Refitting front hub

[luvvaminor]

Hello. I apologise if this one has been done to death but I can't seem to find an answer to my particular query. I have had to change the swivel pin, (kingpin, upright) due to extroadinary play in especially the top trunnion. I have a nice new assembly from ESM. The hub with bearings intact came off easily. The bearings seem all right. The spacer is sliding about a little between the bearings. After cleaning, can I just drift this whole assembly on to the new stub axle (it is tighter than on the old one) by tapping around the centre of the outer bearing? I think the forces would go through the spacer to the inner bearing and I would not be applying unwanted side forces?

[bmcecosse]

Basically - yes! But it shouldn't be tight - it should just slide on as easily as it slid off the old kingpin. So - check for any rag or burr on the stub axle. If you have any means of accurately measuring the stub and comparing with the old one... You should ask ESM if you have any problems... Hope you took the opportunity to fit polyurethane bushes in the top trunnion eye !

[luvvaminor]

Thanks for your reply bmcecosse. The new stub is 25.1mm, 4 thou up. The old one is a maximum of 25 dead and in some places is as small as 24.93. I'm using a caliper, which is not ideal so I took a lot of sample readings. I suppose some wear or flattening occurs on the stub even though nothing rotates on it. Do you think I'll be able to tap it on? On the subject of bushes, I haven't put the leg back on yet but the ESM kit has rubber bushes. Not too bad a job to change in the future but how long might they last? Perhaps not worth fitting.

[bmcecosse]

WELL worth fitting poly bushes in that top trunnion eye. I think you will struggle with 25.1 mm when it should be 25mm - the bearings are to an exact size and won't 'give' at all. You could try the king pin in the freezer over night to see if it shrinks enough. Not really practical to heat the grease filled hub too much - but you could make it 'warm' I suppose. Maybe better to query it with ESM rather than ruin the bearings - and the stub.

[luvvaminor]

Oh, things beginning with "b", and not bearings... I will contact them. I need some more stuff anyway. Including poly bushes!

[bmcecosse]

If you do try to shrink the king pin - be sure to fit the backplate before pushing the hub on !

[luvvaminor]

Thanks - I would almost certainly have fallen for that! I am going to do more investigating tomorrow, and I may have to apologise to ESM.

[luvvaminor]

Ok, I put it in the freezer as suggested. But even before that, last night I had obtained the correct reading of 25.00mm by holding the vernier caliper flat against the boss at the back of the stub axle. This morning I am easily getting readings of 25, even a little under in other places along the stub, so I indeed have to apologise if I impuned the machining of the ESM part. I would add an embarrassed face if I could work out how... Their measuring SHOULD be more accurate than my fumbling attempts, after all! Unfortunately having dissolved all the grease out of the hub and bearings, I find that the inner race of the outer bearing moves in various directions whilst the outer race is stationary within the hub. I assume that this is terminal for the bearing so I need to get new ones. I intend to keep quiet for a while until the job's done.

[bmcecosse]

Just grease up the bearing and hold it straight as you push the hub on. Why did you 'dissolve' out the grease?

[luvvaminor]

Er...well, sorry Sir... I thought it best to get rid of all the old grease although it wasn't badly discoloured. I used petrol. I thought, nice new grease... You always seem to be saying, ha'p'orth of tar etc. Are you going to tell me that the inner race of a bearing can float a bit when it's not on the axle? I understood from everything I have read here that NO "play" is acceptable. When I was young I'd have stuck 'em back on and hoped for the best. How does one define "play"?

[bmcecosse]

You'll only know if there is 'play' when you fit it all back on the stub axle.

[luvvaminor]

Tightening down the hub nut would stop the middle race from moving in the manner I described. So are you confirming that movement of the centre race, when the bearing is not fitted, is no problem? This may seem basic to you, and I am not totally unmechanical, but I haven't done much with bearings. I've got new bearings coming. If they seem the same I will probably use the originals. This is where you need to be able to give the part to someone, and they say, that'll be fine, mate.

[bmcecosse]

Often the 'new bearings' are poor quality, with excessive clearance. Avoid - unless from a bearing specialist. Good old bearings seem to last pretty much for ever. I have NEVER in many years of Minor running had the slightest problem with front (or rear) bearings ! Grease and assemble - and don't overtighten the hub nut.

[mike.perry]

Oversize stub axles do happen. I bought a swivel pin from a well known supplier (no not that one) and found that the wheel bearings would not slide on. I tried the bearings on several old stub axles with no problems so it was definately the stub axle.
I know that I should have given up and sent the part back with a strongly worded letter but it was a Saturday afternoon and I needed the car on Sunday for a rally so with a lot of brute force and plenty of ignorance I forced the bearings on, realizing that I would also have the same trouble removing the brake drum (this was a Series MM wth integral bearings modified to fit M1000 swivel pins). I had to make up a special puller to fit the wheel studs and eventually managed to force the drum off.
I recommend that you do not try this at home

[luvvaminor]

Thanks chaps. The bearings I am expecting are supposed to be FAG. They are reckoned to be good, aren't they?

[luvvaminor]

I've been reading up on angular-contact bearings and for the first time in my life I
understand what "preload" is. Anyway: why didn't I think of this two days ago (or,
to forestall what bmcecosse might say, before taking the suspension apart). I think
the movement in the trunnions would have made early bearing assessment difficult. I
have clamped my old leg in the vice and fitted the hub and old bearings, which go on
easily. I didn't torque the hub nut, just a good pull on a 9" bar - not too tight. I
spun the hub, it turns with an even "swish" sound. I heaved the hub up, down and
sideways and I can not hear, see or feel any clicking or movement. I put the wheel
on, still in the vice and spun it. If anything it is quieter than with just the hub.
There is no grease in the hub and I think it would tend to be noisier without. I
heaved on the wheel as before and still can detect no movement. I don't believe I
need the new bearings after all. As bm said.

[bmcecosse]

Indeed not.... Sounds grand to me.

[luvvaminor]

I've been blocked, apparently!

[luvvaminor]

Having said that, it posted! For several days I've been getting a message that I'm not allowed to post because I'm on a "spamhaus'" blacklist. This was the only site affected, it wasn't my IP address they were quoting and when I looked it up it wasn't a blacklist, just a list of all dynamic addresses. Anyway: bmcecosse, thanks, I was just going to ask something. I got the hub back together with the original bearings after much polishing back and forth with strips of emery and some deburring of the shoulder near the thread. I had some trouble getting the tightening torque correct whilst aligning the split pin hole. Tightening the nut seems to have some effect on hub spin resistance although it feels smooth. Is that a no-no or is it merely the effect of preloading?

[bmcecosse]

There shouldn't be any pre-load, the centre spacer sets the running parameters of the bearing. The torque setting is low - just ease off back to the nearest pin hole and fit a new pin. Check it after a week's running.