Owing to age and stupidity, this was erroneously posted on the Series I, II and III saloons forum as well (though it will appply to those cars too)!

Guys
As part of my rebuilding the rear hub driveshaft bearings, now I can report successfully completed, I also renewed the outer wishbone/hub fulcrum bearings.
This is what I am talking about:

Bracket on the lower rear wishbone into which the hub fulcrum assembly must fit quite accurately

Hub casting showing the lower fulcrum

The designed setup works well but is rather tricky to set up and assemble, and there is a slightly easier path than using all the OEM parts. The factory uses a pressed steel cup and a felt washer to keep the grease in and the weather out of the fulcrum bearings. This can be replaced by an oil seal, which means better sealing, easier assembly and fewer parts and spacers needed. This mod is mentioned in the Great Palm's book and works well.

To rebuild and assemble this fulcrum, the first job is to remove everything from the old one. So remove the driveshaft from the hub (can be very hard to do and a big press with a thumping action might be needed, depending upon the climate the car has lived in).
Once the driveshaft is removed from the hub, the fulcrum nuts (15/16ths AF) undo and the fulcrum pin can be slid out. The the entire hub is free from the wishbone and can be lifted off the car. This will leave (most likely) a pressed steel cup and a filthy felt washer still jammed in the casting. Somehow the steel cup must be prised out, which will likely wreck it - doesn't matter.
Then in this order from the outside to the actual bearing race you will find the parts shown in this diagram:

The bits you will need to retain (or buy if they need renewing) to rebuild the fulcrum are:

• 16 the tube-to-bearing shims that are used to adjust the bearing preload/endfloat
• 17 the spacer tube that together with the shims (16) holds the bearings each end at the right preload/endfloat
• 18 the taper roller bearings
• 19 the seal tracks
• 24 the shims between the bearing and the seal track, these are used to adjust the width of the assembly so it fits precisely into the wishbone bracket
• 26 and 28 the end washers and nuts.

These can be bought as a kit from (eg) David Manners or bought individually. The kit will incluse the OEM redundant parts though that might be cheaper than buying the bits individually.

In addition you will need to buy the oil seals. These are a standard Imperial size and are available from Bearing Boys (www.bearingboys.co.uk) very cheaply. The item is double lip nitrile imperial oil seal (BB-99203). Here is a photo of the relevant parts apart from the bearings and tube:

Once all the old stuff is out of the casting, the only thing left is to drift out the old bearing cups:

You need a long thinnish drift

And then clean out the old grease and all is ready to rebuild

Because the bearings only rotate about one or two degrees, the bearings get "brinnelled" which means wear marks appear in the cups. Therefore do not reuse the old bearings. OEM, the preload required is 2 thou, but experts told me this just ruins the bearings and 0 (zero) endfloat/preload is best. Bearing cup damage through brinnellisation:

• Drift in the new cups each end, then with the hub sitting on its wide end
• on one end insert the bearing inner race into its cup
• on that same end insert the oil seal track
• insert the spacer tube into the hub from the other end and slide the pin through the hub, the tube, through the new bearing and oil seal track, and
• use the old bearing inner race as a spacer outside the new bearing you have just inserted, finger tighten the nut onto the pin at the end with the new bearing and oil seal track in it
• then turn the hub on its side so the nut end of the pin is resting on the workbench and the assembly is more or less upright with the end of the pin without the nut on it sticking upwards out of the casting

The way the endfloat/preload is set requires you to slide a stack of shims (the smaller tube/bearing shims in the above photo) down the pin (now sticking upwards out of the open end of the casting) so they sit on top of the tube that the pin is sticking through. Then insert the bearing inner race, the oil seal track, and again the old race as a spacer. The shims come on 3 and 7 thou thicknesses, and I slid 4 x seven thou shims onto the tube. This should be enough to ensure measureable endfloat.

Place the hub on its large end, do up the pin firmly, not stupid tight, and you should find that the pin can be moved sideways across the hub a touch. This is endfloat and needs to be measured with a dial gauge. In my case we had 21 thou of endfloat, so I removed three of the 7 thou shims. This gives 0 zero endfloat/zero preload, which is what I was aiming for. I checked it after removing the shims and all was fine.
Situation so far: The hub has the fulcrum bearings in it correctly set, it has the pin and spacers keeping everything together. Now, the assembly has to be mounted into the wishbone bracket precisely. This involves a second set of shims; the larger shims in the above photo, the bearing/seal track shims

 

Continued from post 1
Here is a diagram of one end of the hub assembly showing the situation:

The endfloat/preload shims are correct (see post 1) but the 'fit into the wishbone shims' that go between the bearing race and the seal track have not yet been fitted. Obviously, if the assembly is loose in the wishbone bracket, all the endfloat meausrement will be pointless, as the bearings will not be held in position. Hub bracket photo:


There is another difficulty: to place the hub into the wishbone bracket requires the pin to be removed from the hub, the hub placed into the bracket and the pin to be inserted through one end of the bracket, the hub, and the other end of the bracket. During which operation all the fine shims will fall out of alignment!

So this is what I did. I bought a few sticks of 15mm wood dowels. I cut them carefully to be as close the the inner width of each wishbone bracket as possible. Then, dowel in the bracket, I inserted feeler guage to get the exact length, so for each side I had one of these:

This dowel is for the left hand side. The bracket interior length is the wooden dowel plus 6 thou.

Back to the workbench, hub on its big end, the pin nuts undone, the pin is pushed out using the wood dowel, so all the endfloat shims, bearings, seal track etc stay in place and we end up like this:

Hub casting on its side, wood dowel replaces pin, everything still in place

Remember, the wood dowel plus 6 thou, is the bracket 'gap' the assembly must fit into. Therefore enough shims need to be added between the bearing inner race and the seal track to make the seal track 6 thou proud of the dowel. The position of these shims is shown in the diagram above. It is easy to pull off the seal track and add the shims leaving the dowel in place.
Now the entire hub, with the wood dowel still in place, is offered up to the wishbone bracket. It fitted exactly! But if it does not, you just add or subtract the shims under the seal track.
Now take the hub back to the bench, carefully remove the seal track and shims from one end and grease up the bearing rollers, leaving the wood dowel in place. Do the bearing the other end.
Next and VERY important, the oil seals must be pushed into place into the gap round the seal tack shown here:

oil seal NOT in place,

oil seal in place, ensure it is pushed just below the level of the seal track outer surface
NOTE: if you are to do the greasing mod suggested below, block up the OEM grease relief hole in the back centre of the hub casting with a small self tapping screw

Then offer up the assembly to the hub bracket, have an assistant hold the thing in place and using the pin, drive the pin through the bracket and into the hub which gradually pushes out the dowel, and continue until the dowel is out and the pin is through the bracket! Thus the shims have no opportunity to fall out of alignment.
This does need careful alignment of the bracket hole and the ub fulcrum to get everything started, but with two people is quite straightforward.
Add washers and nuts and tighten up.

Finally: greasing the assembly.
The bearing rollers have been greased, but the grease nipple has yet to be inserted and the hub cavity filled up. This is where another Great Palm tip can be utilised. In the photo below the depth of the casting to the shoulder the bearing cone sits on is shown:

Depth of casting to bearing come shoulder. The actual bearing cone fills 11 mm of this depth then then comes the roller inner race in addition


Drill a hole, diameter 2.5mm, exactly 8.5 mm down from the top of the casting. In the above photo you can se the bearing roller inner race just below the hole


Hole from the outside, 8.5mm from the end of the casting

As you can see from the middle photo, there is plenty of room above the hole for the oil seal, which is only 6 mm in depth. This leaves a nice cavity which will be filled with grease via the central grease nipple on the bottom of the casting, which must be inserted ONLY once the casting is in place and the driveshaft connected.
Furthermore, before mounting the assembly, screw a small self tapper into the grease relief hole in the back of the casting, so that grease is forced out through the bearings, which you will see exiting the holes!
Job done:

You can just see the seal track nicely against the bracket, as a result of using shims to get the fit with no slop.


Grease coming out of the holes proving that the bearings are surrounded in grease, and more important, will have new grease pushed through them when regular servicing is done.

 

Brilliant write up and explanation.

Needs to "stickied'.

 

Thank for inspiring me to NEVER tackle this project. ha!

But great work!!