Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help




Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 06-11-2019, 11:23 PM
Registered User
 
Join Date: Dec 2005
Location: Carson City, NV
Posts: 3,780
W123 Engine Mounts Big Bolts Stop Short

I'm not feeling very smart right now. I swapped out the engine mounts in my 300D again, only this time, the big center bolts won't go in all the way. They start normally, but get very hard to turn with probably a half inch left before the washer makes contact with the bottom of the mount. The threads on the bolts look fine, and the threads in the arms look ok as nearly as I can see. I'm wondering if it's some sort of alignment issue getting the engine and the mounts lined up properly. What am I doing wrong here?
__________________
Anyone who thinks a 300D is fast drives too slow.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 359,xxx miles
08 Triumph Street Triple 26,xxx miles, lowered 10mm in front, Pirelli Angel GT tires, EBC HH brake pads, otherwise stock.
Reply With Quote
  #2  
Old 06-11-2019, 11:55 PM
Diseasel300's Avatar
Registered User
 
Join Date: May 2016
Location: Texas Hill Country
Posts: 4,657
Are you doing one arm at a time, or trying to do both at once? Doing one at a time is a wise idea as the other holds the engine more or less in alignment. I made the mistake of doing both at once the first time on my SDL and took me over an hour of prying, wiggling, and having a helper jiggle stuff to get the engine lined back up. Don't force it, you'll strip the threads on the bolt or the engine mount arm. Leaving the small bolts slightly loose can help get you a tiny bit of extra wiggle room to get things lined up.
__________________
'11 Honda Accord EX - "The Daily" 64K
'83 500SL Euro - "The Money Pit" 116K
'91 350SD - "The Diseasel Jr." 168K
'86 300SDL - "The Diseasel" 189K (Totaled 1/31/19)
The Diseasel Thread - Everything You Didn't Know You Wanted To Know
Reply With Quote
  #3  
Old 06-12-2019, 12:03 AM
dkr dkr is offline
Registered User
 
Join Date: Oct 2009
Posts: 549
It's probably an alignment issue. Use your jack to raise the engine and try to get a few threads on one and then work to the other side, release the jack and torque both sides.

Dkr.
Reply With Quote
  #4  
Old 06-12-2019, 12:50 AM
Diesel911's Avatar
Registered User
 
Join Date: Sep 2007
Location: Long Beach,CA
Posts: 28,294
Something similar happened to me when I cross threaded the bolt. But in my case it was only the first thread that got buggered.

What I had done was jack up one side of the Car and change out one Engine Mount and lower the Car and jack up the other side and changed the mount and that is where I got the alignment off and cross threaded.

So I jacked up both sides if the Car loosened the opposite side and used a tapered punch and a 2x4 lever to shift the engine around till the hole was line up. I don't remember the size of the tap but I was able to get a tape in there and chase the threads an I was able to screw the bolt in and tighten down both bolts.

When I changed the mounts again 5 years later I was careful to make sure the holes were lined up with a tapered punch and I did not tighten both bolts till both bolts were run all the way in OK. I also jacked up both sides of the vehicle so that the Engine would not slide over to one side.

In any event the Aluminum Arm comes off of the Engine. If you don't want to deal with the cross treading issue you could remove it and inspect it and see if it could be reworked by chasing the threads with a tap or a thread insert.

One person solved the issue by taking a drill bit and drilling all of the way through the Arm to the other side and putting a long bolt all the way through it and a self locking nut on the other end.
__________________
84 300D, 82 Volvo 244Gl Diesel
Reply With Quote
  #5  
Old 06-12-2019, 09:38 AM
Registered User
 
Join Date: Dec 2005
Location: Carson City, NV
Posts: 3,780
I tried to do both sides at once. The youtuber I watched did it that way and his was apparently easy. He must have gotten lucky. I'll start with dkr's suggestions. If that doesn't work, I'll make a trip to Harbor Freight and try the stuff Diesel911 suggested. Good call on drilling through and using a nut and bolt. I'm less worried about destroying the threads in the aluminum if things go pear shaped.
__________________
Anyone who thinks a 300D is fast drives too slow.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 359,xxx miles
08 Triumph Street Triple 26,xxx miles, lowered 10mm in front, Pirelli Angel GT tires, EBC HH brake pads, otherwise stock.
Reply With Quote
  #6  
Old 06-12-2019, 02:19 PM
Diesel911's Avatar
Registered User
 
Join Date: Sep 2007
Location: Long Beach,CA
Posts: 28,294
Quote:
Originally Posted by Skippy View Post
I tried to do both sides at once. The youtuber I watched did it that way and his was apparently easy. He must have gotten lucky. I'll start with dkr's suggestions. If that doesn't work, I'll make a trip to Harbor Freight and try the stuff Diesel911 suggested. Good call on drilling through and using a nut and bolt. I'm less worried about destroying the threads in the aluminum if things go pear shaped.
Anther forum Member thought that up.

Stuff that people post when nothing goes wrong give the allusion that everything will be the same when you do the job. In fact even if you have done the job several times before some un-know problem will show up the next time you do the same thing.
__________________
84 300D, 82 Volvo 244Gl Diesel
Reply With Quote
  #7  
Old 06-16-2019, 08:50 PM
Registered User
 
Join Date: Dec 2005
Location: Carson City, NV
Posts: 3,780
Fixed

I loosened up all the little bolts, used a big Phillips screwdriver to get the holes lined up, and tried again. The bolts still didn't go all the way in. I went to NAPA and got some new bolts, a 10x1.5 tap, and a tap handle. I found the tap didn't reach easily, so I tried the new bolts anyway. They're also 10 mm shorter, since NAPA was out of 10x1.5x40 bolts. The new ones went right in all the way. After a short test drive, things seem pretty good.
__________________
Anyone who thinks a 300D is fast drives too slow.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 359,xxx miles
08 Triumph Street Triple 26,xxx miles, lowered 10mm in front, Pirelli Angel GT tires, EBC HH brake pads, otherwise stock.
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 10:31 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page