Remove rear trailing arm...almost there - PeachParts Mercedes-Benz Forum

Rudebutler · #1 10-12-2013, 10:16 AM

I had the shock absorber go through the passenger rear trailing arm on my 83 300D. The threads I read made it sound like I did not need to remove the entire rear end to take out the trailing arm. I removed the carriage bolt and was able to remove the bolt that attaches the outside of the arm to the subframe. But I cannot slide the bolt out on the inner mount- it hits the transmission flex plate.

Is there a way to lower the subframe more to make clearance for the bolt? Do I need to remove the flex plate (I just had it installed recently)? Is there another option here?

Diesel911 · #2 10-12-2013, 12:33 PM

Quote:

Originally Posted by Rudebutler

I had the shock absorber go through the passenger rear trailing arm on my 83 300D. The threads I read made it sound like I did not need to remove the entire rear end to take out the trailing arm. I removed the carriage bolt and was able to remove the bolt that attaches the outside of the arm to the subframe. But I cannot slide the bolt out on the inner mount- it hits the transmission flex plate.

Is there a way to lower the subframe more to make clearance for the bolt? Do I need to remove the flex plate (I just had it installed recently)? Is there another option here?

I am not sure which side you are working on but am guessing it may be the Right rear.
When I removed the Left Trailing Arm I removed the Subframe Bolt on that side and lowered the Subframe a bit.
The bugger with that is that that is also the Jacking point under the Car.

In My case I happened to have a nice hardened Steel Rod in that I suck into the normal Jacking Hole. I jacked up the Body using the Subframe Bolt area as the Jacking point and put a Jack Stand under the Rod and I lowered the Jack and let the Rod rest on the Jack Stand and then was able to remove the Jack from under the Car and get at the Front Subframe Bolt.
You could do the same with the regular Car Jack but it would not be safe.

I don't know for sure if that will give enough clearance on the right side.

Rudebutler · #3 10-12-2013, 01:03 PM

Thanks Diesel911

I am working on the left rear. I have unscrewed the subframe bolt at the jack point. The problem isn't hoisting the car, I have that done according to another thread.

I attached a photo. It shows the inside mount of the trailing arm to the subframe. I circled the head of the bolt as it hits the flex disc. Is there another bolt I can unscrew to lower the subframe another inch or 2?

Stretch · #4 10-12-2013, 03:41 PM

I think you're gonna be a bit stuck. I've only ever taken off the trailing arms with the whole sub frame removed. You could lower the differential by undoing the four bolts that hold it to the sub frame and the rear differential mount. Or remove the propshaft and the flex disc...

...of the those two options I'd do the propshaft and the flex discs. Those bolts on top of the differential are absolute %^%&%&8ing %%^%ds...

...and you'll have the added problem of holding up the sub frame if you do the diff drop.

Diesel911 · #5 10-12-2013, 05:06 PM

Quote:

Originally Posted by Rudebutler

Thanks Diesel911

I am working on the left rear. I have unscrewed the subframe bolt at the jack point. The problem isn't hoisting the car, I have that done according to another thread.

I attached a photo. It shows the inside mount of the trailing arm to the subframe. I circled the head of the bolt as it hits the flex disc. Is there another bolt I can unscrew to lower the subframe another inch or 2?

I guess My Memory is not correct.

It could be that the Nut on mine was on the side facing the Flex Disc.

I am sure I did not remove the Flex Disk as I changed the Left Trailing Arm sometime in 2008 due to Me cracking it in an Accident.
I did not touch the Flex discs till about a year ago.

Is it possible to put a Jack under the Rear Differential and remove the Differential Support and move the differential up so the Blot Will Clear the Flex disc?
If not you need to detach the Flex Disc.
If you do that I think you need to remove the Bolts from the Drive Shaft Mount and loosen the Retaining Collar up front so that the Drive Shaft can be collapsed forward.
I spent a good deal of time trying to pry off the old Flex Discs.

Once it is pulled back inspect the centering Bushing and put some grease inside of it if the Grease is dried up.

gear-head · #6 10-12-2013, 06:34 PM

Quote:

Originally Posted by Stretch

I think you're gonna be a bit stuck. I've only ever taken off the trailing arms with the whole sub frame removed. You could lower the differential by undoing the four bolts that hold it to the sub frame and the rear differential mount. Or remove the propshaft and the flex disc...

...of the those two options I'd do the propshaft and the flex discs. Those bolts on top of the differential are absolute %^%&%&8ing %%^%ds...

...and you'll have the added problem of holding up the sub frame if you do the diff drop.

Stretch knows what he's talkin' about here! Any other approach to this is just a huge waste of time and effort!! So don't keep =>

Simply put, dropping the subframe to deal with this issue won't "get you there", the diff is mounted to the subframe soooo.....remove the flex disc & drop the driveshaft and be done with it already!

Diesel911 · #7 10-12-2013, 06:54 PM

Quote:

Originally Posted by gear-head

Stretch knows what he's talkin' about here! Any other approach to this is just a huge waste of time and effort!! So don't keep =>

Simply put, dropping the subframe to deal with this issue won't "get you there", the diff is mounted to the subframe soooo.....remove the flex disc & drop the driveshaft and be done with it already!

???How, did I manage to change the left Trailing Arm without removing the whole Subframe. The only special problem I can remember having is that I had to heat one of the Trailing Arm Nuts to get it to turn; it did not want to budge.
I was so new to this Forum that I used a Spring Compressor on the Rear Spring because I did not know any better.

My Wife just came back with the Car. I went out and took a look. The inner Left Trailing Arm Bolt on mine is on the Flex Disc side and there is has about 2-1/2+" inches before it reaches the Flex Disc. Apparently mine has more room that the Original Posters does.

Is it possible that the Differential cases have different lengths and that puts the Flex Disc closer to the Bolt Head?

Graham · #8 10-12-2013, 08:08 PM

Before I gave up on changing my trailing arms, I did a lot of reading here. I recalled someone having same problem and just found the post:

Quote:

Finally got around to actually replacing this arm..

Still in progress, however cant remove the inner bolt closest to the drive shaft. The flex disc is in the way :/

I'd rather not remove the flex disc, trying to figure out a way around that...

UPDATE: annnd I didn't need to remove it at all.

I had to cut the parking brake cable for this side. No big deal, new one is only $30. I don't think I've used the parking brake ever. I've got all the hardware stashed away, maybe next time I have the car up in the shop, I'll have them repair all of that.

Full post here: http://www.peachparts.com/shopforum/2920882-post17.html

I don't think Jamesdean explained how he solved problem, but you might ask him.

ImBroke · #9 10-12-2013, 09:47 PM

I'm in the midst of this now, and I dropped the whole rear diff. Can't finish it til I get back from travel, so I'm looking forward to getting it done and over with.

vstech · #10 10-12-2013, 10:32 PM

keep in mind, the 126 has a few more inches of width between the diff ,and the trailing arms...
also, there are different size flex discs. I have a few subframes sitting in my garage, and a stack of trailing arms, I could look over the issue tomorrow, in the garage and take pics if needed...
also, keep in mind, the subframe is two pieces, and disconnecting it, may cause one part to move enough for the arm to clear?

Rudebutler · #11 10-13-2013, 04:21 PM

Thanks Stretch! Not the answer I wanted but reconfirms what I was thinking.

So, it's off with the flexdisc.

I'll post pics of the arm once its off. Not sure it can be salvaged

kerry · #12 10-13-2013, 04:37 PM

Cut the bolt with a sawzall?

Rudebutler · #13 10-13-2013, 07:38 PM

Certainly that solves the "getting it off" problem. Good idea, I had already considered it. But I imagine I'll want a trailing arm back on the car at some point

There's no way to get the bolt on with the disc there. And you can't put the bolt in the other side. There's not enough clearance with the bend in the arm. Alas, there's plenty of room on the driver's side trailing arm

Graham · #14 10-13-2013, 08:51 PM

I wondered if you could have got the bolt out if you had removed just one bolt on the flex disk?

Surprised others who did these 1 at a time without dropping subframe didn't have same problem.

Rudebutler · #15 10-17-2013, 08:08 PM

I finally got the arm off- thank you for all the help

Here are pics of the arm. Everything is solid and firm even though corroded. Does it look salvageable? I've seen repair threads using large washers.

I don't weld so any advice is greatly appreciated