MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Rear Hubs and BBBBBBBBBBBBB....

Is it safe to mention Bearings? Rear Wheel Bearings!!!!

I've said it now so I will continue. But before going too far let me tell you what I have been up to today.

I replaced the diff on our Frog with a recond one with a 3.7:1 ratio due to a new Crown wheel and Pinion being fitted. It's a true 3.7, not a midget 1500 3.707, and supplied by the MGOC.

Apart from the fact it was reluctant to go int hole int axle and the CRAP diff gasket supplied by that company that rhymes with TOSS, it all went well. Until, I noticed the RWB was very loose in the hub. So much so that I could hold the outer still with finger pressure and still rotate the hub.

Is this correct? I checked the other side and it was the same.

I've heard the thickness of the gasket is meant to give the correct amount of pinch to the outer of the bearing but judging by the amount of push pull movement of the bearing in the hub I'm not sure how this would be achieved.

Any one shine a light on this?

Rob



Rob aka MG Moneypit

You are right Rob, the outer race should not turn in the hub. And yes, with the correct (thin)paper gasket the flange of the half shaft should pinch and grip the bearing. But the little countersunk screw is only to locate it, it doesn't provide sufficient clamping action. This is supposedly achieved when the wheel nuts are tightened on. So you could try putting the wheel nuts on - without the drum but possibly with spacers of some sort? - and see if the grip action is improved.

If the bearings have been turning in the hub they may have worn themselves loose. I assemble mine with a fair dollop (technical measurement) of bearing fit locktight which seems to do the trick. I have seen them assembled with tin foil/ cigarrette foil / Kitkat wrapper wrapped around the bearing to take up wear, but that isn't a recommendation!

I am sure you are safe mentioning wheel bearings. I strongly suspect that HWNMNBM (he whose name must not be mentioned)would be squirming in his Consul Capri, but that is as near as he is likely to get - unless of course he is reicarnated in some other form.;-)
GuyW

Rob, if you are interested I have recently created a kit that compromises of several different gasket thicknesses, allowing the user to select an appropriate thickness gasket to allow the correct "pinching" of the rear bearing.

I found when I did my bearings, the usual kits only contain one gasket that I found waaaaay too thick. I have a CNC cutter, so set to work making up my own gaskets.

In extreme cases you might have to run without a gasket, just the o-ring.

Mail me on malcolmlechevalier at gmail.com, I have been looking for a guinea pig!

Cheers,
Malcolm
Malcolm Le Chevalier

I'm not sure what BMC, or whoever design the axle intended, but bearings are frequently a press fit on shafts, or retained by a nut in this case, and the outer race is a close sliding fit in the housing to allow for assembly. The friction of bearing race to housing being greater than the torque to turn the inner race and with the gasket to help clamp it the outer race stays put. Anyone have a workshop manual that indicates whether the bearings need to be pressed in or not?
David Billington

I'm guessing your Frogeye does not have a 948 under the bonnet, Rob.

I should know, having been on this board on and off for so many years, but I confess I don't know who HWNMNBM is either.
Nick and Cherry Scoop

I remember having to drift the bearings in, using the old bearing. But I can't remember where the interference was.

They were very light taps though, and you could easily convince yourself that a further clean-up might allow them to sashay in by themselves.
Nick and Cherry Scoop

Thanks for all the replies.

It looks like I have used two excessively worn hubs. As I mentioned I can grip the hub and there is significant movement if I push/pull along the axle. So much so that the edge of the outer is below the face of the hub. The only way that the round plate on the end of the half shaft could grip the outer is if there was significant deformation, which I'm sure doesn't happen.

It could also be the cause of a persitant problem I have had with this axle. Namely, the drum rubbing on the back plate. I have washers on each wheel stud between the drum and the half shaft in an attempt to minimise this. It still does it during enthusiastic left handers.

Engine is 1275 +60, 286 cam + MG Metro bigvalve head and not a lot more. It's the way the engine came to me from David Smith IIRC, I just refreshed it with new rings and bearings and it puts out about 85 bhp according to Peter Burgess rolling road.

I've got several sets of rear hubs so I think I will change them before venturing off to Le Mans next month.

Malcolm, I'll contact you later this week. Got to get on with the car while I have a couple of days of holiday left.

Rob
Rob aka MG Moneypit

Malcolm. I just picked up on your ebay ventures. Looks very reasonable so I may order a couple from you.

Rob
Rob aka MG Moneypit

Guy. I've often wondered if HWNMNBM would assume a new identity and start posting again, but I haven't noticed anyone amongst the newer contributors who have the same sort of abrasive attitude. I sometimes do miss him though,as,even though he could be a PITA at times, he did make some valuable contributions to the proceedings.😈
Bernie Higginson

Rob

I was going to say that I have some spare hubs, but it sounds like you don't need them.

I did have a problem with rear hub bearings on the race car - they would have a lot of play in a very short time.

I ordered a large number of RHP bearings through a friend who had an account with a bearing supplier, but they were so good that I only actually fitted one pair and the others have since been sitting on the shelf ever since.

If you want some top quality bearings, let me know.


Dave O'Neill 2

Thanks Dave O' but as I'm going to Tatton Park show this Saturday I had to get my bits pretty sharpish.

I dug out my spare rear hubs an blow me, all were for wire wheels! Anyway, they looked identical apart from stud length so knocked all the studs out of them and fitted the longer studs to the spare hub.

Fitted oil seal and had to press the bearing into the hub. A good sign as the old ones I could fit and remove the bearing with finger pressure. I used my large bench vice and an old bearing as a spacer and it just slipped in nicely.

Fitted the hub to the axle and it felt a lot tighter all together. Fitted the nut, halfshaft and drum and no scraping noise as there was before. So, something wrong with those old hubs I think.

I'm doing the drivers side today. The weather looks better, good chance of sunshine.

Rob
Rob aka MG Moneypit

Dave, it makes me wonder what sort of tolerances other manufacturers work to. I know during my time with them that several customers went elsewhere but soon came back because they couldn't get consistent quality elsewhere. I remember us having a new Swedish grinder for making rollers to replace the orignal ones from about 60 years earlier. The manufacturer came over as we couldn't get the results we wanted and when they saw the tolerances we worked to they couldn't believe it. Needless to say we never had any more and continued with the old machines.



Trev
Trevor Mason

This thread was discussed between 31/05/2016 and 02/06/2016

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.