Wheel Bearing Greasing & Torquing

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MichaelBeck
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Wheel Bearing Greasing & Torquing

Post by MichaelBeck »

Hi All

Couple of Qs around wheel bearings.

1)Following packing and installation of wheel bearings do you fill the balance of the space with grease or is the quantity in the bearing with a coat on the spindle enough?

2) When tightening a bearing I understand you torque it, back it off, torque etc and tighten it finally before backing it off. From a technical point of view why is this done & what does it achieve?
I understand rotating the hub to seat it - That makes sense but I am interested to know why the tighten-loosen-tighten sequence is needed?

Thanks for your help
les
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Re: Wheel Bearing Greasing & Torquing

Post by les »

When packing a bearing, do just that but there must a reasonable air space, not completely full of grease. The only reason I can suggest for tightening then slackening off, would be to make sure everything is fully seated before final procedure, although the seating should be achieved when installing the bearings in the first place. The tightening and backing of thing is usually associated with taper bearings, and I wouldn’t have thought torque was necessary, rather just tightening reasonably then backing of the required amount.

simmitc
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Re: Wheel Bearing Greasing & Torquing

Post by simmitc »

What sort of bearings do yo have? Standard Minor ball bearingss are not backed off, but if you have discs with taper roller bearings then it is essential that they do have some play.
MichaelBeck
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Re: Wheel Bearing Greasing & Torquing

Post by MichaelBeck »

I have standard bearings , not taper roller or anything such as that.
The question was poorly worded - I should have asked for a how to tighten different types of bearings & the reasons for the differences.

Thanks
MichaelBeck
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Re: Wheel Bearing Greasing & Torquing

Post by MichaelBeck »

Any one clued up on my question above?

Thanks :)
paul 300358
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Re: Wheel Bearing Greasing & Torquing

Post by paul 300358 »

I have recently fitted Midget disks and used second hand hub on the nearside. I removed the standard bearings by freezing the hub so that the bearings just pushed out (bearing has a higher coefficient of linear expansion than the hub). On the nearside I re-greased with a low melting point bearing grease, pressed in the outer bearing, smeared the outer surface of the spacer with grease to pack the space between the spacer and hub, pressed in the inner bearing and seal. I did not pack the area between the bearing and seal to allow for expansion of the grease. I then wiped a thin smear of grease on the shaft, fitted the hub and disk, fitted the nut and washer tightened the nut till it felt right and fitted a new cotter pin (split pin). I never felt the need to tighten slack and retighten the nut.
I did fit new bearings on the offside but now have movement in the bearings, I think that the hub face is worn as the inner bearing nearly fell out of the hub, I have a new one arriving today. I have yet to decide which bearings to fit, I know that a bearing specialist in Crewe stocks the original R&M bearings with the brass cage, correct angle and correct 2mm radius, but they are about £100 a side (probably + VAT).
philthehill
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Re: Wheel Bearing Greasing & Torquing

Post by philthehill »

The hub must be torqued to 40 lb ft. Tighten the nut to get everything seated, back off the nut then torque to finish.

You may find that the spacer between the hub bearings needs to have a thin skim taken off one of the end of the spacer or if you have spares spacers swop them around until the play is eliminated.

Not all spacer are the same length and not all bearing inner races are all the same thickness so sometimes you have to adjust the fit to get it right.

I would recommend that you pack behind the lip seal to give some lubrication to the lip. The void between the bearings does not have to be fully packed - just enough to provide adequate lubrication.

Make sure that the thrust faces are the right way round.
Drawing courtesy of IslipMInor
Islip bearing orientation.jpg
Islip bearing orientation.jpg (40.53 KiB) Viewed 1367 times

paul 300358
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Re: Wheel Bearing Greasing & Torquing

Post by paul 300358 »

philthehill
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Re: Wheel Bearing Greasing & Torquing

Post by philthehill »

I note from the above link that the stub axle nut torque for disk brake applications is 46 lb ft. which is the same as quoted in the Haynes Manual for Midget/Sprite.

I also note from the Haynes manual for the Midget/Sprite that the torque for the drum braked version of the Midget/Sprite is 55 - 65 lb ft

The BMC Minor 1000 wksp man says 40 lb ft. The Minor 1000 stub axle bearing arrangements are virtually the same as drum braked Midgets/Sprites. So why the quoted variation in stub axle torque settings when the bearings and spacer are the one and the same?

Bearing inner - Midget /Minor 1000...……….GHB129 (MOSS)

Bearing outer - Midget / Minor 1000...……..GHB128 (MOSS)

Spacer - Midget / Minor 1000...……………….88G321 (MOSS)

The bearings and spacer are the same part numbers (MOSS) for the 1275cc and 1500c Midgets when fitted with disk brakes.

I must be missing a point somewhere.

Phil

paul 300358
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Re: Wheel Bearing Greasing & Torquing

Post by paul 300358 »

Having worked in vehicle product development in the 70's, I can tell you now that many of the figures are just what felt right for the bloke tightening the nut on the day someone was documenting the assembly. Often things were based on someone saying, "what if we did this" or " just nip it up a bit more and it will be fine". The size and tensile strength of bolts was often based on what was available in the production bins at the time of product development.
In other words, the bloke assembling the midget probably decided to take it to the next castellation rather than back it off, 50 years later it's written so it must be right. It was probably worse in the 50's and 60's.
Interestingly, my new hub has just arrived from the MG centre in Wales. The land between the bearing faces in the centre of the hub is 1.506 inch, my spare spacer is 1.501 inch long. When checking the bearings with a lightbox and straight edge the appear to be parallel. So there is 0.005 inch to take up the slack.
les
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Re: Wheel Bearing Greasing & Torquing

Post by les »

I’m not in a position to dispute but I do find it incredible that an official specification was decided by an assembly bloke suggesting ‘that’ll be ok’ :o

paul 300358
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Re: Wheel Bearing Greasing & Torquing

Post by paul 300358 »

TVR used to admit that no two cars are the same, it all depends what was available at the time of assembly. I do think that things have changed for most manufactures as they require standardisation to reduce costs.
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