What's this part called?

[bpossel]

What is this part called?  It is part of the rear axle.  There are, what looks like, 2 rubber bushings, one on each end.  My bushings have fallen apart and only a small bit remains.

What's this part called and has anyone ever replaced these bushings?  

Thanks!
Bob

Download Attachment: whatsthis.jpg
62.78 KB

bpossel
Memphis, TN.
1971 280SL
1997 E320

[Vince Canepa]

That is called the hanger mount.  To change it the right side axle must be removed in order to get the hanger mount out.  An alternative suggested by Arthur Dalton is to remove the input flange on the differential and pull off the seal holder housing at the front of the differential.  I did the job last summer, but I pulled my entire rear axle assembly.  I had some discussions with Arthur that can be seen at http://index.php?topic=3879  You might also search on hanger mount.  I found the handling of the car vague and uncertain with a bad mount.

Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex

[bpossel]

Hi Vince,

Thanks for the info and additional direction for this project!
Lots of good info on the site about this.

I will try and approach this replacement of the flex tube rubber bushing without dropping the entire rear suspension.  I will use the newer designed 1-piece vs 2 piece and also replace the pinion seal.

JA, or AD, any additional advice?
Thanks!
Bob

bpossel
Memphis, TN.
1971 280SL
1997 E320

[Vince Canepa]

Bob - I am sure that Joe or Arthur will advise you to be very careful about marking the position of the nut holding the input flange onto the pinion shaft.  The reason is to preserve the preload on the pinion bearings.  The preload is established by crushing a sleeve on the pinion shaft when initially setting up the differential.  If you return the nut to it's previous position, the theory is that the preload will remain very close to the same.  Arthur has a second check that measures the overall torque required to turn the complete final drive.

I had trouble finding the single piece bushing.  I think Ray Paul may be the only source.

Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex

[bpossel]

Hi Vince,

Thanks again!

Any other add'l parts needed, or just the new "single piece" bushing?

Regards,
Bob

bpossel
Memphis, TN.
1971 280SL
1997 E320

[Vince Canepa]

I would look at the rubber donuts at both ends of the cross strut and the mount at the top of the hanger braket (accessed from the trunk).  Keep in mind that all this stuff locates the rear axle.  It is very important that it be in top shape for the car to feel right.

Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex

[bpossel]

If all that I need to replace is the rubber bushing (part number 221-111 on the attached pic)can I just loosen the clinch bolts and remove the front bolt and lock washer and slide the bushing out and replace it?  Obviously, need to have the axles supported and at 90 degrees to the hanger?

What am I missing?

I ordered the new single piece bushing from Ray Paul today.  Nice guy!

Thanks!
Bob

Download Attachment: rearax.jpg
71.45 KB

bpossel
Memphis, TN.
1971 280SL
1997 E320

[A Dalton]

<<What am I missing?>>

 You can not get the part past the differential front cover.

[Vince Canepa]

Bob - As Arthur points out, the forward end of the bushing fits into the "eye" on the differential front cover.  That is what the pinch bolt is clamping.  You can't slide the bushing aft more that a few millimeters even if you remove the shim between the aft end of the bushing and the right axle half.

Also, after installing the bushing, but before clamping everything down, the longitudinal position of the hanger bracket/mount must be set.  I'm not quite sure how you do that in the car - perhaps Arthur can help or posted on this earlier.  The measurement is from the face of the input flange back to the forward edge of the hanger bracket - where it fits into the top mount.  Maybe you can drop the center of the axle assembly down far enough to get the measurement.  I think the dimension is 168 mm.

And for more fun, the hanger bracket must be perpendicular to the axle tube.  The reason is to have the rubber in the bushing "without tension", as the Germans would say, with the car at rest on the ground.

This may all sound like overkill, but I cannot emphasize enough how important this mount assembly is to the feel of the car on the road.

Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex

[Benz Dr.]

I had to do one on a 6.3 a few years ago. For those who don't know, 6.3's have air suspension and there's a lot more work to R&R this axel. I did this job without removing the axel and it works fine.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061

[bpossel]

Hi Dan,

Hope you are doing ok!

Thanks for the post.  I was thinking that this job (replacing the support tube rubber mount) would not be possible w/o dropping the entire rear end (ensuring proper alignment, etc...)...  Your post has given me more encouragement to proceed.

As long as I ensure that both axles are perpendicular to the axle carrier tube/bracket, it should work, right?  Will I need to disconnect the trunk mount?  I am hopeing to leave that one alone since I already replaced it a year ago..

Any other suggestions or comments to help make this replacement go smooth?

Thanks Dan!  Take care..
Bob

bpossel
Memphis, TN.
1971 280SL
1997 E320

[Benz Dr.]

I have this part available for 57 bucks and usually keep one around. It should be noted that Ray ( who I know and like ) actually works for Bud's Benz although he still works out of his home office. It's simply dropped shipped from GA.

I thought about this repair today while sliding through the CT machine and maybe the air suspension allows for the axel tubes to move upwards more than a standard rear axel. I remember having to tweak it into place, and it just went in.

I use an ordinary level and a framing square to set the axel up. I'm sure it's within a degree or two of being 90 degrees. You might have to drop the whole axel in the end. I've replaced quite a few of these mounts but the axel was already out of the car.
 Don't take the axel apart, they're really hard to make right again. The pinion nut can be removed and then put back on without problems ( usually ) as long as nothing else was disturbed. I've done it many times and it always seems to work out.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061

[bpossel]

Hi Dan,

Hope that the doctors are treating the doctor with care...

Thanks for the add'l info.  Using the level is a great idea!

Best of health,
Bob

bpossel
Memphis, TN.
1971 280SL
1997 E320

[Vince Canepa]

Bob - Dan seems to be confirming what I thought.  It isn't all that easy to do one of these in the car.  It took me less than an hour to drop the whole assembly out.  Then all you have to do is drift the pivot pin that runs through the mount aft far enough to remove the hanger mount.  Change the bushing, slip the hanger bracket/mount assembly back in, set the fore/aft dimension and the 90 degree angle, tighten all the pinch bolts and put the assembly back in.  The toughest part is compressing the compensating spring.  I made a compressor out of some 1/4" x 1 1/2" flat bar and some threaded rod.  I still haven't figured out how you set the fore/aft dimension in the car, although I am certain I have read how to do it somewhere.  Sometimes trying to avoid what looks like a big task actually makes for a worse task.

Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex

[Benz Dr.]

Sounds good. Every job has a fewtricks that can save you a lot of time or work. Sometimes you can't avoid a really tedious job.
It can take 3 or 4 hours to change a front right motor mount on a 190SL. Remove the plenum chamber, remove the front carb, remove the generator, remove the motor mount.
 Why? Because you can't get the scew out of the motor mount with the generator right above it. Can't get at the generator with the carb in thereHave to remove the plenum to remove the carb.
You can pull the rad but first you have to remove the hood and you still need to remove the generator.

See why I say they're hard cars to work on?

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061