Mercedes-Benz Forum banner

21 - 40 of 48 Posts

·
Registered
1982 300SD
Joined
·
30 Posts
Alright, I've tried to align the hub and axle as closely as possible. I've given the slide hammer a couple of serious smacks and nada. I am a little reluctant to beat on it too much for fear of damaging something.

2638549
 

·
Registered
1982 300SD
Joined
·
30 Posts
I'm awaiting the delivery of a 14mm allen for the diff's drain plug. But I'm about to just pop the diff cover before draining it which should allow me to pull the 'C' clips on the diff side of each CV joint. But even with those clips out, I'm not sure that it advances my goal of dismantling the whole rear axle.
 

·
Premium Member
2015 ML250 Bluetec and 1987 560SL
Joined
·
3,603 Posts
Right. That bolt, along with the washer, are what hold the axle end into the wheel hub. With the bolt and washer removed, it should slide right out. Lining things up will make it move more easily. You can also wiggle the axle up and down at the wheel end to get it to unstick.

In my case, the axle wouldn't quite slide enough to clear the inner end of the wheel hub. I was able to get it out with enough fiddling, but I couldn't get it back in until I unbolted the inner trailing arm mounting bolt and swiveled the arm a little around the outer bolt to provide the extra clearance.
 

·
Premium Member
1986 560SL with M120 V12 Engine, 1988 560SL Stock
Joined
·
10,432 Posts
Alright, I've tried to align the hub and axle as closely as possible. I've given the slide hammer a couple of serious smacks and nada. I am a little reluctant to beat on it too much for fear of damaging something.

View attachment 2638549
You shouldn't be trying to be removing the hub from the axle that way. You need to press the axle out of the hub. Drive the axle into the hub with a brass drift, after you take the center bolt out of course. The axle should compress enough to clear the splines.
 

·
Premium Member
2015 ML250 Bluetec and 1987 560SL
Joined
·
3,603 Posts
@roncallo is right. Th axle slides out of the hub, with the hub still securely mounted to the trailing arm. Don't try to pull the hub out of the trailing arm with the slide hammer.
 

·
Registered
1982 300SD
Joined
·
30 Posts
Jay, Thank you for your time and help on this. I sincerely appreciate the weekend support.

I think I'm missing something fundamental. I may also be confusing some of our terms.

In your experience, when you've had a rear axle (cv joint) splined with the wheel hub (the part with 5 bolt holes which the tire mates with), did you separate the two with just using a mallet on the back side of the rotor's backing plate rather than my sliding-hammer attached to the front of the wheel hub?

This has been a California car for its entire life. There's no rust or corrosion anywhere so I'd be a little surprised if the axle and hub are rusted together. But anything is possible.

-j
 

·
Premium Member
2015 ML250 Bluetec and 1987 560SL
Joined
·
3,603 Posts
You're trying to pull the wheel hub off of the axle. That's backwards: you need to pull the axle out of the wheel hub, inboard toward the centerline of the car. (Or push it from the outboard side of the wheel.)

Forget what you know about American cars. Germans do things differently. (See my signature.)
 

·
Registered
1982 300SD
Joined
·
30 Posts
You're correct - I've been trying to pull the hub off, rather than gently tap the cv joint's spline inward, toward the differential.

I've yet to perform this step, but it now makes sense to me. I'll assume that there's enough space in the joints that it'll collapse and clear the back of the hub. I'll want to tie up (support) the wheel side of the cv joint before tapping the spline, to avoid it dropping to the ground.

Thanks again for your patience with the backward questions. I think I've got it now.

Enjoy your weekend!
Jeff
 

·
Registered
1982 300SD
Joined
·
30 Posts
Jay, the spline is out. The birds are chirping once again and the sky has cleared.

I have the car's full weight on the rear tires and, for this discussion, the top two nuts, rubber bushing and large flat washer, for the driver's side shock are removed and I'm about to liftd the car allowing the entire shock to be removed.

My question: I've read conflicting reports regarding using a spring compression tool, or not. At this point, can I simply jack up the car and allow the a-arm to drop sufficiently to allow the coil to be removed under no spring tension?

Or do you recommend a compressor? I have the plate type I used on the front wheels, but if I can avoid using it... my feelings would remain intact.

Jeff
 

·
Registered
1982 300SD
Joined
·
30 Posts
Hey Ron,
Thanks for your help/post. My mental model was definitely backwards.
My earlier W126 challenges taught me that when things don't make sense, initially, there are usually engineering details that are quite sound. Just gotta love German engineering!
 

·
Premium Member
2015 ML250 Bluetec and 1987 560SL
Joined
·
3,603 Posts
My question: I've read conflicting reports regarding using a spring compression tool, or not. At this point, can I simply jack up the car and allow the a-arm to drop sufficiently to allow the coil to be removed under no spring tension?
If' you've got the plate compressor, use it. The trailing arm will come down against a stop, and that will not let the spring tension completely release. OTOH, having it down against the stop means you won't have to compress the spring as much to get it out as you would if the arm was in the normal position. Make sure to jack the car up so the arm does go down against the stop.
 

·
Registered
1982 300SD
Joined
·
30 Posts
Thanks Jay. I've been savoring (sadistically perhaps) the rear half of this suspension redo. The shock and spring are now out (driver's side only). I'm wrestling with dropping the entire control arm to replace the bushings. I figure, in for a penny... So I'm poking about looking for best practices for the two bolts holding the arm in place. Any thoughts would be graciously accepted. Regardless - thanks for the input to date. It may take me another week, but here in Silicon Valley we're all still locked down, so I'm in no super hurry. Thanks again! Jeff
 

·
Premium Member
2015 ML250 Bluetec and 1987 560SL
Joined
·
3,603 Posts
Sorry I didn't reply sooner...been up to my ears in other stuff.

The only thing to remember (aside from the fact that the trailing arm mounting bolts are 24mm on both the bolt and the nut) is that the tightening torque is somewhere around 100 foot-pounds. (RTFM for the exact value.) I wasn't able to reach that torque myself, so I pulled on the wrench as hard as I could and called it good.

Oh, and Astroglide works very well to get the bushings into the trailing arm holes.
 

·
Registered
1982 300SD
Joined
·
30 Posts
Hey Jay,

No problem, at all. These are weird times and wrenching on an old Mercedes, at least for me right now, is both a burden and distraction. I too have a few things other than a w126 up on jacks to worry about.

Thanks for the trailing arm bolt insights. I went with the 15/16ths box/open (rather than the 24mm approach) and came to the conclusion that there is no way I would be able to get to the outer bolts on the trailing arms w/out dropping the entire sub-frame down, if not completely, then partially.

I've been reading thread after thread on multiple sites attempting to synthesize a mental image, or perhaps a visual road map, on how to best proceed.

My other recent epiphany is that the 2x bolts at the top of the diff cannot be reached w/out dropping it down. So w/out the cover removal, there's no pulling the cv-joints. Argh...

So I'm inching my way toward dropping, perhaps not completely, the subframe. Today's task - exhaust bolts, then rear drive shaft (maybe not completely) flex-disc, to disconnect it from the diff.

Then.... off to Harbor Freight to p/u a transmission jack to support the diff. Oh yea, both rear springs are now out. Passenger side, while compressing it, slipped out of the bottom of the cup, obscuring the 19mm spring compressor bolt. Had to use an open- end 19mm wrench to finish compressing the spring. Placement of the compressor plates at both top and bottom is critical to making the compression and spring removal possible. But with practice....

With a job like this one, it's rather easy to become overwhelmed. Fortunately, I'm not in any serious hurry. I get frustrated and take a brake to ruminate over the issue until I've charted a path forward.

Do allow me to thank BenzWorld and its participants. The various threads, though not all applicable, have been very valuable fodder. And thank you for your help and engagement.

Most sincerely -Jeff
 

·
Premium Member
2015 ML250 Bluetec and 1987 560SL
Joined
·
3,603 Posts
Thanks for the trailing arm bolt insights. I went with the 15/16ths box/open (rather than the 24mm approach) and came to the conclusion that there is no way I would be able to get to the outer bolts on the trailing arms w/out dropping the entire sub-frame down, if not completely, then partially.
This is correct. You must drop the subframe at least a bit to get to the outer trailing arm mounting bolts. So yeah, bite the bullet and just do it.
 

·
Registered
1982 300SD
Joined
·
30 Posts
Today's task is the driveshaft. Question: is it sufficient to simply disconnect the diff/driveshaft joint, or should I mark the two connections points, between the driveshaft and center bearing, and extract that section? Again, with the goal to drop the subframe?
 

·
Premium Member
2015 ML250 Bluetec and 1987 560SL
Joined
·
3,603 Posts
I simply disconnected the differential from the driveshaft and pushed the driveshaft forward, which was enough to get it to clear. Others have had to remove the driveshaft. There is a nut that locks the driveshaft lengthwise, at the center bearing; I suspect mine was simply not tightened for some reason.

You don't need to mark the differential/driveshaft joint, but if you do split the driveshaft, make sure to mark both halves so you put it together the same way it came apart.
 

·
Registered
1979 450SL UK spec
Joined
·
1,497 Posts
548 pics here in this gallery showing me removing the rear suspension and sub-frame. First trying with the prop shaft in place then after working out that I had to remove it.

Start with the last pic (548) in the gallery and then work towards the front (you can move forwards or backwards through the pics by clicking on the far left or far right of the pic).


There is a second set of pics of me stripping the suspension after all the boadywork pics at about pic 353 and then the rebuild starts at about 188.
 

·
Registered
1982 300SD
Joined
·
30 Posts
Hey Jim, beautiful! Thanks...!

I'll step through the photos in detail shortly. I've just hit a snag where they might help.

Today's goal (was): remove diff and cvjoints :

- Splines are unbolted and pushed inward, toward diff,
- Driveshaft unbolted and pushed forward,
- 4x vertical bolts holding the rear diff support bushing/housing removed,
- 4x monster 19mm (3/4" alt) top nuts holding the diff to the subframe are out (serious argh!).

With that said (done) however, the diff doesn't seem to want to dis-associate with the subframe.

Question: am I missing a rogue nut/bolt (not according to the service manual)? Or perhaps, after 37 years of service, could it just need some gentle (or not-so) persuasion? It's only 12:40pm pst and I'm about done.... for now.

Time for food, review of your W126 mega-photo assortment and general retreat & regroup.

Thanks guys, you're my current mech-gods!
 
21 - 40 of 48 Posts
Top