Final drive oil "mist"

[Spud]

Whilst getting some new tyres fitted and hence having the Rear wheel off, I noticed a "staining" of the lower half of the inside of my final drive. There has never been any appear on the wheels or seen obviously leaking from it. I've recently changed the final drive oil and there were no obvious bits of metal in the fluid or stuck to the plug.
There is just perceptible play at the wheel rim if you grab it and try and rock it, but I would estimate it to be fractions of a mm rather than anything else.
I've ordered a new oil seal, but not removed the old one as yet. I've researched on this and other forums about how to replace the outer bearing if required and thought I could manage that ok. But then as I read some more, I got myself rather confused about pre loads etc. (I'd figured out the pre load bits I thought, but then people started going on about pinion mesh etc and I got worried !!!)

SO, Is this a fairly simple DIY job as I first thought, and if the bearing looks ok when I remove the oil seal, do I just leave the bearing be?
Or, do I replace the bearing with the original shim? Do I need to measure the pre load, order a "correct shim to give between .05 and .10 of pre load?

Or is it all much more complex and should be left to an "expert" ?

Bike has 80,000 miles and as far as I know, this has never had a seal or a bearing in the past ......help !

 

[Nick591]

Bearings are a standard size to very precise tolerances. Shims are used to take account of slight machining dimensional variations in the casing and hub components to achieve the correct preload on the taper roller bearing. As long as you are not changing any of the casing parts you should be able to re-use the same shims with a new large bearing.

Sent from my SM-G920F using Tapatalk

 

[Spud]

Bearings are a standard size to very precise tolerances. Shims are used to take account of slight machining dimensional variations in the casing and hub components to achieve the correct preload on the taper roller bearing. As long as you are not changing any of the casing parts you should be able to re-use the same shims with a new large bearing.

Sent from my SM-G920F using Tapatalk

Thanks Nick. I'll pull the seal off and see how things look. But if I do need to do the bearing the makes me feel a lot happier ......

 

[Steptoe]

The "play" is most likely to be at the paralever bearings. Simply adjust the inner pivot to removed the play.

 

[Spud]

The "play" is most likely to be at the paralever bearings. Simply adjust the inner pivot to removed the play.

Thank you Steptoe, I was kinda hoping that's going to be the case.
The new seal won't arrive until the weekend so hopefully it'll all be ok by next week (fingers crossed !)

 

[shuck raider]

Noticed an oil mist on my final drive last summer when I arrived in Portsmouth from Holyhead having hammered down the M6 en route to Spain.

Wiped it off and kept an eye on it as I pootered around the Picos. Didn't re-appear

Then checked again having hammered up the M6 before boarding in Holyhead - mist again On the ferry, it occurred to me that the longish breather pipe in front of the final drive might be the culprit Re-routed it in Dublin and hammered up the M1 home and it hasn't appeared since. Mind you, haven't done much hammering since the trip so I'll continue to regard the rear end with deep suspicion

 

[fizzer]

that 30mm nut on the adjustable side of the paralever bearings bearing is really really tight if you have a blow lamp warm it up it will also soften the thread lock bmw put on at first build .the adjustable side pin should be torqued to about 10nm ,i just take it up and back it off a tad ,then retighten the 30mm nut really really tight again

 

[Spud]

Noticed an oil mist on my final drive last summer when I arrived in Portsmouth from Holyhead having hammered down the M6 en route to Spain.

Wiped it off and kept an eye on it as I pootered around the Picos. Didn't re-appear

Then checked again having hammered up the M6 before boarding in Holyhead - mist again On the ferry, it occurred to me that the longish breather pipe in front of the final drive might be the culprit Re-routed it in Dublin and hammered up the M1 home and it hasn't appeared since. Mind you, haven't done much hammering since the trip so I'll continue to regard the rear end with deep suspicion

I'll check that out but it definitely looks like it's coming from the seal.
You never know, I might get lucky !!

 

[Mzokk]

Mind you, haven't done much hammering since the trip so I'll continue to regard the rear end with deep suspicion

Hi Arthur great quote......innuendo bingo anyone.