Rear wheel bearings.

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martinng
Posts: 147
Joined: Thu Oct 10, 2013 5:31 pm

Rear wheel bearings.

Post by martinng »

Today I started on the task of replacing a rear wheel bearing that was identified with too much play during the MOT.
As a newbie when it comes to these apparently simple tasks I tried to find information about this task on the forum and there was very little. Lots about final drives and differentials, but little about rear wheel bearings; presumably considered too routine to describe. One excellent piece of information was from Ian Judd (Forum "A few questions 22/11/10) advising that the seal between half shaft flange and hub can be broken by using drum-brake screws in the two additional holes in the half shaft flange. This avoided damage from trying to drive in wedges etc.
Breaking the half-shaft seal
Breaking the half-shaft seal
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I then removed the half-shaft having (correctly it seems) assumed from what little I had read that this could be pulled out without disturbing the final drive gears. At this point there was clearly no oil seal or washers beneath the layer of thick grease. Neither was there a seal within the axle tube. (NB. The brake shoes wrapped up at this stage to prevent oil contamination).
Drawing out the half-shaft
Drawing out the half-shaft
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Next the tab on the tab washer was bent away from the groove in the hub nut, the hub nut removed with a 'C' spanner, the tab washer removed and with a hub puller the hub bearing housing was removed. So far all was well, but throughout there was still no evidence of any oil seals or felt washers.
Inside the rear of the hub bearing housing there was a steel washer (about 66thou thick) that lifted out of the hub. This does not seem to be listed in the parts lists so its presence is a bit of a mystery. The rear of the bearing housing also has a groove cut in it, but no evidence of anything locating in it.
Hub, washer & groove
Hub, washer & groove
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So I now need to find the means to remove the bearing from the housing, press in the new bearing and then re-assemble.

So what oil seals should I use? The half-shaft / hub flange was located on the bearing housing with a paper seal and gasket jointing compound and there was no evidence of oil or grease in the brake drums. I will be using a sealed bearing, so that will not require grease, I am advised. I will use a paper washer on the flange, but how thick should the paper be (0.4mm is readily available) and should I use a jointing compound? I will replace the steel washer at the back of the bearing, is this a thrust washer? Where should the 'rear hub felt' washer be assembled? Presumably at the back of the bearing but where in relation to the steel washer and the groove?
Groove in hub.
Groove in hub.
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Do I need to introduce a cork or modern plastic seal in the axle tube?
I can find no clear drawing or description of the assembly of the rear hubs in any of the Morris Minor literature that I have found. The closest is on page 168 of John Nagle's "The Complete Morris Minor", but it really only mentions the cork bushes used in the end of the axle casing.
I would be delighted if someone can help with answers to what I hope are fairly straightforward questions to those of you who have experience of this job.
Ian Grace
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Re: Rear wheel bearings.

Post by Ian Grace »

Martin,

Just got up so will answer in full in an hour or two!

Basically everything is fine but you will need a felt seal behind the bearing and a seal in the axle casing. More after breakfast!

Ian
Ian Grace
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Re: Rear wheel bearings.

Post by Ian Grace »

Martin,

First - removing the bearing from the rear hub. The trick I use is to employ a socket from my socket set and a hefty mallet. The larger one are usually stepped, so you should be able to find one whose narrow part fits inside the bearing, and whose larger diameter just fits through the bearing carrier. Place the carrier studs down on a block of wood (to protect the stud ends in the next step), drop the socket in and the carrier and administer a firm blow and repeat as many times as is necessary to drive the bearing out.

A similar technique can be used if you have a workshop vice whose jaws are large enough.

The good news is if you need to drive the bearing out, it hasn't been loose in the carrier, so your carrier is probably OK.

Next is that 66 thou washer - a vital component that is often missing. It protects the felt seal from the bearing. Without it, the felt seal faces directly up to the rotating inner component of the bearing.

Next is the felt disk itself that should sit in another thin steel seating with an outer lip. This lip has a small tab that sticks out and prevents the seating housing from rotating by the heads of the backplate bolts.

You have probably guessed by now that there should be a felt seal sitting in this housing!

When fitting the new seals, they should be lightly oiled to prevent friction if they were to run dry.

Now to the axle shaft seals. Minors were not fitted with any seal in the axle casing originally, so oil from the differential found its way to the felt seal, and eventually through it to the brakes. This was addresses, I believe, with the Morris 8 by adding a cylindrical cork seal with an internal helical scroll to 'pump' oil back inboard. They were glued in to the axle just inboard of the hub. The aftermarket then offered the same seals to the earlier Minor, M Type and Hornet owners.

These days we use a modern plastic material and pairs are available from Mike Dowley. Just be careful to fit them as marked so they pump oil inboard and not into the hubs!

An even better solution is to acquire two pairs. Then you can fit two in each end if the axle with a half inch gap between them, then drill a small hole through the axle casing between the seals so that any oil getting past the first seal drains to the road.

Does that cover everything?
martinng
Posts: 147
Joined: Thu Oct 10, 2013 5:31 pm

Re: Rear wheel bearings.

Post by martinng »

Thanks Ian, that covers most things, but I am a bit confused by your description of the felt washers. I can understand that there is a felt washer in the back of the housing that is protected from the rotating bearing by the 66thou washer. However, is this the same as the felt disk with the thin metal seating and with the tab? If this disk is supplied with the seating and tab, then presumably when I get one it will be clear how the lip locates. I can imagine that this might locate in the slot in the axle casing that also takes the tab of the securing tab washer, but at the moment (with the car away in the garage and me sitting in the living room) I cannot see how a washer within the hub or bearing assembly can protrude sufficiently to reach the backplate bolts.
Finally is a paper washer necessary when refitting the halfshaft / hub and what gasket seal if any should I use? It seems to me that the paper gasket and gasket sealing compound that I found between the halfshaft/ hub and the bearing assembly might be one reason that no oil had escaped from the bearing even though there were no seals.
Many thanks for all the help and advice.
Martin
Ian Grace
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Re: Rear wheel bearings.

Post by Ian Grace »

Martin,

The felt seal comes as a simple ring of felt - no metal parts.

The cupped steel housing it sits in has a piece of the edge cut and bent flat - so it protrudes beyond the outer radius of the housing. It is this tab that reaches out to the bolt heads.

Here's a page from the Minor Manual. Note in the photo at lower right that the backplate bolt heads are very close to the outer radius of the felt seal in its housing (arrowed).

Note also the method of easily removing and replacing the brake shoes by passing a length of string (I use wire) through the hook at the end of the brake shoe return springs.)

Image
martinng
Posts: 147
Joined: Thu Oct 10, 2013 5:31 pm

Re: Rear wheel bearings.

Post by martinng »

Thanks for these pictures Ian. There is certainly no retaining washer of this sort in the hub at the moment and from the pictures, the felt washer in its housing seems to be a much larger diameter than the internal diameter of the bearing housing, which means that it will not come into contact with the 66thou washer deep within the recess of the bearing housing.
I could be wrong, but wheras you have just had breakfast, here it is midnight so I'll have another look at my hubs in the morning and get this worked out.
Martin
martinng
Posts: 147
Joined: Thu Oct 10, 2013 5:31 pm

Re: Rear wheel bearings.

Post by martinng »

Ian, another day with the bearings and no success at pushing out the bearing (using a car jack wedged between the walls by the garden gate!) or beating it out with a hammer (which I was not keen on) so off the local car workshop.
However as far as seals are concerned, I think that I have a very non standard bearing housing. It seems to be made of two parts (is that usual) as though someone has braised on a top section to hold a nitrile rubber seal in place of the felt washer.
Close up of bearing housing
Close up of bearing housing
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Not sure how clear the words are. The top arrow shows the width of the rubber sealing ring with the sealing lip innermost, the second indicates width of the metal / rubber composite seal that has been pushed in. The next labels the bearing ID and the bottom arrow shows where the joint line appears to be in the housing construction. You can see the change in colour of the sections of the housing.
Is this type of seal the so called 'lip-seal' that is a modification used on Morris 8 or perhaps this is an MG modification?
Either way I will get the bearing pushed out and hopefully not damage this seal and I can see better how it is constructed. It does not seem to be listed in Ian Harris's parts list so I will probably need to reuse it. I will then add axle shaft seals and use a sealed bearing in order to minimise grease in the hubs and hopefully all will be well.
Oh and I imagine that the 66thou ring, which I shall also replace, is a spacer between the inner face of the bearing and the axle tube / backplate to take up the load when the hub nut is tightened down.
Very interested in your comments on this.
Martin
Ian Grace
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Re: Rear wheel bearings.

Post by Ian Grace »

Well, this is definitely a modified rear hub. Presumably it would be possible to remove the mod? Are they the same on both sides?

As I understand it, the shim sandwiched in the carrier by the bearing is there to separate the felt seal from the bearing, and also maybe to keep the grease in the bearing. The felt seal carrier between the felt seal and the backplate is there to hold the felt seal and prevent it from spreading.

If the weather was nicer, I'd jack my saloon up, whip the bearing carrier off and take some photos, but it's dumping down out there right now!
martinng
Posts: 147
Joined: Thu Oct 10, 2013 5:31 pm

Re: Rear wheel bearings.

Post by martinng »

I don't know about the felt seal Ian. it seems to me that with the nitrile rubber seal, it was probably never intended to use the felt seal as part of the modification.
As I said, I assume that the spacer ring is so that the inner part of the bearing is pinched up against the axle tube or maybe it would be the raised flange on the backplate where the axle tube emerges from it. The brakes were absolutely clear of any grease or oil, so this modification seems to be well engineered by whoever did it, so I can see no advantage in undoing it. I haven't checked the other side and on the basis that "if it works don't fix it" I can see no reason to start pulling that hub apart, particularly as the driveshaft flange is 'glued' to the bearing housing with a paper washer and gasket sealant so would be difficult to re-seat without compete removal and cleaning up the mating surfaces etc.
Perhaps I will have a chat with James Wheeler, he may well have been responsible for the modified design or at least know about it.
Once I get the old bearing out, I will reassemble in the same order as I took things apart, except that it would be prudent to add the axle seals with the spiral groove as you suggested.
Thanks for this chat, it has certainly helped me to see more clearly how this all works.
Martin
PS. Just bought a 1930 Minor Instruction Manual on e-bay so might get some additional info, but only on the standard design of course.
Ian Grace
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Re: Rear wheel bearings.

Post by Ian Grace »

Martin,

Here's the axle seal:

Image
peterb
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Joined: Mon Mar 24, 2008 9:30 am

Re: Rear wheel bearings.

Post by peterb »

The near-side cork bush has the oil return thread cut in an anti-clockwise direction.The off-side bush thread is cut clockwise.
Harry Edwards published a do-it-yourself technique for making seals.
Attachments
Cork seals.jpg
Cork seals.jpg (167.37 KiB) Viewed 6268 times
sv4670
Posts: 72
Joined: Wed Jan 18, 2012 12:15 pm

Re: Rear wheel bearings.

Post by sv4670 »

Reading this with interest as I am in the process of rebuilding a rear axle: - when I resolve the problem with the back plates.
The bearing came out of my hub using the technique suggested by Ian Grace without problem. If replacement bearings with integral seals are availabe then all the problems with felt seals etc. go away. I presume they are not otherwise this would have been suggested I expect.
Trevor Wilkinson
Posts: 161
Joined: Sat Dec 02, 2006 4:44 pm
Location: Bedfordshire UK

Re: Rear wheel bearings.

Post by Trevor Wilkinson »

I personally would at least have the axle shaft seal,( I actually have sealed bearings,felt seals and shaft seals) belt and braces is best! :wink:
martinng
Posts: 147
Joined: Thu Oct 10, 2013 5:31 pm

Re: Rear wheel bearings.

Post by martinng »

Well I have had some success today. I took my bearing assembly to my local garage and they pushed out the bearing (1.5 tons) on their hydraulic press - no wonder I was unable to shift it.
The top of my very modified bearing housing does have a ring brazed on it (hence the ring of gold coloured braze material) that holds the non-standard nitrile rubber oil seal which acts as a replacement for the felt washer.
They also pressed in the new bearing which is of the sealed variety from Ian Harris. We stopped the press at about 1.5 tons so as not to split any of the brazing and at this point the bearing seemed to be inserted as far as it wanted to go.
So I agree with Trevor. I have a sealed bearing, the nitrile rubber oil seal (in place of the felt) and I will fit the axle seals which I have ordered today from Ian Harris. I also favour using modern the plastic friction fit seals, because the need to clean off thick grease from within the axle tube and axle in order to glue the cork in place might be problematic.
So my view is that there will be less grease in the hub to escape round the rubber ring and the axle seals will remove any possibility that grease from the axle will penetrate the brake drums. (Famous last words!!)

Thanks all for the help and suggestions. This has been quite a learning curve, (and I still don't get to see how the felt washer fit!) so let's hope it's downhill from here.
Martin
Trevor Wilkinson
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Joined: Sat Dec 02, 2006 4:44 pm
Location: Bedfordshire UK

Re: Rear wheel bearings.

Post by Trevor Wilkinson »

My experience with the modern (not cork ) seals is that they fit like a "Pr#c'k in a Shirtsleave" and need some shim steel or thin tin plate to make them fit!
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