OM617 Motor Mount DIY - PeachParts Mercedes-Benz Forum

rg2098 · #1 05-09-2006, 09:28 PM

A member asked me for a write up so it is. If anyone could take photos while using these steps as well as the exact fastener sizes please forward them to me to add and complete the DIY. I have found this the easiest method after doing motor mounts a few times.

1) Remove air cleaner assembly and unclip fan shroud (don't need to remove)
2) Remove center bolt from bottom of vehicle that mounts the engine to the mounts
3) Using a light vice grips to stop the shock from turning, unbolt the engine shocks from their top brackets.
4) Remove the engine shock upper brackets
5) Jack engine up using a board across the oil pan until most of the engine shocks are out of the hole only leaving the slim post above (you may be able to use a socket extension to push it down and "hook" it under the arm)(you will see what I mean)
6) Using the large hole uncovered by the engine shock mount, remove the inside motor mount bolt followed by the outside.
7) Slip in a new mount and assembly is the reverse of assembly.

NOTES:
-Clean out the allen head bolts well and use a hammer to fully seat the socket otherwise there is a chance you round it out.
-Don't jack the engine up without removing the mount center bolt and disconnecting the shocks from the brackets.
-Don't replace the trans mount while the motor mounts are loose. (don't ask how I know)

pawoSD · #2 05-10-2006, 12:58 AM

What do you do if you rounded out the central bolt inside one of the mounts (passenger side in our case)....this happened on the '83 as I was attempting to loosen it.

Is there a "best way" to tackle/get that bolt out???

JimmyL · #3 05-10-2006, 01:11 AM

Do NOT forget to undo the accelerator linkage from the firewall. We don't want that bent now, do we..........

I just had my motor mounts replaced, and I had one of the bolts rounded. The gentleman pounded a star socket into it in order to extract it.
Then he was nice enough to reuse said rounded bolt...

pawoSD · #4 05-10-2006, 01:22 AM

A star socket? Would this work well?? Or would there be a better method to removing it....

rg2098 · #5 05-10-2006, 06:52 AM

Quote:

Originally Posted by JimmyL

Do NOT forget to undo the accelerator linkage from the firewall. We don't want that bent now, do we..........

I just had my motor mounts replaced, and I had one of the bolts rounded. The gentleman pounded a star socket into it in order to extract it.
Then he was nice enough to reuse said rounded bolt...

I didn't have a problem with the linkage left on. There is enough slack and movability. It just takes a second to remove the long shaft between the firewall and valve cover and you can remove it if you want for piece of mind.

300TD · #6 05-10-2006, 07:19 AM

Don't forget to loosen the fan shroud to allow the engine to be jacked without pushing the fan against the shroud. Also, be careful that you don't bend a shifter rod (like I did) when jacking the engine.

Make sure to clean the inside of the bolt heads really well before trying to loosen them. They are usually packed with grime and the hex head does not seat well enough to work. Rounded hex heads are a REAL pain to remove!!!

vstech · #7 05-10-2006, 09:55 AM

I got a pretty good digital camera and several web sights to host pics, so I will digitally catalog my progress. I should start this saturday, maybe sooner!
And I think after I get the vehicle supported really well, I will pressure wash the underside of the vehicle. so don't be suprized when you can actually see the transmission mounts and bolts!
John

pawoSD · #8 05-10-2006, 09:58 AM

I never undid my throttle linkage or shifter linkage or fan shroud when I did mine, and it came out fine.....

I only jacket it up enough to just barely slide the mounts out though.

rg2098 · #9 05-10-2006, 11:06 AM

Quote:

Originally Posted by pawoSD

I never undid my throttle linkage or shifter linkage or fan shroud when I did mine, and it came out fine.....

I only jacket it up enough to just barely slide the mounts out though.

Its easier to access the inside bolts with the engine high, the shroud does need to be unclipped because the fan will catch on the upper lip. The trans doesn't move that much when jacking up the engine and the shift rod is in no danger.

JWJ · #10 06-22-2006, 05:37 AM

So the left and right engine mounts are identical?

TwitchKitty · #11 06-22-2006, 10:08 AM

A good first step is a trip to the steam cleaner or pressure washer.

A mention of the transmission mount is in order.

tangofox007 · #12 06-22-2006, 10:18 AM

Quote:

Originally Posted by rg2098

Its easier to access the inside bolts with the engine high, the shroud does need to be unclipped because the fan will catch on the upper lip.

And if you continue to raise the engine after the fan hits the shroud, something has to give. How difficult is it to remove two clips from the shroud? No more difficult than disconnecting the accelerator linkage, which is also a very smart thing to do.

AYSCII · #13 06-22-2006, 12:13 PM

Hey, I'm in Raleigh NC also.... I just replaced the motor mounts on my 83 300D weekend before last. Yep, they are both the same. I reused the original heat shields, also of note, I had to cut down a L-shaped allen wrench to fit in there... I only removed the engine shock on the drivers side, as I remember.
Call me voice if you need anything... 919-291-4195 cell.

#14 10-03-2006, 11:04 PM

I changed mine mounts on Madeline tonight. I just removed the air cleaner, unclipped the radiator fan shroud, and unbolted the engine shocks. Accessing the inside bolt of the two smaller hex head bolts on the IP was a stinker. Next time I think I will cut the bend off of a 8mm and 10m Allen wrench and use than on a ratchet so that I have a long narrow tool to access the sockets. The job took about three hours by myself. With the modified tools that I mentioned I probably could have cut 40 minutes off the job.

Nordon · #15 05-20-2007, 12:28 AM

Replaced mine on my 240d tonight, I should put pics up of my drivers side mount. Terrible. I was unable to fit the heat shields back in, because I didn't unclip the shroud or remove the shocks, so I couldn't get the engine high enough, looking back its probably not a good idea, but mounts are cheap if they go bad and my car drives like new now... Definitely difficult to get to the hex under the IP but everything else went rather smoothly.