Best approach for engine mount replacement? '87 300D
 

I've read a bunch of threads about replacement, but still have a few questions.

Some mention needing air tools for replacement. Should I even try it without them? I have everything like that at my CA house, but I'm in OR for the next few months and the vibration is getting worse.

I'm assuming car on ramps and jack lifting the engine with a block or wood under the oil pan is the standard way to get them off? Are there any particular tricks for alignment or access to fasteners to make the job easier? Torque on the bolts? I have a copy of the FSM but no index to find the sheets, so if someone knows the document number, I can pull it up...

I've replaced many a mount on other cars, and they were always straightforward. Am I overthinking/over-worrying this job?

Thanks!

personally, when i change mounts, using a cherry picker type hoist to lift the engine as high as the trans tunnel will let you is the option I prefer.
I have never changed them on my 87, so can't advise on the use of air tools.

Yes, way double over thinking it-no air tools needed, fact I don't even own any and I've done bunches of these.

Break the top bolts loose on both mounts, the two down the top can be backed out almost to the point of removal.

Jack stand the car on its front jack points.

Break loose both of the lower bolts.

Using a floor jack and a 2x4 or 2x6 5 to 6 inches long to cushion the oil pan, ideally, your board should extend past the pan so the vertical load of the pan bears on the board, and you're not just pushing up in the center of the pan. YOU WANT THE LIFTING PRESSURE DISTRIBUTED BROADLY ACROSS THE PAN. Raise the jack to meet the pan and strategically place your board. You now can remove the lower bolts and GENTLY raise the engine. The left one can almost be done from above, the right one will require jacking the motor until it hits the tunnel and stops. Swip/swap in the new ones, START ALL THE BOLTS FIRST BEFORE LOWERING THE MOTOR, gently lower the motor, tighten it all down,

Job done.

MB has posed all the older car service manuals on the Startekinfo site. Here's the link to the 124.

http://www.startekinfo.com/StarTek/outside/12264/?requestedDocId=12264

Yeah, if it's anything like on a '84 300D (different car, I know, but still pretty similar I think) it is pretty straight forward.
However, might I suggest putting an extra backup underneath the engine, just in case? An extra jack stand perhaps, positioned right next to the jack?
I did it with the engine only on a jack as well, but thinking back on it: if my jack would have failed right as I had my hands in a wrong place, I might be writing this post with one hand. If the engine comes down at the wrong time, the results can be...well, pretty painful, I imagine.

On the passenger side you can't even reach the top nut with any sort of air tools. Its a hand tool only job. Unbolt one mount both top and bottom, jack up the engine by the oil pan using a thick piece of wood and replace the mount. Once first side is bolted back down repeat on the other side. Easy as pie.

I couldn't get the right side out with the left side bolted down, I had to pull both.

I know different animal but installing all bolts loosely until engine is back in place helps get the bolts lined up and installed on a 617. They can be tightened once all are in place.

Block you motor up or at least a big block between the frame and the motor.
I write with both hands because the 350 chebby I was changing mounts on
had a nice 2x4 between the motor and the frame with the jack I was using
popped a seal.

IT DOES HAPPEN !! Its noo biggie IF you are prepared for it. The jack was
about a year and a half old.

I got the bottom panels off to have a look and those top bolts look like they are going to be a total PITA to get loose. Times like these I wish I was a little heavier framed so I could just yank 'em free -- tight bolts make me quite nervous and I usually use air tools when I have access. I was going to do it tomorrow, but am planing to take the car up to Seattle to visit family this long weekend, so I may not touch it for fear of screwing up. (I could take the Saturn worst case, but I've gotten too darn spoiled with the comfort and quiet of the W124...)

We'll see how a fresh morning and some fresh coffee makes me feel about it. Should be a light day of thesis writing (I submit on Friday!), so I may just attempt it come daylight.

:/

has this car been in the salt? if not, you're going to be fine, do the left one first to get a feel, use a 1/2 inch drive with a long extension that gets you above the manifold and a universal joint if you need to, us breaker bar and have at it, they'll come loose. I can't remember MB used lock tight on those. PS, try to tighten them slightly further then loosen them, it's the best kept secret in mechanics

No, the car is rust free. It's just got very limited space around the bolts. I have a wide variety of hand tools and lots of extensions and breaker bars. The passenger side is what makes me nervous -- It looks like a box end wrench is about all that can get put on it.

Box wrench on the right sounds familar, or socket breaker bar only from below.

Happy Thursday Renaissanceman!

It is nice to be able to actually lend a hand. Normally, I am the one asking the questions. :-)

I have actually done this repair recently. Do not be afraid of this one. In fact, after having done the motor mounts on my 87 300TDT, I was contemplating doing the mounts in my wife's Honda Odyssey. (I decided against the Odyssey as there are 4-5 mounts and one is a royal PITA!)

The side without the turbo (right side?) is not difficult. I had more trouble installing the new motor mount than removing the collapsed one. It had totally failed. Had to raise the engine with the floorjack and plywood under the oil pan to install the new mount. Got it though.

Then I went to the mount on the turbo side (left side?). After scratching my head, shimmying under the car to see accessibility, peering over the top side, scratching my butt, I finally resolved to RTFFSM (Read the Factory Service Manual).

After reading it and doing a little more research, I found information to remove the entire mount from the side of the engine instead of just the actual liquid filled mount. After sliding under my car again, I decided to try it.

Holy cow did that make the job easier!!! Everything slid out without having any issue. Once I cleaned the mount and replaced the actual liquid filled mount, it almost put itself back on the car. :-)

I had several other pictures in post 9 here: http://www.peachparts.com/shopforum/diesel-discussion/365198-1987-300td-starter-help-needed.html

You will be amazed at how smooth the idle is after replacement!!! Well worth it.

Be safe and enjoy!

glenn

PS - Good Luck with your thesis!

Well, today was allocated to this job, but I got another round of thesis revisions jumped on me and just finished. The up side is that it's essentially done! I submit tomorrow -- 211 pages of very technically heavy writing, and many, many late nights over the last two months.

I'm heading to HF now to pick up a set of jack stands -- I was nervous with that heavy car up on ramps with no secondary support if I was going to be yanking and swearing at the bolts/mounts.

What are the torque specs on the top and bottom bolts? How about the mount to engine bolts?

Thanks!

just got in from changing them, not too bad. The top bolts came out like butter, the bottom ones were fairly rusty and needed convincing from a big breaker bar, but they came. I did not have to take the mount attachment off the engine, but I did have to reassemble with the old ones once to re-position the jack, but all in all pretty easy. Next time it will be a snap since I have done it!

The old ones did not look bad at all, (they look just like the other ones now that they have been free of load for a while) and were marked with a "B" in silver sharpie, leading me to believe that they have been replaced at some point. With 147k I would have expected to see a leaking mess like most folks here. I put in the new ones, and what a difference! Smooth and quiet, and when I shut the engine off, I thought something was wrong because it didn't give the entire body of the car a huge kick. I also checked the flex disks, and they both look great, and seem to have been replaced at some point.

Opulence.
:D:D:D:D

I also ghetto fixed my cracked flex pipe between the split manifolds. It holds at idle and has quieted the engine significantly. Pictures to come when I'm not exhausted.