The rear hubs and suspension
The rear hubs are big, heavy and have a very large nut that is very tight.
I have removed the entire rear suspension and hubs.
This was done in order to carry out all the body repairs to the rear wheelarch areas. The hubs were dismantled entirely as the brake backplates were completely rotten and to replace them involves the removal of the hub and stub shaft. I wanted to replace all bearings as a matter of course anyway. To dismantle, I started by removing the brake drum which gave access to the brake shoes and associated springs and levers, all of which were removed. I then removed the drive shaft which was going to be rebuilt.
Removing the large nut which holds the rear hub together is a job that would ideally be carried out while the bus is on the ground where you can use the brakes to prevent the wheel turning. As the bus was already on axle stands I could not do this so the hub had to be removed in one piece. Before removing the bolts attaching the hub to the spring plate, mark the hub casing, spring plate and swing arm so that they all go back together in the same position.
The swing arm can now be removed, cleaned, inspected and painted.
Stripping the hub requires the use of a special tool, this is a tool that is used to lock the hub while the hub nut is removed, it can also be used to remove the engine flywheel gland nut.
I made a tool similar to that used by numerous VW owners, it consists of a length of scaffold pole (about 4 feet), this has a couple of holes drilled through it in order for it to be bolted to the workshop floor. I used some 1/2" rawl bolts in the floor. A large 1/4" thick steel plate (8" x 6") is then welded to one end of the scaffold pole so that it sticks up at 90° to the floor. This plate has a number of holes drilled in it, two the same size as the wheel studs so that the hub can be bolted to the plate so securing it to the ground.
The other (three) holes are drilled so that the plate can be bolted to the flywheel using the clutch attachment bolts, which means that the crankshaft and flywheel are bolted to the floor. This allows the same tool to be used for removing/tightening the gland nut.
Now, with the hub attached to the plate and using a 46mm 3/4" drive socket and
a very long breaker bar you can undo the big nut (remembering to remove the spilt pin
The stub shaft will not just drop out of the bearings but needs a little persuasion with a mallet.
With the stub shaft removed it can be cleaned up and inspected for signs of wear.
If you are going this far with the hub, it is just as well to replace the bearings as
a matter of course, even if, like me you keep the old ones as spares.
The rear hub and suspension is simple and clever, it is made up of a drive shaft
from the gearbox which has a stubshaft bolted to one end, the stub shaft has the wheel
hub fitted to the end on the large splines. This is the rotating assembly and it now
needs to be supported. The stub shaft has a machined collar on the inner end which
butts up against the inner race of the inner bearing which in turn butts up against
the inner face of the large spacer, this then butts up against the inner face of the
inner race of the outer bearing. The wheel hub also has a machined collar on it's
inner face which butts up against the outer face of the inner race of the outer bearing.
Confused?...this sketch might help:
I know the bearings in the sketch look like ball bearings, wheras the ones in the hub are roller bearings but at least you can see that they are bearings.
The hub nut 'clamps' the stub shaft, bearings, spacer and wheel hub together, which means that the stub shaft rotates within the bearings and as the bearings are pressed into the hub casing and the inner bearing has a very large circlip holding it in, the shaft will not move in and out of the housing. As you can appreciate, the hub nut is pretty damned tight, it has to be to prevent the bearing inner races or the spacer slipping, so causing wear.
The stub shaft which is now supported in the hub casing now needs to be attached
to the bus. Four bolts pass through the hub casing, through the spring plate and
through the swing arm.
The spring plate is attached to the torsion bar which is the component that 'supports' the vehicle. The swing arm prevents side to side movement of the hub assembly.
The torsion bar, well this is a marvelously simple bit of kit, it does however require careful handling and if you remove one make sure you mark it as to which side it is from, if you don't and you put it in the wrong side, as soon as you put any weight on it, it will more than likely break. The reason for this is that the torsion bars are (I think) identical, they are fitted to both sides of the bus and in order to supply 'suspension', they twist, and as the weight of the bus is there all the time the torsion bars become 'set', so you can imagine if you were to suddenly put this on the other side of the bus and twist it the other way, it is going to get upset!
The torsion bar has a set of splines (different number) on each end, one end fits into the splined aperture in the centre of the large suspension tube that runs across the bus. The other end goes in the splined hole in the end of the spring plate. This end of the spring plate has a 'doughnut' rubber bush fitted to each side and is bolted to the tube by the infamous 'torsion arm cover' that is usually rotten.
Bearings in the hub casing are replaced in the standard way, i.e. light tapping with
a hammer and soft drift to get them out and even gentler tapping using an appropriately
sized socket that is the same diameter as the outer race.
DONT FORGET to fit the spacer between the bearings after fitting the first one, it won't go in afterwards
NEVER hit the inner race of the bearing
Fit the large circlip to the inside of the hub casing.
Pack the hub casing with loads of grease ensuring that the bearings are well packed
Fit the new oil seals, again using an appropriately sized socket to ensure the seal
goes into it's hole square and when re-inserting the stub shaft, try and
press it through enough to get the nut on and then pull it through by tightening the nut.
Before fitting the wheel hub and tightening it up to the full torque remember to fit the brake backplate.
A rear hub before stripping down.
Oh, dear look at all those bits!!
Ok, rear hub rebuilt and ready to fit.