Rant: Aluminum Engine Mount Arms
 

What dim-witted, kraut for brains decided to make the threads of a difficult to align hole out of ALUMINUM?!?! :mad: :rolleyes: My original arm had such messed up threads that the bolt would not tighten down so I replaced it. I carefully aligned the hole by prying on the mount, put the bolt in a turn or so by hand, then started with the ratchet but it didn't feel right so I stopped after a turn and pulled it out. Sure enough the threads were starting to get buggered. I tried aligning the hole again, but it still did not feel like the bolt was going in as easily as it should have. I tried again several times with the same result so I just finished screwing in the bolt. I think the one turn I did before pulling it the first time was all it took to $crew the threads on the new one up. :mad:

I plan to make a steel insert to replace the aluminum threads next time I do this job.

I think that the Haynes Manual is responsible for a lot of those stripped threads. The torque spec it lists is way higher than the MB service manual spec.

I know exactly what you are talking about. Is there enough space to use a helicoil? I have used helicoils in transmission cases but not in MB engine mount arms.

I never had a problem with lining them up.....only problem I had was that my left one was stripped and missing the bolt when I got the car (80), I tried installing the correct bolt (when I discovered it was stripped). I drilled it out to the next handy size for what I had around here, and retapped it to fit some sort of (suspension bolt I think) from a Toyota 4x4 I had scrapped out. The fix outlasted the car, that's all I could ask of it,lol.

I agree its a very dumb idea, why not just make an entirely new mount out of some angle iron steel?

I've never had problems.... Stupid Haynes, they should be sued (or atleast print a new edition).

I had to replace one of those arms recently. It maded my look forword to the front sunroof seal.

RANT ON!
is English grammar no longer needed?
anybody wanna try to figure out the intended message in this sentence? is the arm in the planning stages of change? has it already been accomplished? I am not even going to touch the followup statement.
whoo-boy!
OK, RANT OFF! sorry.
the use of forged aluminum is a great weight savings. look at the amount of weight it supports, if steel was used, it would need to be tubular and connect all the way around to be as strong as the aluminum arm is. that car is heavy enough! perhaps MB didn't want to put steel threads in there for fear of vibration damage or something. who knows? I like the mount. I do wonder if the threads were tapped in there, or if a blank hole was set and the original motor mount bolts just threaded their own in there...

Sorry. (Remembers not to post before having caffine) Grammer corrected.

me likeey to poke fun at ums of'imes...

I have the same issue with my driver's side arm. I couldn't align the arm to the mount hole and basically what it felt like a cross threaded it when I tighten it down. Now 20,000 miles later I am beginning to hear a clunk, clunk, clunk every time I shut down or stop at a light. The sound is coming from that mount.

I am not looking forward to replacing this arm!

roflmao!

But not the spelling...ROFLMAO!

GRAMMER??
If I'd have corrected her she'd have slapped me silly.

This has quickly become the most confusing thread I have ever read