After reading every thread that I could find, I optimistically attempted to tackle my motor mounts, 1977 300D, non-turbo.

After about 1.5 hours, I surrendered. I was unable to budge any of the mounting bolts. Any tips before I dip my 300D in WD-40.

JCD

JCD,

I did this job recently on my 1982 240D and it took quite a while as I had little knowledge of what to expect and ran into a lot of trouble with access to the fasteners that hold the mounts to the subframe. For what it is worth, I will review my experience for you.

First, I put the car up on ramps to I could get all the way under it. I did the driver's side first because that side is the hardest and had the mount that was really broken in half. I "learned" that the procedure should have you take out the 10 mm Allen head screw from the center of the mount first. This releases the engine from the mount, and you can jack the engine up to get the little sheet metal cover loose. You have to jack a 240D engine up over an inch as the sheet metal cover is stamped into a shape that makes it hard to get out from under the strut from the engine block. With this little sheet metal obstruction out of the way you should be able to get some pretty good access to the heads of the 6mm or so Allen head screws that hold the mount to the subframe. The inboard one was particularly nasty as it could not be reached from above. The passenger side one was a dream as it could be reached (no turbo, like your car) from above, on both 6mm screws.

The driver's side remained a pain mostly because of the inboard 6mm screw. I ended up taking the mount that grabs the bell housing off and replacing that too as it was restricting the "upward mobility" of the engine as a whole. By the way, I used a hydraulic jack to move the engine, with a few 2"x4" stubs on the jack between the oil pan and jack. The center support or what ever it is called that grabs the bellhousing had to be replaced too as oil leakage from the rear seal just ruined the rubber. That was around $18 and is very simple to remove and replace.

Putting it back together is a little trickier as you have to get the threaded hole in the strut from the block to line up correctly with the mount so you do not cross thread it. I did this by inserting the center 10mm screw in from the bottom first. I got the screw started in the strut and then stopped and moved on to the other ones while I could still rotate the sheet metal cover out of the way. Then I aligned the cover (it has a small ">" mark that aims forward) lowered the engine and tightened the center screw.

Once I got access to the screws, I got them to break free without adding any thread lubes or WD-40. I bought tools at Sears that let me use my larger ratchet wrench (1/2") with a 10mm and 6mm hex bit (straight) sticking out of the end, and this gave me the leverage I needed to get the job done. That inboard one on the driver's side was not accessible using this tool and I had to grunt that one off with a regular Allen wrench. I may have found a position I could add a cheater (6mm socket and extension bar), but I do not recall that. Anyway, it broke loose and actually seemed to be "less tight" in there than the others.

Good luck, and the use of Comet or some abrasive cleanser as a grip enhancer for the Allen wrench in the capscrew is a good idea. You do not want to ruin the screw head or you will have real trouble getting them out. Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Jim,

Thanks for the reply. I have been able to loosen all but the inbound engine side fasteners.

Question before I make the plunge. I am a little concerned about replacing the mounts and changing the alignment of the engine relative to the drive train. Is it recommended to change the trans mount or make any other post engine mount install adjustments.

JCD

JCD,

I did not worry about drive train alignment since I only did one side at a time, and the mounts are kind of soft and had good fit ups to the bolt holes. I figured the alignment could not vary much if only loosened up one side and then the other, and the engine mass would kind of self align as long as the mount fasteners fit up ok.

I did replace the center mount to the bell housing like I said, and that thing is more of a snubber than real mount. It was, as I said, ruined by having oil nearly dissolve all the rubber of the mount. When I put that one back, I kind of guessed at where it was supposed to be, as it is not a compression mount at all. It has a clearance all around it, except where the molded rubber "wings" get captured/clamped at the outer edges. I installed it hard up against the bottom of the bracket it goes in. Seems ok (almost 3K miles, no wierd motions or noises, so I assume it is ok). I thought this was the transmission mount but I do not think it is, I think the tranmission mount is farther back, and I did not replace that.

On my 240D I could even get to the passenger side inboard mount from above. I think you have to play around on the driver's side to get access. Once you get access, it breaks free relatively easily, but you only have a few degrees of travel before you encounter an obstacle and have to find a new position for the wrench. It really helps to get those shields off first.

Keep at and good luck. Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Jim,

I was able to break loose all of the fasteners. The 1977 300D must be configured differently than you're's as the driver's side is much easier than the passenger side. However, with a myriad of tools, I am sure that I will be able to remove all of the fasteners.

One question. The center fastener, accessed from the bottom, I believe a 10MM hex.....does it screw into the mounting bracket that comes off of the motor. Just wondering, before I disassemble and replace.

Thanks so much for your help.

jcd,

Yes, the strut coming off the engine block has a tapped hole to accept the 10mm socket head capscrew that goes in from the bottom/center of the mount.

Maybe the 5th cylinder in the block changes the way the parts fit relative to one another, but getting those covers off the top was the key for me.

Mine went together a lot easier, partly because I got used to the position on my back under the car, but mostly because I knew what was happening next. Good Luck, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

:p :p

Jim,

I thought so......I like to know "what attaches to what" before I disembowl anything.

I'll try to get the job done tomorrow. I'll post any tips that I come up with.....if I am still alive.

Really, up til now it is a pretty easy job, the only challenge is patience.

JCD

Jim,

I have been able to remove all but one of the capscrews, top 6MM on the passenger side. However, I cannot get the engine to lift.

I also removed the bracket back by the bellhousing. It seems that when I lift the motor as prescribed, I lift the whole car. Did you find the motor mounts "stuck" and if so how did you get them loose???

Help, my wife is going to kill me if I don't get this done soon.

JCD

Is there a little shock absorber beside the mount keeping the engine from lifting?

Sixto
91 300SE
81 300SD

Thanks for the help.

No, I am replacing the shock as well, it is off.

? ?
JCD

jcd,

It is possible the whole mess is kind of stuck together, but it is more likely you are not lifting the engine enough.

I had the car on ramps, and then put a couple 2"x4" stubs between a hydraulic jack and the oil pan on one side (the side I was going to work on).

The other side was not unscrewed, and the way the engine mount came free was by tilting and lifting it. And, yes, it did start to lift the car up a little as well. Is the mount still down hard, or just captured by the strut from the engine block? My mounts were very easy to get loose but a real pain to get free, the distinction being once I got the three screws out of each mount, they could be moved around on their base, but not removed as the strut sticks down into the mount an inch or so and you have to lift the strut up and out of the recess in the mount to get the mount out.

Hope this helps, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

I had one mount fully unscrewed and the other with the bottom 10MM off and the outboard 6MM off. I also had the mount at the bellhousing off and the motor shock.

When I jacked it up, I could jack it up 2-3 inches "the whole body" with no movement in the mount.

The mount is down hard as a rock, held down by the mounting bracket that comes from the block.

I am still at a loss and close to taking it to a mechanic.

JCD

I replaced one motor mount. Jim Smith's help was invaluable.

His instructions are right on the mark. My only shortcoming was.....you need to jack the living daylights out of the engine. Once you have jacked it up higher than you ever thought you should, it will be just a little short of enough.

Also, doing one side and then the other is the hot setup. Loosen the 10MM capscrew on the side you're not replacing, to just about out. The place the jack and the 2x4's under the side you are replacing, with all of the screws out, then jack it up until you can pull out the mount. Take out the mount and replace it and then repeat the process for the other side.

If ANYONE!!!!!!! ever has a hard time with this, please e-mail me and I will help you as best I can.

PS,,,,,Jim Smith is the guru of motor mounts.

JCD

jcd,

Glad to hear you got the job done, and using this forum turned out to be of help to you. That is what this forum is all about, sharing our combined experience to make these machines last longer than even Mercedes intended when they built them. I have had a lot of help since I joined, so feels good to give something back. Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Jim,

Again, I appreciate your help. I'll tackle the other one next weekend.

You are my "new best friend"

JCD