Tale of woe with the 123 motor mounts
 

RE: a 1985 300TDT (123.193) For the life of me I CANNOT remove the motor mounts on this car. I have read all the previous threads on this topic and still can't understand how you remove those damn screws. The outer 6mm (I think) allen screw comes out with little effort. On the underside, the large 10mm allen head comes out easily enough. The inner 6mm allen head (closest to the engine on both mounts) is impossible to get access to. I don't get it. The engine carrier arm is in the way - even with the engine raised as high as it can go. You can't fit a conventional L-shaped allen wrench in there, not enough torque and the hole this allen bolt sits in is too deep. Plus the bolt has been in there for twenty-years now, and full of crud which makes it REALLY hard to get a good bite with the allen bit. How the hell do you do it?

On the passenger side, the turbo charger is constantly in the way. I think the previous owner may have tried the engine-side bolt a few times - it appears to be stripped. I suppose I'll have to drill it out from the underside.

Yeah, this is a real PITA -- not much better on the 220D, either!

You have several options. First, go buy another 6mm allen and cut if off some (take the burr off the edges before you use it) so you have some more room. This is the easiest and simplest option, and usually works. You will need to access the bolt from underneath, usually.

The next option is to remove the engine carrier -- lift and secure the engine, then remove the four nuts on the engine side and pull it off. Big hassle, but at least you can get to the screw that way.

Finally, if the screw is so badly stripped you can't get it out, you will have to take a Dremel or similar and cut the head off with the engine carrier out.

Needless to say, SECURE the engine so it cannot slip and fall on you while you are doing this....

Peter

search for 123 motor mounts tools
 

I'm too dumb to link to a previous post, but this one has a picture of the tools I use to replace motor mounts.

You need to raise the engine higher, or reposition your jack. I know exactly what you mean. Also, try to use a 3/8" ratchet with a hex socket. That's waht I used. I probably looked at it for 10 minutes before I figured out exactly what I needed to do. Try to move the jack more to the driver's side, that will allow you to get that side way up in the air. Then do the same for the other. You may have to do a little of experimentation to get the right spot, but can be done.
Thanks
David

I agree with david on the 3/8 ratchet/ hex socket combo. You will also need to remove the bottom bolt on the engine shock to give the engine more room to raise. What I did (3 weeks ago) was place a nice 4X4 log under the oil pan and a jack under that. I raised the engine ever so slowly until I had just enough clearance to work on that bolt. By doing this, I didn't have to remove the engine support brackets. There will be just enough room to get the socket and the ratchet in there! Word of advise.........Don't bolt everything down on one side until BOTH mounds are positioned in place. It will be a PITA if you do (ask me how I know). Just keep the screws lightly threadeaded so you dont have the mounds moving around, but DO NOT tighten them until you have both in place. Make sure your car is secure before you get under it and have the engine lifted! :D

Good Luck!

how long did it take you?
 

Thanks for the advice. It was my friend's car. I couldn't finish it today so I put everything back together again so he could drive it. I'll attempt it again at a later date. Just out of curiosity, how long does it take to replace just the two motor mounts? I've got five (almost six) hours into this job and I'm still not done...

About 2 - 3 hours.

I did it on a lift, but really, I didn't even use it much. I just used to get the big bolts from the bottom. I'm spoiled. usually, I always use a lift for motor mounts, but these were best done on the ground obviously.
Thanks
David