Oil in brake drum

[rolldrum]

Hi, I've been getting oil in my rear brake drum. I have a R80G/s, 1983. I've tried new seals on the brake actuating shaft without success. I had the bevel box apart and seen I've got the one bush setup. I want to swop for the long tube, however I can't find one anywhere, Motoworks, Motobins, Bmw Motrrad say they're not being made any more. My local machinist says he can't make something with such a thin wall! Can anyone help, Where to buy one or recommendations on where to get one made.
Thanks in advance

 

[walkingpictures]

Could be well worth giving Mikeyboy of this parish a shout,he's a top bloke

Kimbo

 

[EPG_19]

Oiling brakes reduces drag, it's used in Moto 1 training

 

[mikeyboy]

Hi, I've been getting oil in my rear brake drum. I have a R80G/s, 1983. I've tried new seals on the brake actuating shaft without success. I had the bevel box apart and seen I've got the one bush setup. I want to swop for the long tube, however I can't find one anywhere, Motoworks, Motobins, Bmw Motrrad say they're not being made any more. My local machinist says he can't make something with such a thin wall! Can anyone help, Where to buy one or recommendations on where to get one made.
Thanks in advance

As you say,no longer available,
Iirc and will confirm later in the week,you can use a paralever one which is slightly longer but has the correct I’d/od and shorten it to correct length

 

[SteveHop]

Two of us reciently found and ordered the "tubes" from Germany using the BMW part number from real OEM , think they were about £17 each so we both ordered them.

Only problem was that when they arrived they were to small on the outside diameter and just fell through the hole , so they were no good -- shit happens.

Anyway we both fitted new "O" rings only this time 10mm id X 2.2mm wall in Nitrile.

Guess what - no oil . Fingers crossed.

Think if you can get the "tube" fix i would go for it as its a better long term solution.

 

[rolldrum]

Brilliant, thanks for the info, I've got one on order from BMW, so hopefully it'll be the right size.

 

[SteveHop]

Hope it is the right size.
When we enquired from BMW they told us that they were unavailable?

 

[Packer]

If you have oil getting into the drum check the oil in the drive shaft, you may find that there isn't much in there, it's all leaked into the final drive raising the level too far and causing it to leak into the brake. Mikeyboy sorted mine. I think that there is a better seal for the input shaft. Mine is an '83 R100.

 

[mikeyboy]

As you say,no longer available,
Iirc and will confirm later in the week,you can use a paralever one which is slightly longer but has the correct I’d/od and shorten it to correct length

Well the para tube fitted ok,
Needed to shorten it by 12mm
15.8 mm od

 

[SteveHop]

Well the para tube fitted ok,
Needed to shorten it by 12mm
15.8 mm od

I measured the OD on the tubes we have got , they are 15.75 mm dia so 0.05mm down (2 thou). But they both fell through ,hole was around 16mm dia on both my bike a 1982 g/s and Chriss's bike a 83 ST. So not sure about it. Still might come in handy sometime.

 

[mikeyboy]

I measured the OD on the tubes we have got , they are 15.75 mm dia so 0.05mm down (2 thou). But they both fell through ,hole was around 16mm dia on both my bike a 1982 g/s and Chriss's bike a 83 ST. So not sure about it. Still might come in handy sometime.

I’ll check the part no

 

[sidkn33]

Continuing this thread rather than starting another.
I have a persistent problem with oil leaking past the three times replaced (Motorworks) oem spec o-rings.
So, three times I've repeated the exercise in vain because after only a few miles the rear brake pads/bevel box housing has enough oil in it to basically reduce rear brake to nil.

One thing I'm thinking about is the rear drive oil, which being level with the bottom of the level plug and consequently, also means the bottom of the brake spindle is rotating in a small amount of oil. Obviously that's partly why the o rings are necessary.

Would reducing the amount of oil to just below the spindle so it is not sat in the oil at all, reduce the likelihood of oil travelling along and past the o-rings?

Otherwise, is retrofitting a solid tube/bush (not available from Motorworks now btw), the only sure way to fix this flawed design?

 

[sidkn33]

Continuing this thread rather than starting another.
I have a persistent problem with oil leaking past the three times replaced (Motorworks) oem spec o-rings.
So, three times I've repeated the exercise in vain because after only a few miles the rear brake pads/bevel box housing has enough oil in it to basically reduce rear brake to nil.

One thing I'm thinking about is the rear drive oil, which being level with the bottom of the level plug and consequently, also means the bottom of the brake spindle is rotating in a small amount of oil. Obviously that's partly why the o rings are necessary.

Would reducing the amount of oil to just below the spindle so it is not sat in the oil at all, reduce the likelihood of oil travelling along and past the o-rings?

Otherwise, is retrofitting a solid tube/bush (not available from Motorworks now btw), the only sure way to fix this flawed design?

9pm

 

[sidkn33]

This is a 1983 R80ST and I've found this on Motorworks

Rear brake cam spindle bush in final drive

Stainless steel

www.motorworks.co.uk

 

[theoneandonly]

what is stopping you from machining the holes you have, and making them bigger , so the tube isn't as thin ?

 

[mikeyboy]

We retro fit the tube to all g/s and st rear drives when rebuilding,
One thing to be aware of,
Year dependant,some drives have two brass bushes,
Some only have one fitted,this then necessitates some machining work.
Also the tube from MW is not a tight fit so some sealant or bearing fit will be required

 

[sidkn33]

Seems my thinking re oil level isn't completely off-piste

https://forum.boxerworks.com/viewtopic.php?t=11511

So, as I am 500 miles from home and would prefer to have a functioning rear brake for my ride back, I will drop the oil level to sit just below the cam and hope this stops the oil seepage.

On that subject, as the oem o-ring spec is clearly too small, what size up of o-rings might I try as a temporary measure?
It's hard to understand how
BMW concluded this design to be an impovement (to lubricate the cam with gear oil).