motor mounts and shakes - PeachParts Mercedes-Benz Forum

brownrice78 · #1 03-02-2016, 07:31 PM

Just replaced my motor mounts. Just sharing my experience and also need some help.

As far as the mounts. Wow, huge difference. I had one mount that was completely collapsed. Some tips for the next guy. 8mm underneath be careful not to strip the bolt. Hit the bit with a hammer to seat it well and use a breaker bar to get it moving. I took the bolts out and then slightly threaded one in while working on the other mount. I didn't have issues lining up the 8mm screws I think because of that. Both inner bolts I got out from the bottom. Can't imagine how u can reach them from up top. I removed the air filter housing for space.

Now for the question. The mounts took out the violent shakes but the car still has a rhythmic shake going on. Worse at hot engine. Should I replace the rack damper screw? Also, the car shakes a bit when you turn it off , does that indicate the engine shocks are bad? I couldn't quite tell if the engine shocks were good. I had to pull them down to get the bottom bolt on. Does that indicate anything?

Thanks guys.

leathermang · #2 03-02-2016, 07:40 PM

Does your vehicle require a home made tool to check to see if the engine is positioned correctly with respect to the motor mounts ? IE, not under stress one direction or another when installed ?

brownrice78 · #3 03-02-2016, 07:55 PM

I'm not sure how I would check to know if the engine is positioned correctly? The car always had the hot shakes so not a new issue.

Mxfrank · #4 03-02-2016, 08:03 PM

Which car? Rack damper screw applies to turbo only.

Yes, the shocks need to be replaced from time to time and can explain the shaking.

brownrice78 · #5 03-02-2016, 08:34 PM

83 300d turbo

Clemson88 · #6 03-02-2016, 08:52 PM

Quote:

Originally Posted by leathermang

Does your vehicle require a home made tool to check to see if the engine is positioned correctly with respect to the motor mounts ? IE, not under stress one direction or another when installed ?

What about this homemade tool to check engine to mount position?

Stretch · #7 03-02-2016, 09:05 PM

When you replaced the two engine mounts at the front did you replace the transmission mount as well?

leathermang · #8 03-02-2016, 09:19 PM

There are threads and a schematic in the archives.... not sure if all vehicles require that positioning device when replacing the mounts... but worth checking out...

Give the vin and exact type of car you have... 123.??? for example .. or 115.???
Do you have a FSM for your engine ?

'' Engine suspension'' is at the first of the NA FSM... but near the back of the turbo FSM.

Diesel911 · #9 03-03-2016, 12:00 AM

General causes of shaking at idle speeds.

Motor and Transmission Mounts no good

Engine needs valve adjustment.

Air leaks in the fuel inlet lines.

Worn out Injector Nozzles and or Injectors that do not have the correct or balanced Injectors. Also the Stock Injector Nozzles have 2 tiny drilled passages in the little pintel that can ge entirly plugged solid with carbon.

New Gold colored Rack Dampner/Governor Idle Screw.

The idle speed needs to be within the range listed on the emission sticker.

If all of the above was done but it still shakes a compression test may show uneven compression.

brownrice78 · #10 03-03-2016, 10:59 AM

Good ideas. I didn't change out the transmission mount. Hard job?
The rack damper screw hasn't been changed. That's another good idea. Who sells them btw?

I adjusted the valves recently. I haven't done anything with the injectors

leathermang · #11 03-03-2016, 11:03 AM

Are you going to post your exact vin info ? re post number 8?
the chart is too big to try to type out...
may not apply to your car at all...

mannys9130 · #12 03-03-2016, 02:14 PM

The transmission mount isn't a hard job at all. If you did the motor mounts, you can definitely do the trans mount no problem.

I'm sure PeachParts sells an updated rack damper.

How many miles would you say the injectors have on them? Have you done a diesel purge recently?

brownrice78 · #13 03-03-2016, 03:57 PM

Diesel purge I have done. I've never touched the injectors

Junkman · #14 03-03-2016, 04:36 PM

Quote:

Originally Posted by leathermang

Are you going to post your exact vin info ? re post number 8?
the chart is too big to try to type out...
may not apply to your car at all...

I haven't noticed this in the 126 FSM on CD. Does it apply to 84 or 85SDs? Can you link the chart? I'm willing to host it on dropbox. Send a PM if that is feasible. I already have the digital FSM there but don't post the link because of the copyright.

cho · #15 03-04-2016, 10:48 AM

Quote:

Originally Posted by brownrice78

Worse at hot engine.

if significantly worse while hot (i.e after 20-30 miles highway ride)..I would go for delivery valves.

cheers

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