Pictorial - Rear End Rebuild Part 4 - Rear hub strip down and rebuild

[WGB]

When I rebuilt the front end of my 6.9 I found that the right hand front hub had had water ingress in it so I decided I wanted to check all other bearings in case the car had sat in water.
This meant that I wanted to strip all the rear bearings  (and there are five in each side of a torque control rear hub) as well as replace the actual hub bearings as a matter of course. None of them were giving trouble but the kits are not expensive and it was too good an opportunity not to complete the job properly.

Here is a picture of the LH rear hub showing the complexity of the system as used in 450 and 6.9 rear ends.



Here is a picture of the contents of one hub kit with two bearings, two seals and a new inner sealing ring, new crush ring, new locking tab for caliper, and new nut.



Here is the right rear wheel carrier cover popped and the retaining nut in view.



Here is the bare RH diagonal arm sealed against dirt ingress and ready for painting with bushes removed. Bushes will be another post when completed.



Hub with caliper carrier still in position.



Retaining ring and protective cover of caliper carrier need to be removed.



These two 10 mm hex bolts are bolted through the backing plate and into the caliper carrier and ned to be removed.



Caliper puller required quite extreme pressure to pop the bearing. I'm not sure the little 2 armed puller in the manual would work when they get old and rusty.

My 50mm socket with 1/2 inch converter in the end gives the correct distribution of pressure.



Here is the caliper carrier separated from the hub.



This is what is left and contains the hub bearing.



The manual calls for a bracket to hold the hub in a vice but I have used two old wheel studs clamped in the vice to accomplish the same thing



This is the approved rear hub special socket which fits the flat nut used in the rear hub.



Even with that socket on a one metre bar it took all my bodyweight and arm strength to loosen the nut after bending back the holding crimps - this is why the hub needs to be supported securely if you are to have any chance of loosening it.



At this point they manual suggests using a puller to separate the two halfs of the hub but  I could not get enough purchase with any puller I had and I cannot find the one I own  (and I cannot find anyone who has one for sale) that resembles the one in the workshop manual so I resorted to my small press.

A 24 mm socket sits perfectly in the end of the shaft to give the necessary pressure point security.



Here it is all cleaned up and a transmission gear puller being applied to pull off the outer bearing race.



The puller is fully applied and the race is pulled off the axle.



Only the bare axle remains.



There is only a very small lip to get purchase when driving out the bearing races left in the hub but they came out easily enough with a mallet and an old screwdriver.
The old seal is also removed.



New races were driven in with my home collected brass drift .



The outer radial seal had some sealant applied to it's insidemetal edge p and then driven on with a plastic hammer and then greased along with the races.



50 gm of high melting point grease was measured on scales and the races were packed and the remainder placed in the dead space between the races.
The inner race was tapped home and the inner radial seal was tapped home and the shaped washer pushed on and the nut  turned finger tight only.

It needs to be tensioned correctly with a dial gauge once the rest of the hub is assembled and the whole assembly re-installed on the subframe.



That's for another day.

Bill

[TJ 450]

This job is indeed no walk in the park. It's always good to see how it comes apart/goes together.

Tim

[s class]

Excellent stuff WGB.  I did a similar job on my 280SE - which has the much, much simpler standard non-anti-squat rear end.  Removing those hubs certainly is a spectacularly difficult job. 

[koan]

Rear hubs are a big job. I couldn't do the final adjustment and tightening the lock nut, had to take it to the professionals who normally do it on the car.

Think I asked this before (if I did, I've forgotten!), are you replacing the large diameter but thin carrier bearing?

koan

[WGB]

Rear hubs are a big job. I couldn't do the final adjustment and tightening the lock nut, had to take it to the professionals who normally do it on the car.

Think I asked this before (if I did, I've forgotten!), are you replacing the large diameter but thin carrier bearing?

koan

Why couldn't you do it yourself?

I have three options Koan that I see possible

1) set it up while it's in the vice
2) set it up when I have the rear reassembled and before putting it on the car
3) set it up on the car when I am near completeion - at least these 560 drive shafts allow easy removal and replacement of axle shafts in position on the car.

Or of course - get somebody else to do it.

No I am not planning on replacing the large carrier bearing. My RH one seems fine and there is no grating when turned.

I was going to replace it 90 degrees out of previous phase just to put the weight on a different part of the bearing.

As I said at the start of this post I was concerned about water ingress but I haven't found any so far except for the right front wheel bearing.

Bill

[Big_Richard]

I also couldn't do the final adjustment, ie crushing the crush washer.

I had a 5 meter extension and put my whole body weight on it, it 100kgs and it still wouldn't crush.

I ended up throwing away the complete trailing arms in disgust and now have the complete w126 500sel trailing arms on mine from nathans late parts car. (Same part number+ identical anyway)

[WGB]

Did you do the replacement on or off the car MT.

Bill

[s class]

On my 280SE, I torqued the slot nut to compress trhe crush ring in situ on the car.  The drive shafts were removed at the time. 

I have the same special socket as WGB and it did a great job.  Certainly takes a huge amount of force though.  And its time consuming, because one wants to torque it a fraction at a time, and constantly check the end play with a dail gauge so as not to end up overdoing it. 

[Big_Richard]

i attempted to do mine on the car.

no matter what i did the crushable sleeve would not crush.

I also have the correct slot socket and ruined it in the process. The bits that go into the slots are twisted.

I will never attempt this task again in my life time 

[WGB]

I will never attempt this task again in my life time 

I have spent a few hours thinking about this today and the fact that it is difficult makes me more determined to succeed.

I am going to tighten it on the bench as my vice is reasonably sturdy and can be rotated 360 degrees in two planes which means I have more than one way to "skin a kangaroo".

I am also going to make the holding method a bit more rigid to give myself a more even chance.

If I F##k it up all I will have lost is a crushable sleeve and as the LH side appears not to have suffered any damage I still have a spare one if I gutless out and decide to leave well alone on that side.

But not today Josephine.

Bill

[Big_Richard]

I have no doubt you will succeed where i failed.

I think if i did it again these days id somehow "precrush" the sleve on there with my press, or simply reuse the old one (dodgy as hell i know, but it works in an emergency )

[WGB]

I think if i did it again these days id somehow "precrush" the sleve on there with my press, or simply reuse the old one (dodgy as hell i know, but it works in an emergency )

I am not sure the crushable sleeve is totally necessary.

the bearing setup is really only the equivalent of a front hub and that survives quite well without one.

It may be that it gives some longevity without the need for adjustment or that the force required to crush it makes sure the races are properly seated  but it is still only two opposing tapered races with a locking nut.

I have been toying with the option of initial setting up without it, measuring it all and then doing final tightening with the sleeve in place. This will at least show how much actual crushing really goes on.

I need a clear head and some time so it is not likely to happen until next weekend.

Bill

[s class]

The manual shows the hub being prevented from rotating by means of a plate that attaches to all 5 wheel bolt holes.  I made a similar makeshift tool out of an old brake disc.  I think this is important in order to properly spread the load across the hub and avoid damaging it. 

[TJ 450]

The old brake disc is a great idea.

It sounds like a lot of force is required.

Tim

[koan]

Why couldn't you do it yourself?

At the time I didn't have the four prong tool for the nut, removed the old one with a punch.

The carrier bearings on my hubs rotated but where tight,  fine when removed though, did the same 90 degree rotation. Considering the forces involved I didn't think the tightness mattered.

koan