chuckactor

OK. After posting about my rough idle problem, I decided to try replacing the mounts.

The car was running fine then all of a sudden developed a very rough idle when cold. When the car is in neutral it is OK and you can feel it slightly in reverse.

After driving around for awhile (20-30 minutes), it usually goes away or is not nearly as noticeable.

The part that was screwing me up was it went away after driving awhile. I had thoughts of the tranny or torque converter grenading itself.

I went ahead and purchased a set of OEM Lenforder mounts from Autohauz. I also bought a Corteco tranny mount from autopartswarehouse. The parts came to about $200.

The job is a DIY if your patient and fairly handy. It took me around 2-3 hours. That includes time spent starring at it and wonder what I did to get myself into this. So here are the steps (sorry no pictures, I was covered with grease):

1) Disconnect the ground on the battery (10mm wrench). The passenger side mount is near the alternator and I whacked a wrench against the battery lead on it and made some nice sparks.

2) Put the car on ramps. If you got a lift, subtract at least an hour..

3) Use a 10mm socket and pull the belly pan and the mid pan off the bottom of the tranny.

4) Use a 13mm socket on a long extension and remove both lower mount bolts.

5) Cut a piece of wood to jack up the motor. I used a piece of 1x6 poplar maybe 12" long. The wood goes in front of the steering rack and against the oil pan. Put the other end on a floor jack. Raise the motor 2-3 inches.

Lets start with the passenger side (easy side).

6) Unplug both airboxes from the grill and lift them out of the way. No need to remove them. You just need some room.

7) Use a stubby (4") long 5/8" wrench to loosen the top bolt on the mount. Yep 5/8"... Get the wrench on the bolt head perpendicular to the motor and whack the wrench with a hammer to loosen it. Trust me you can't get in a long wrench and you have no leverage to loosen it by hand. Unscrew the bolt and let the mount drop.

8) Go back under the car and remove the 2 bolts holding the sway bar on the passenger side. They are probably E12 or E13. All I had was an E14 and it work to get the bolts out. You need to be able to move the sway-bar to make room to pull the mount out toward the front of the car. You can leave the left side and the ends connected.

9) Wiggle the mount out. You may need to jack the motor a bit more.

10) Put the new mount in the way the old one came out. It is a bit tighter fit as the new mount is probably 3/4" taller than the collapsed ones that come out. I left the rubber cover off the mounts. The old ones didn't have one and someone posted that they make the install a pain.

11) Screw the top bolt in. You may need to drop the motor back down a bit to get the bolt to start. Note how the mount has a keying tab. The heat-shield also has a slot in that keys it. Tighten the top bolt with the stubby wrench and a hammer. Torque to spec... whack whack... Leave the bottom mount bolt out for now.

OK.. I will vary the steps a bit from my actual. I got the top bolt of the drivers side out from the top. It was a *****. It required the stubby wrench. The handle from the floor jack and a large hammer. And.. a second person. I held the end of the jack handle against the wrench and my neighbor hit the end with the small sledge. This side is very tight. I think it can be gotten from the bottom easier.

12) Remove the exhaust pipe on the left from the exhaust manifold to the back Y-Pipe. It is only 6 bolts and 2 connectors. Unplug both O2 sensors and use a 13mm socket on a wobble extension or a universal to get the manifold bolts. A 13mm socket will get the middle mount nuts off and you will need a 12mm wrench and your socket for the back clamp.

13) Once the pipe is out of the way, you should be able to get the top motor mount bolt from the bottom. I took mine out from the top but put it back in from underneath the car.

14) With the pipe out of the way, you can get the mount in and out toward the back of the car. There is no way to pass it forward due to the AC compressor, steering lines, power steering pump etc. I starred at this one for awhile before I dropped the exhaust pipe. I was about to drop the steering rack but it didn't look like that would free enough room.

15) Put in the top mount bolt. Again, you may need to drop the motor a bit to get the bolt started. Again the mount and shield are keyed. I used the stubby wrench with another wrench hooked on the open end to lever the top bolt tight.

16) I put the exhaust back together with the motor jacked up a bit. It made it easier to get the manifold bolts. Don't forget to replug the (2) O2 sensors. The front ones wire clips to the heat shield on the mount then the block and back down.

17) Drop the motor and use your 13mm socket on a long extension to tighten the bottom mount bolts down. It might help to get the bolts started before you drop the motor all the way.

18) Put the two bolts back in the sway bar bracket.

19) Put the tranny skid plate back and then the front belly pan section.

20) Reconnect the battery. Start the car and remember to turn the wheel hard left and hard right to kill the ESP warning on start-up. You'll probably get one since the battery was un-hooked.

21) Put all your tools away and grab a beer or two....

FYI, one of my fluid filled mounts was empty and you could shake pieces of rubber out the bottom mount hole. The other (drivers side) sounded half full. The ones I took out were Boge. I still haven't done the tranny mount.

Chuck

loudandheard

Great info, I might want to do this soon too. How many miles did you have on your car?

chuckactor

The car has 118k miles on it.

Now to find the oil leak...

Chuck

loudandheard

Is the oil leak at the front engine or is more towards the rear? You could take off the plastic pans to see where the oil begins to drop. There are a few different areas where you could develop a leak.

These are a few that I have encountered:
Oil cooler
Oil filter housing
Valve covers
Power steering pump
transmission pilot bushing

francoisisp

Great write up.

chuckactor

I just did the oil cooler and filter housing seals today. Actually a pretty quick and easy job. The seal set was around $20. You can do the job w/o disconnecting the coolant lines. The trick is to remove the filter housing so you can move it out a bit to access the oil cooler bolts. No big deal if you have a giant socket. I didn't have the 46mm socket but had a 1-7/8" socket that worked to loosen the fastener holding the housing in.

The old seals were hard and brittle. I gunked everything. I'll check it tomorrow after driving for awhile to see if that got the leak.

Chuck

MoE55

Great post Chuck so I followed your detailed instructions! Got mine done in a leisurely 4hrs. Just wanted to add a few pix.

Saaboteur

Anyone ever use one of these?

http://www.kochtools.com/index.php?p=product&id=77

I picked one up but haven't done the engine mounts yet.

EDgineered

How did that tool work for you, I hope well, I just ordered one...

maverik259

well considering he bolded 5/8" for the top bolt I would be interested as well if this actually fit!

EDgineered

I will update how the repair goes in the coming days as I just got the tool and a set of motor and trans mounts in. The tool is heavy duty and looks built for a purpose. Its supposed to make the job much easier.

http://www.kochtools.com/index.php?p=product&id=77

Went drag racing Sunday with a length of 3/16 chain wrapped over the mount and under the cross member and bolted together. It seemed to work well as a temp fix but had to leave the belly pan off. When I pull out the old mounts out I'm gonna fill them with Urethane #80 like some E55, C32 and Crossfire guys have done.

maverik259

it needed to be chained down? lol perhaps drag racing wasn't the best plan haha

EDgineered

The tool worked great for the top bolts. The tool is very sturdy, once it goes on top of the head of the bolt you can bang it around as you try to stick in the extension and it wont fall off too easily. Keep a coat hanger or wire handy just in case you drop it.

I used a 3/8 in ratchet and two 12" extensions. Once the bolt is broken loose you will need to lift and move the wrench back and add another part of a turn before it can unbolted by hand. It is a tight forearm fit on the drivers side, less on the passenger side, suggest long sleeves.

http://www.kochtools.com/index.php?p=product&id=77

Probably not but somebody has to give you spectators something to watch! lol Plus I love telling my garage queen buddies in my best NASCAR voice "yep, we dun come round turn two n felt something pop, brought her inta da pitz, reeeelized we had a bustit mutr mount, man o man we thought weez wuz dun. We got an ole chain up in der n got dat mutr lockd down and off we went." Then I start rambling on thanking the sponsors and such hahaha

Saaboteur

Did you drop the exhaust downpipe, or leave it in there? I've been fixing to get this job done for a while now, just need to find the time!

EDgineered

Yes, I don't think you can get the drivers side mount out without dropping it.

Taking the exhaust out wasn't too bad. I had to cut the bolt on the band clamp in front of my resonator delete (not sure if stock clamp...) to get it down but the exhaust brackets on each side of the trans and the bolts into the exhaust manifold flange came out easily, but I had also hit them with a shot of WD the day before. Make sure to unhook the O2 sensors and unclip the wires before dropping the exhaust so nothing is stretched. ~2-3 hour job if you have some experience and are prepared.

jack(s)
min 2 jack stands
16mm motor mount top bolt tool
multiple 3/8 ratchets with 12mm and 13mm sockets
two 12" extensions or a few extensions to make at least 18"
3/8 swivel

AMGPirate

Great write up guys! On the C55, when removing the section of exhaust to do the driver side mount, are there any gaskets, hardware I should have on hand for re-installing or is everything I'll be taking apart re-usable?

Thanks!

Saaboteur

I will likely do this job on a hoist at my friend's workplace. I've been underneath my C43 extensively, and the C55 is basically a variation of the same. Wobble extensions work best for the tighter situations I've found.

One of the previous owners of my car cut out the secondary cats and the resonator, but just had the shop weld it all up. This past spring, I had another exhaust shop cut the pipes and add connectors. This way I'll be able to drop just the downpipes one by one, instead of having to drop the whole exhaust.

A quick look at the EPC shows that there is a seal ring between the driver's side downpipe and the other side. However, that same piece on my C43 was metal and I reused it. The bolts and nuts though - might want to take a peek at those to be sure they're in decent enough condition to reuse.

Saaboteur

Here's a screen shot.

gnma

Just got a quote from the dealer of $1,695 to change engine and tranny mounts!! From searching here other dealers are charging a little less than $1K. Will look elsewhere, but I'm tempted to try this myself. I've changed turbos and fuel tanks so I'm quite handy. So if I read the first post correctly, removing the top bolt of the mount allows the engine to be jacked up slightly? I guess both mounts have to have their top bolts removed before jacking the engine? Wish there were pictures in this very handy write-up. Nonetheless thank you for the write-up! Any further help/pics is appreciated!

vin544

How are you dropping he exhaust on the drivers side to do this? Mine looks like it's all one piece from the manifold flange on back. I don't think I can do it that way on my car.

Does anyone have a write up or can point to info on dropping the steering rack? Maybe I can snake it out the front if I can get some clearance. I'm assuming when you drop the rack down you dont have to disengage the tie rods.

greekspec2

I did this without dropping any exhaust...passenger side simple and driver side just disconnect power steering line and fish the mount out no problem

KJI3jflarryfe93

you put URO parts on your AMG?
how do you find them, good or bad?

URO is something very nasty, I would not put these parts on my car.
DP USA = Deutsche Parts USA sold on Ebay are nasty as well!!

cm60k

+100000000001

ZAYED,,

vin544

Well I just finished the job. The passenger side I was able to wiggle out of the front right above the sway bar without removing or loosening a thing. The drivers side I considered removing the power steering hose but it didn't seem that there was enough clearance to get it out so I took the exhaust out, which was relatively easy. 6 bolts, the two in the rear where the pipes come together were rusted so I cut them off with a dremel. The real PITA was trying to get the exhaust back on. The big benefit of removing the exhaust to do the job though was being able to easily get the top bolt out and back in without any acrobatic body gyrations, and the mount just slid out the back nice and easy.