I own a 1992 300E. Is there a special tool or a special way to remove the top bolt on the left motor mount? I cannot get to the bolt with a regular wrench or socket. Thanks for your help.

I could not get that big bolt out either on my 96 SL320, what I had to do was remove the bracket from the block, then remove the bolts from the mount on the frame, at that time you can remove the entire assembly. (after supporting the engine of course) once the bracket and the mount are out, you can put the bracket flat against the concrete and stand on it, using a large socket you will have enough torque to get the bolt loose. When reinstalling you should put the mount in first, line the bolts up underneath, put them in, but don't toque them down yet. Install the bracket back on to the block, if you can not get the bolt hole to line up with the bracket use your tire jack from the trunk, put the botton on the fender (metal part) and the part of the jack that goes in the hole against the block of the engine, this allows you to move the engine back and forth in the bay and get the bolt hole lined up. Don't torque the bolt down yet. The only bolts that should be tighted and torqued at this time are the ones in the bracket on the block. After your mounts are replaced, get underneath your car and loosen the bolts on the exhaust hanger that mounts to the side of the transmission. remove all supports to the engine (jacks) and start the engine letting it come to normal operating temprature. The reason you do this is to relieve stress on your exhaust. The mounts, when failing, actually cause your engine to lower in the bay, putting new ones in will raise it, that is why it is important to allow these mounts to set in at normal operating temp. Once the engine has cooled down a bit, then tighten the bolts on the bottom of the mounts, the big main bolts, and lastly re-tighten te bolts on the exhaust hanger. Check your rubber exhaust supports at this time to ensure they are ok because as the exhaust lowered you could have broken a few, also check your flex discs on the drive line. Good luck!
Best Regards,

__________________
Brian W. Heitman

www.MBCA.org/northtexas

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There are not much room on the left side, but you can do it.

Jack the engine a little to take the weight off the engine mount
Spray some liquid wrench
Remove top bolt with short box-end wrench

Jack