R80/7 Final Drive Breather

[jackonz]

Hi, do any of you know how the get the breather out of the top of the final drive on my 1978 R80, I know that from 1980 on they are a screw in type but mine looks like it may be a press in item, as I know if they block up they can cause leaks am keen to make sure its clean and also its a bit rusty so would love to deal to that as well.

Thanks in anticipation.

[Kurt in S.A.]

I believe it is interference fit. I suppose one could remove the fill plug and find a way to pressurize the interior of the final drive and see if you hear any air coming out of the breather. Not too much pressure in order to cause problems. It appears to be #5 on this diagram:

https://www.realoem.com/bmw/enUS/showpa ... Id=33_0618

Kurt in S.A.

[jackonz]

Hi Kurt, yes you are correct it is #5 and I have done some searching on the net and you can purchase replacements and a Stainless Steel item is also available, so there must be a way of getting it out but it has me stumped at the moment, I really don't like rusty parts on my bikes.

[SteveD]

Maybe heat around it and try to pull it out?

[gspd]

My advice: If there are no seals leaking, leave it alone.
These breathers are usually problem free for the life of the bike unless exposed to EXTREMELY muddy off-road conditions over very long periods of time. I doubt you'll be able to remove it without wrecking it so I wouldn't recommend trying unless you have a new one in stock. I also would highly recommend AGAINST pressurizing the rear drive with compressed air to test it, you could damage or blow out a seal.
If you really are that concerned that it may be blocked leave your final drive unit upside down on your workbench overnight. Oil leaking out from the breather will prove to you that it's not blocked.
As far as rust goes, if it's just cosmetics you're worried about, clean it with steel wool and paint it with aluminum paint without removing it.
This free advice is worth every penny you are paying for it.

[Rob Frankham]

I believe it ios an interference fit and the only practical way to remove it without damage would be to dismantle the drive and drive it out from inside. I would go with (or rather have gone with) the idea of cleaning it up and applying a paint finish. Even if you have to do it every coule of years, it'll still be a lot less bother than replacing it.

Rob

[jackonz]

Thank you all, one thing I would never do is pressurize it with compressed air, what I will try is take the filler plug out (no oil in it at the moment) and using a plastic tube blow through it to be sure it is in fact clear.
What I did find blocked was the tell tail drilling for the seal on the output side, carefully pushing a thin stand of copper wire through cleared it.

[Kurt in S.A.]

I would never have put compressed air into the final drive. I was thinking, but didn't write it, to put a piece of tygon tubing that filled the hole and blow with my mouth to detect any leaking air. Simple enough.

Kurt in S.A.

[barryh]

I once tried getting the breather out of mine and gave up before I broke the cap off the tube as was sure to happen had I persisted. Haven't felt the need to trouble it again.

[mkj]

I have had no trouble removing the breather on the final drive on my R80/7, I simply drifted it out it was very easy. I had a lot more trouble removing the filler plug as the allen socket was rounded off, I eventually had to weld an allen key into the space.