Bearing " NIP " on TC rear wheel bearings

[Ed Hosford]

Hi Does any one know what the bearing nip is on the rear wheel bearings ie how much gap to be left between bearing carrier and driveshaft ( 1/2 shaft) cap.

[antijam]

In an ideal world the gap between the bearing carrier and the hub would just equal the thickness of the crushed paper gasket. Personally I would assemble everything 'dry', leaving out the gasket and check what gap there is. If there's none at all (and it does happen) it will be necessary to make up some shims to fit between the hub and the bearing outer race until a positive gap is achieved when bolted up. This can be as small as you like but there must be some gap to ensure the bearing race is clamped. I dispense with the paper gasket and seal the joint with RTV silicone.

[Ed Hosford]

Hi Antijam, from memory the gasket is either 5 or 10 thou so you reckon a nip of between 5-10 thou is sufficient.

[antijam]

Hi Antijam, from memory the gasket is either 5 or 10 thou so you reckon a nip of between 5-10 thou is sufficient.

The only way to ensure the bearing has been rigidly clamped by the hub and carrier is to produce an observable gap between the flanges. There is no point in this gap being wider than necessary and it simply needs to be adequate to accept a sealing medium without reducing the clamp. If the gap is slightly greater than the thickness of the gasket then if this is coated with a sealing compound such as Hylomar for example, a satisfactory seal and bearing clamp should be achieved. If the gap is the same as or smaller than the gasket thickness I'd discard that and use the RTV only.

[Kameron M]

I do not see how the bearing has any effect on the gap between the hub and the carrier at all. The bearing is pressed into the carrier and then is bolted to the differential shaft such that it rolls around the exterior of the differential and is affixed in place much like a spindle setup, and then the hub and halfshaft pass through the center of this spindle via an oil seal ring and the halfshaft is affixed into the center of the differential. When I looked at this, it seemed to me that no part of the bearing should ever interfere with or 'set' any clearances with regards to the hub, that would all have to do with the halfshaft into the differential - which should have PLENTY of clearance, as in 1/4 of an inch or so forward and back. As such, it would only be the machining of those two parts that would effect how closely they would fit together, at least in my humble opine. Perhaps I am very incorrect about this? I ask because I would like to know for myself.

[Richard Michell]

Kameron, if you study a hub you will note that it has a shortish, pipe stub-like, cylindrical portion projecting inboard of the flange. The diameter of this "pipe stub" matches that of the outer race of the bearing. It is there to clamp the bearing into place when the brake drum nuts are tightened. If the tightening results in the two flange surfaces come together before the end of the stub reaches the outer race, the bearing will not be clamped

I have recently rebuilt the hubs on my TC. I used a paper gasket plus clear silicone. Although 6 thou gap between the flange surfaces seemed as though it should be OK, I found that I had to allow 10 thou to ensure clamping. I achieved this by using a shim matched to the outer race.

Sorry for the less than technical terminology.

[dirk w dondorp]

On page 107 of TC's forever, this subject, including drawing, is well described by Mike Sherrell!

[Ed Hosford]

Hi Dirk I dont have a copy of M Sherrells book, does he mention what the Nip clearance is ? Wear on both the stub axle and hub in the way of the bearing are common problem with all Morris 3/4 floating axles from the 1920s Cowley to the MGTC due mainly to the big central nut not being heaved up tightly enough and the lack of clamping on the outer race allowing the bearing to slide about in the hub. I haven't been able to find any definitive figures which is why I posted the original question, I suspect that something like 100lb/ft for the big nut and 10 thou for the outer race is about right, but ?

[Richard Michell]

I don't think the Sherrell book gives a measurement. Doug Pelton in Tech Article CH101 says 4 thou minimum with no gasket or gasket thickness plus 4 thou. Depends, in my experience, on how smooth, etc. your hub flanges, etc. are. As stated, in my case I needed more than 6 thou to ensure clamping on one hub. Other was OK at 6 thou.

[antijam]

This is an extract from p106 of Mike Sherrell's book...

The diagram on p107 is slightly confusing since it shows the result of failing to torque the lock nut to clamp the bearing inner race rather than falure to ensure adequate clamp of the outer. The detrimental effect of both though is effectively the same.

This is a link to CH201 (which I guess is the article you're referring to Richard?) See paragraph 16. This rear seal mod is certainly worthwhile.

[Kameron M]

Ah! Well this would explain why my former wheel bearings were quite toasted and why my rear brake drums were quite soggy with transmission oil. Nonetheless, now I see where the problem comes from, and how to make the adjustment and how to use a feeler gauge to marvellous effect. On that note, if I turn out to require a shim as it seems many people do, where could I go about getting one? Or is this something that has to be custom made?

[antijam]

.... if I turn out to require a shim as it seems many people do, where could I go about getting one? Or is this something that has to be custom made?

I'm not aware of a source of ready made shims Kameron, but steel shim stock is readily available in the UK as I'm sure it is in the States. If you need it at all I'd suggest buying stock around .008" - .010" thick. Once the bearing is just starting to clamp, one more shim will produce an adequate gap for sealing.

Material this thick can be easily cut with scissors (but don't pinch her embroidery scissors - they won't be the same afterwards!). With a pair of compasses mark out on the shim the inner and outer diameters of the bearing outer race and cut out the resulting annular shim - cut the inside diameter first. You may need several shims to achieve the required gap. Elegance of profile is not necessary here - as long as it roughly matches the outer race, all you're after is thickness.

[Ed Hosford]

Anti Jam,
Many thanks for the copy of Sherrells advice , It confirms what I thought. I also agree it was a pity that the factory only told the dealers, as this problem had been ongoing from the early 1920s, the axle ends are dimensionaly the same. only difference is the TC has a separate bearing carrier from the brakedrum which is incorporated in the early Morris cars.
Kameron I concur with Antijam on the making of shims ( he beat me to the reply by minutes ) though you may find brass shim more readily available from model makers supplies. or you could try infofromtheframeup.com as he shows a shim kit in the contents of his wheel seal upgrade ( CH201 )

[stephen stierman]

May I suggest that if you are not using bearing retaining nuts with axle seals built in that you take this opportunity to replace the seal in the bearing carrier and also clean out and degrease the inner section of the splined hub. Then build up several good thick layers of silicone hi temp sealant around the axle shaft where it goes through the hub to keep gear oil from migrating down the axle shaft splines onto your wire wheels.

[Richard Michell]

Yes Antijam - it was meant to be CH201. Sorry, but it was close to midnight here when I typed it! Doug Pelton at FTFU sells a shim set - from memory 2x 5 thou, 1x 10 thou.

[SteveW]

... if I turn out to require a shim as it seems many people do, where could I go about getting one? Or is this something that has to be custom made?

The bearing company (http://www.thebearingcompany.co.uk) stocks a wide range of shim diameters and thicknesses, including a range that is exactly the right diameter to fit the rear TC hub. I got the ones that I needed to do both sides for £7 including postage. Obviously it will cost more to post to the US, but as its only the weight of a letter it may not be too bad compared to having to buy a whole roll of shim stock for just a couple of bits and then having to fabricate what you need.

I'm just about to rebuild the rear axle on my TC. I've used the new hub nuts with the improved lip seal and I've just sent my differential pinion cap to Roger Furneaux to be modified with a lip seal as well. Once its all bolted back together I should have a rolling chassis so that I can work on the car outside if the summer ever arrives.

[antijam]

That's a useful link for the shims Steve - thanks (shame I've already spent time with shimstock and scissors to do mine!) I've fitted the lip-sealed hub nuts and pinion cap too, so am hoping for a relatively oil-tight axle when it's on the road.

I'm in the throes of panel fitting at the moment and the space constraints of my garage make working outside much easier too. Not for the last few days though unfortunately - and it's still raining!

[SteveW]

I'm in the throes of panel fitting at the moment and the space constraints of my garage make working outside much easier too. Not for the last few days though unfortunately - and it's still raining!

Sounds like your a couple of stages ahead of me. Once I've finished the rolling chassis, my plan is to start on the tub. I have a full set of wood ready to make the frame then I'll do the panel fitting. Are you making the panels yourself or have you bought them? I intend to have a go at the front quarter panels myself as these are the easiest, and depending how I get on then either buy or make the rear ones.

If you plan to be close to J26 on the M1 and you have time to call in, let me know as I'm only 5 minutes from there.

[antijam]

..... Are you making the panels yourself or have you bought them? I intend to have a go at the front quarter panels myself as these are the easiest, and depending how I get on then either buy or make the rear ones.....

I've taken the easy (and very expensive) route of buying a new fully panelled tub from Hutson...

.... and new tank, wings,running boards and front apron from Moss. The only original tinwork is the scuttle and bonnet.

This approach has not been without its problems though. The Moss panels are by and large not badly produced, but their profile is not perfect. One example has been the marriage of the running boards to the front wings. In order to get a near continuous flowing line from the front to rear wings I found I had to mount the running boards high at the front and low at the rear. There are three welded-on brackets on the boards for mounting to the body; the high mount at the front meant the front bracket fixing Was fine, but the other two had to be truncated to follow the bottom of the tub. This is the middle one....

...and this the rear.

The red outlines show the position of the slotted holes of the original fixings. There was enough material left in the centre bracket to produce a new mounting hole above the original slot, but here was no material left in the rear one to fix to the tub.

From a piece of scrap steel angle I fabricated a couple of brackets....

...which I fastened to the remains of the rear brackets...

...to be continued....

[antijam]

...before screwing to the underside of the tub...

This position gives a reasonable line with the front wing without too much of an obvious 'kink' at the join....

The lower position of the running board actually ties up pretty well with the bottom of the rear wing which also ended up low after getting its best fit, although it doesn't now follow the door lower profile so well. The new bracket has the additional advantages that its a much more robust attachment to the body and can also take out any 'twist' in the running board which seems a feature of the Moss items.

Getting all the new metalwork to line up optimally is a very tedious process with constant fitting, removing and refitting - and it all has to come apart again for painting! Still, it's some sort of progress..

The M1 is not a normal stomping ground for me, but I appreciate your invite. Should you find yourself near the M4/M5 interchange I'd be glad to reciprocate, Good luck with the rebuild!