Idler Arm Bushing and Trans Mount Tips
 

Just did these two jobs on my 91 300e, had some tips that may save some time for others. I found conflicting advice in my initial searches for both of these jobs.

Transmission mount - I saw a lot of people with the later model w124 running into problems removing the 19mm nut on the mount. There is just not enough clearance between the flex disc and mount to fit a normal box end wrench. Some advised removing the flex disc which is a lot of work! The best advice I found was to either buy a stubby thin 19mm which is nice if you have that luxury. Or you can take a 19mm box end and grind it down a bit, and also cutting it in half, which is what I did and it worked great. A 12pt box end is preffered for tight access. I actually ruined two wrenches as I did it with a 6pt first, which didn't work well. Would have been a 15min job had I known this beforehand.

Idler arm bushing - this was another job with a lot of conflicting advice which threw me off. The bolt is very long and hits the exhaust before it can be removed. Some advocated dropping the exhaust, cutting the head off the bolt, and reinstalling it upside down. Some were even removing tie rods lol. All bad advice lol. All you have to do is push the lower bushing out, then push the upper bushing out as much as you can and you will be able to easily remove the bolt without doing any of the shenanigans above. Then when you reinstall the top bushing only do it halfway so you can reinsert the bolt the same way, from above like it should be. :)

thanks for bushing advice,any special tool for bushing?

Nope. They easily tap out if you can catch the side of them with a flat blade screwdriver and mallet/hammer. It's easier to pop the lower bushing out from above and then get push the upper bushing from down underneath.

Haven't driven the car since idler bushing replacement, but I look forward to a big improvement.

Thanks for the tip!