Rear wheel bearing and CV axle removal

[ewenjo]

Hi

As I wrote before I am going to replace the rear wheel bearings on my 1982 380SL.

I read most of the comments including the Morrison step by step procedure.

There is only one item I am not too clear on and need some advice.
It's the removal of the axle from the hub.

The Morrison procedure as well as the MB CD says to remove the bolt and spacer.
Then use the removal tool or as Morrison says, use a bronze drift pin.
Okay but... I assume the CV axle has a universal joint that will allow the shaft to push out.
Is that correct?
Or do I have to disconnect the shaft before pushing it out of the hub? Is there enough slack?

Thanks for any comments.

[Deltacom]

It depends on the type of rear suspension you have on your 82 380SL.
See This Thread and let us know your type or pics of your suspension as there are different procedures.

[daidnik]

Getting the CV half shaft out isn't too bad. Have to remove the differential cover to pull the retaining clip from inside to get the that out if you want that, but if you're only going to do the wheel bearing, you can just wire hang it with the wheel side disconnected.

I think getting the bearing races out of the trailing arm will require removing the trailing arm. If it's the drivers side, that'll also require disconnecting the drive shaft from the differential to get the inner bolt out. You will need the special 4-prong tool for the nut holding the wheel bearing assy in the trailing arm and you'll need to setup a bolt/allthread/washer setup thru the hub to keep that tool from slipping off the nut. You also have to keep the hub from turning. You could use the brakes with a helper for removal on the car, but putting it back together with a new crush sleeve will be a lot tougher especially if you are going to set the indicate the free-play to 0.002"=0.05mm as you need good control of the tools in torquing those final fractional turns on the nut. I did this off the car.

I made a counter-hold out of an old brake disk by drilling a couple of holes thru the disk and mounting a 4 foot piece of steel 1x1x1/8 square tubing to the disk. Even with two people, it's hard too get that crush sleeve started in compression. After that it's not too bad as long as you don't go too far or then you have to start all over with another new crush sleeve, so that part is tricky and you must use a dial gauge to do it correctly.

Pulling the hub assy out of the trailing arm with a slide hammer can be a pain when the trailing arm is off the car as the arm is a weird shape without any good spot to anchor against. Maybe a chain to an anvil might be good. On mine, I had someone hold it against some wood on the ground and it took me many vigorous whacks with a 5 lb slide hammer to get that thing out. I would think that R&R of the bearing races will require removing the trailing arm from the car. Drifting the bearings out with a brass drift can be hard without a really nice solid anvil or steel table on a concrete floor. You really need that kind of solid impulse in the applied force to get the bearing races removed and solidly seated in installation.

Geez, I forgot to say that you also need the special spring compressor to get the spring compressed and get it out thru the cutout in the wheel well. That job is a pain! I only did it a couple of months ago and I've already forgotten how hard it was. Maybe some do it all with the trailing arm on the car, but I would think that R&R of the bearing races might be tough, but I might be wrong.

[ewenjo]

Originally Posted by Deltacom

It depends on the type of rear suspension you have on your 82 380SL.
See This Thread and let us know your type or pics of your suspension as there are different procedures.

Pictures are attached. Not sure if I have the Homokinetic and the Torque Compensator thing ( not sure of the correct terms)

[ewenjo]

Originally Posted by daidnik

Getting the CV half shaft out isn't too bad. Have to remove the differential cover to pull the retaining clip from inside to get the that out if you want that, but if you're only going to do the wheel bearing, you can just wire hang it with the wheel side disconnected.

I think getting the bearing races out of the trailing arm will require removing the trailing arm. If it's the drivers side, that'll also require disconnecting the drive shaft from the differential to get the inner bolt out. You will need the special 4-prong tool for the nut holding the wheel bearing assy in the trailing arm and you'll need to setup a bolt/allthread/washer setup thru the hub to keep that tool from slipping off the nut. You also have to keep the hub from turning. You could use the brakes with a helper for removal on the car, but putting it back together with a new crush sleeve will be a lot tougher especially if you are going to set the indicate the free-play to 0.002"=0.05mm as you need good control of the tools in torquing those final fractional turns on the nut. I did this off the car.

I made a counter-hold out of an old brake disk by drilling a couple of holes thru the disk and mounting a 4 foot piece of steel 1x1x1/8 square tubing to the disk. Even with two people, it's hard too get that crush sleeve started in compression. After that it's not too bad as long as you don't go too far or then you have to start all over with another new crush sleeve, so that part is tricky and you must use a dial gauge to do it correctly.

Pulling the hub assy out of the trailing arm with a slide hammer can be a pain when the trailing arm is off the car as the arm is a weird shape without any good spot to anchor against. Maybe a chain to an anvil might be good. On mine, I had someone hold it against some wood on the ground and it took me many vigorous whacks with a 5 lb slide hammer to get that thing out. I would think that R&R of the bearing races will require removing the trailing arm from the car. Drifting the bearings out with a brass drift can be hard without a really nice solid anvil or steel table on a concrete floor. You really need that kind of solid impulse in the applied force to get the bearing races removed and solidly seated in installation.

Geez, I forgot to say that you also need the special spring compressor to get the spring compressed and get it out thru the cutout in the wheel well. That job is a pain! I only did it a couple of months ago and I've already forgotten how hard it was. Maybe some do it all with the trailing arm on the car, but I would think that R&R of the bearing races might be tough, but I might be wrong.

Thanks for your reply... you're anguishing me. The Morrison writeup made the job sound much easier although has its difficulties. Your writeup is making me rethink this rear bearing removal. I guess if you don't try you can never have an accomplishment.

[Deltacom]

Hi Ewenjo,

Thanks for the pics. It clarifies the issue. Your model do not have anti-squat (starting-torque-compensator) system but pressed steel semitrailing arms with the hub being integral part of the arm (similar to D.Morrison’s W123). There is no need to remove springs or arms from the vehicle to replace the bearings as the weight of the vehicle itself serves as an excellent workbench to apply the pretty high torque you will need to tighten the slotted nut to compress the new crush washer on the flange.

Your axleshafts are homokinetic with weight balancing rings and they remain attached to the differential (properly supported) while you work on the hub and they can be compressed to push out of the wheel flange once you have loosened the top nuts of the shocks absorbers to allow the arms to drop further down to the stop bracket on the arms (about 10mm).

Due to the limited space under the car to apply the torque needed to undo and retighten the slotted nut, it is more conducive to apply the torque to the hub-flange using a 2-3 foot bar (square/rectangular tube obtainable from your hardware store offers more resistance to bending) as mentioned by Daidnik, and using the wheel lugs (bolts) on the flange as torque pivots to turn the flange allows to apply the necessary torque while using the slotted nut tool on the ratchet to rest against the arm when you apply the torque to undo or retighten the slotted nut.

Here are a few pics to assist you through the process and other guys here will be glad to share their experiences on this particular job. Don’t forget that Moses wandered 40 years through the dessert as he would not ask for directions………


Separation and removal of the outer bearing








More to follow…..

[Deltacom]

Follow up…

Difference between compressed and uncompressed new crush washer


Installing new bearing




Using bearing race tool to install racers





Removing flange (your hub is different and you will use a hammer but it gives you an idea)



More to follow….

[daidnik]

Deltacom,

I would think that part to be tough with the arm on the car.

[daidnik]

Ewenjo,

The suspension design you have on your SL was used on all the /8 era cars which started in the end of the '60's on the W114's I think.

In the later implementations as I'm sure your car is, the limit stop that is on the front of the rear trailing arms, a sort of upside down "L" that contacts a stop on the rear axle crossmember and keeps the trailing arm from dropping all the way down under the spring tension if the shock is removed.

On the later variants there was a design change to from this limit stop being welded to the trailing arm to instead being bolted to the trailing arm and thus removable to facilitate easier repair. This enables the mechanic to drop the trailing arm all the way down with a floor jack to relieve the spring tension. On my '73 220, I have the welded version that is not so easy and thus I used the special 'thru the center' spring compressor which I was fortunate enough to borrow from a friend mechanic. He did tell me that this method of dropping the arm with a floor jack works well and is pretty safe and easy to control.

Once you've got that part dealt with, the job is not too bad. Like the other poster had said about the counter-hold for the crush sleeve, I've heard that the square tubing can also be 'pinned' between some longer bolts thru the lug bolt holes rather than the modified old brake disk I made.

It just takes two people and the dial gauge and use of the failsafe allthread w/ nuts & washers thru the hub to make sure that 4-prong socket tool doesn't slip off as you apply a torque of >200 ft-lb to get that crush sleeve started crushing.

Don't be too dismayed.

If you do decide to do the job like this, I would suggest also replacing the trailing arm bushings. The Boge bushings are around $11 ea (2 per side), and are pretty easy to change.

[ewenjo]

Thanks for all the help. The Morrison report was extremely helpful and particularly the comment by Delta to lower the trailing arm by removing the shock upper attachment. I am well into the rear bearing replacement. The biggest challange thus far was the removal of the outboard end of the CV axle. It just seemed that there was not sufficinet compression to remove the axle. After rereading Deltas comment, I removed the upper nuts on the shock which lowered the trailing arm. This gave just about enough slack to remove the axle. (but still pretty tight)

Removal of the slotted nut was a charm, as well as the removal of the hub. The outer hub bearing was removed gingerly with a chisel and wedge. The trailing arm races were also easily removed with a drive pin.

Pressing the new races into the trailing arm went well using the the old races to drive the new into place.

Tomorrow I will press the outer bearing onto the hub . Since I don't have a press so I have to rig something over the hub shaft to drive the bearing in place. I am a little reticent about getting the inner bearing pressed on. Not sure how I am giong to do this yet. More to follow.

[AlexK]

Originally Posted by ewenjo

Pressing the new races into the trailing arm went well using the the old races to drive the new into place.

Tomorrow I will press the outer bearing onto the hub . Since I don't have a press so I have to rig something over the hub shaft to drive the bearing in place. I am a little reticent about getting the inner bearing pressed on. Not sure how I am giong to do this yet. More to follow.

Re-installing the inner bearing should not be much of a problem, as one of the pictures shows that is can be separated with a pocket knive and chisels. You may need to cut piece of pipe with a precise 90 degree angle.

As for a press, I saw one for $140 new. With a some effort one could build it like a frame out of 6 short 2x4 's, four long bolts and a hydrolic jack.

[Deltacom]

Tomorrow I will press the outer bearing onto the hub . Since I don't have a press so I have to rig something over the hub shaft to drive the bearing in place. I am a little reticent about getting the inner bearing pressed on. Not sure how I am giong to do this yet. More to follow.

Excellent work Ewenjo! You’re half a way there…

A press is very useful and precise but not absolutely necessary. I have put together a rig with a spare flange and bearings for your information and gives suggestions to drive in the outer and inner bearings on the flange. Dont forget to inser the crush washer before you install the inner bearing!!.
Of course, in your hubs you will use the rod to press in the inner bearing once the outer bearing has been pressed in, thoroughly greased, the crush washer installed and the flange inserted in the hub. Be generous with grease before pressing the inner bearing.

From your hardware store you can get the implements to press in the bearings for little cost. Namely: a threaded rod 20mm diameter by 300mm long, 3 30mm nuts, a few 65mm big washers and a length of standard exhaust pipe 50mm external diameter X 47mm internal diameter and 80mm long which should be cut at exactly square angles as AlexK mentions







Congratulations on undertaking this work Ewenjo, one have to remember that.. Your only limitation is how much action you are willing to take...

You did well.

[AlexK]

Deltacom,

I like your approach of the simple tools.
A couple of years ago I had to replace the pin of door hinge. It just would not budge. Finally to the immense laughter of my son and his friends, I asked my son to weld a threaded rod (as on your picture) to the head of the pin, added a couple of sparkplug sockets, washers and a nut, put the whole shebang in the bench Vise, and to their surprise the pin came out.

Also, I remove an innerbearings with a paint scraper. Fits nicely, because of the angle.
I like to use crazy tools whenever needed.

It looks like you are really into the Mercedes.
Would you know if anybody needs a complete Chain Conversion Kit for a 1981 380SL?
Imported from Germany, still in the original packages.
Fits engine 1973 to 1981.

Thanks
Alex.

[ewenjo]

Okay, I finished the replacement of the rear wheel bearings. All went well until I tried to apply the required torque to to set the endplay and crush the "crushable washer" to the required .0015 to .004 inches. The first try I couldn't get the endplay less than .035 inches. I applied significant torque and in fact bent the sacrificial bolts in the hub ( ref Morrison repair). I decided to start anew and remove the hub to see if I decipher the problem. After removal I noticed that the thrust washer ID tolerance was such that it got hung up on the shaft threads and not be able to be pushed onto the shaft to aid in crushing the washer. I relieved the ID of the washer, to assure an acceptable fit onto the axle hub shaft. I reinstalled the hub, and inner bearing. And applied the torque while closely watching the end play. ( magnetic base and dial gauge). All went well after the thrust washer was relieved. The resulting end play is .0035.
Moral of the story: Check the fit of the thrust washer before final assembly.


Test drive felt great as well as the feeling of an accomplishment.

Thanks again for the help.. This forum is great