing for the turning friction, a receiving tube on the opposite end to press the old bushing into.
I've seen the picture of Performance Products tool and it looks great and expensive.
Good Luck to a very hard job.
Happy Trails Beep Beep from The Spiderman in Houston!!!

If you have a tool that works well for the diff mounts or subframe mounts, do you have a picture so that I can assemble one?

Let me make sure I have the right idea here:

It sounds like the tool is a threaded rod, with two sockets on the rod with the large openings facing each other. This is sandwiched between two washers and this is in turn sandwiched between two nuts. Between one of the nuts and washers there is a bearing to allow the nut to turn without turning the entire assembly such that turning the nut squeezes the two sockets together. This doesn't sound quite right.

What size 1/2" drive sockets were needed, and what size washers? Any particular length of threaded rod?

It sounds like the car needs to go up on jackstands with the rear suspension hanging freely, then unbolting the mount bolts (27mm?). Does the new mount then go onto the subframe, or up into the car? All I see is a plate with a bolt and a rubber pad sandwiched between.

I understand the floor jack goes under the differential (how cruel). Do the jack stands go under the rear jack pads? Never had to elevate the rear before.

Look forward to hearing from you!

jrd,
well let me describe the tool (which is very simple). Like Donald mentioned before, if you can make it, all power to you.
It is a big bolt, around 8-9 inches long with two parts than screws into the bolt. One is shaped like small cup (like the tool you use to make holes for a door knob, I tried to use that too) and the other one is like a thick washer (half inch thick) which is the same diameter as the actual rear mounts. If you can find the thick washer of the same size, it may work for you. I could not find it.
As far as the actual job, you can use jack stands under the rear jack pads, a jack under the differential, loosening of the exhaust system (good time to change rubber hangers) and unbolting the THREE differential mounts (the one on top should be good). Make sure you have all the tools before you start. Once the differential is loose, you can manipulate the differential with your hands, BECAREFUL, it is still connected to the transmission, flex disks, center joint, etc. and there is very little clearance.
Good luck