Engine and transmission mounts

[Cees Klumper]

Jens (Supergrobi) in another post asked how to tell whether the engine mounts need replacement. These are located on either side of the engine, about halfway, below the aluminum "arms" that the engine sits on.
Apparently, worn engine mounts get depressed to the point of where the engine sits too low in the engine bay. In my case, I noticed it because the engine-to-exhaust downpipe dropped too low below the car, it could be very easily seen when looking low at the car from (either) side, causing the entire exhaust system to sit too low below the car. The rubber on our cars ages with time, not only use/mileage. If you have no clue how long it's been since the 2 engine (and the 1 transmission) mounts were replaced, definitely check their condition.
I replaced all three mounts in one evening, aided by a friend AND an extensive how-to write-up by Joe Alexander. The engine now sits higher (this also changes the geometry of the connection between the transmission and the driveshaft). There is less vibration in the driveline, less shaking of the tranmission lever inside the car when going over big bumps, and of course the satisfaction of knowing that yet another 'wear-and-tear' item has been refreshed. The mounts were not expensive.

Cees

white 1969 280 SL

[hands_aus]

Hey Cees,
My car CLUNKS every time I go over anything thicker than a pencil.
I was quoted AUD $500.26 for a pair of genuine MB engine mount kits, to be imported from Germany.
They also have an after market supplier who can provide them for AUD $38.30 each.
No there is no mistake, I typed it correctly.
So, I want to ask, do you think the MB mounts are gold plated?
I really only want black rubber ones.
Did you think about replacing your front subframe mounts too?
When you installed the rear transmission mount did you disconnect the gear lever linkage first and later adjust the linkage? I figure this would save any bushings being broken.

Bob(Brisbane,Australia)

[George Davis]

Bob, I paid about US$75-80 for 1 motor mount from a not particularly cheap source, a local independent MB shop.  Genuine MB part, no gold plate, though.  I suggest shopping around.

One note on the rear motor mount (under trans) is that there is also a rubber bellows that covers it.  It gets pretty oily down there so I guess it's to keep the rubber from rotting prematurely.

Just an opinion, but with a front end clunk I'd suspect softenend or worn-out subframe mounts.  If you decide to change them, you can replace the motor mounts and front brake flex lines at the same time as you'll be disconnecting them all anyway.  Figure about a day and a half if you DIY.

George Davis
'69 280 SL Euro manual

[Cees Klumper]

I dug up the invoice for the mounts, and the cost was as follows (August last year): engine mounts $35 each, transmission mount $50. I.e. a total of $120 for the lot. That's including our steep 19% sales tax, too! Something (logo/number) was ground off the rubber; this means that they are most likely original MB parts that the manufacturer (not MB) is selling as non-original to other resellers and therefore has to remove the MB trademark. Anyway they appear to be good quality. I don't think gold plating would improve significantly over plain rubber, but I could be wrong ;-)
I did not disconnect the gear linkage before changing the trans mount - it is an automatic and it did not seem necessary. No damage was done. Removing the heavy-gauge steel plate that the transmission mount sits on was the most tedious task - first I had to move the exhaust out of the way (and some of those exhaust bolts and nuts are a bit hard to get to) and then there are all those heavy bolts.
If your car clunks when going over anything thicker than a pencil, I would definitely check the condition of the mounts - and also whether the mounts and the metal surrounding them, are affixed properly. You may also want to check the condition of the rear axle central mount in the trunk (boot?) and on the bottom end of the same arm. And I am in fact considering replacing the subframe mounts as well. Most likely this is necessary also. Then I will build some kind of spreadsheet to keep track of all these improvements (so I know when it will be time to do them again)!

white 1969 280 SL