Clutch fluid top up question

[Bones]

The cap says use mineral oil. Will a few drops of 3 in 1, cheap mineral lawnmower oil or semi synthetic engine oil do? I have got a weep on the lever/piston, about one drip per week so not worth fixing IMHO, just need a teaspoon of oil every 3 months.

 

[JJH]

No no no. Try it anyway. No don't. Might be interesting. Or try some mineral semi synthetic. If it was me I'd fix the leak. Or at least investagate it. JJH

 

[bigmadstu]

Best to get it fixed tbh, loosing a small amount is no big deal but if it can get out, then air can get in. That's not good.

 

[Bendy toy]

Citroen LHM hydraulic fluid is the same stuff but BMW charge 10x as much so theirs must be better oil.

Note. The clutch oil level rises as the clutch plate wears. I struggled to extract all air bubbles but gentle lever movement with the bars angled so the oil could escape gave me a less sloppy lever action. Maybe my master seals are failing but they looked ok when I opened it up so it's perhaps just a "feature" of the system. Also the cylinder was totally dry on the outside so I believe the seals are fine.

 

[Bones]

Thanks for the replies. I wil get around to fixing it properly as soon as I have time (could be a while).

This look like the best deal for the required liquid

http://www.emotorspares.co.uk/ecomm...Results.aspx&gclid=CKmY-e6T0swCFcrjGwodQYUCPw


BTW if anyone has a link for a seal kit. I have had a google around and can't find one. Motorworks don't seem to stock either

 

[Bendy toy]

BMW told me they only sell a complete master cylinder. £200 (ish) to your sir.

 

[Myke Rocks]

The cap says use mineral oil. Will a few drops of 3 in 1, oil do?

DO NOT USE. 3 in 1 oil is a vegetable oil, and if mixed with mineral oil, the result will turn to glue. I have seen the unfortunate results of such a mix in the past, both on pneumatic systems and in worm gearboxes.
Myke

 

[Bones]

The 3 in 1 option wasn't a serious suggestion Thanks though. I did read on another site that brake fluid with added castor oil will do the job? !?! (I won't be going down that route either)

If the only option is a new master cylinder I will live with the weep though! Must be fixable surely.

 

[Bendy toy]

The weeping seal is likely to pull in air. However a total strip down and clean might fix the issue.

Maybe someone in engineering or hydraulics components can find a source.

 

[roamer]

Lhm oil or vw green power steering oil is all mineral high quality capable of high temperatures, magura blood used in mountain bikes is the same stuff,
The rubber seal starts to lose its surface shape and leaves residue,
This is early warning, maybe you could find a seal , or s/ h master,
Roamer

 

[Bendy toy]

It's mineral oil so the seal wont be rubber but that doesn't stop it wearing.

It possible a brake cylinder seal would work and the system might of fine with silicone oil. It would have to be 100% cleaned out and silicone oil is vey searching for leaks.

 

[Bones]

I've covered 60K mainly commuting miles on the bike. Once in London you spend a lot of time on the clutch so it's no surprise it's wearing. The clutch action is normal so far. At the moment it's just a single drip of fluid landing on the tank once or twice a week but the weep can only get worse I guess.

 

[Bendy toy]

My annoying spell chaser (yet gain) seems to have reworded what I wanted to say.

I meant that converting it to silicone oil would allow you to use a brake system seal. As they are quite common you'll have more chance getting a part to fit.

The clutch master cylinder can be stripped like any other, so worth a look to see if there is dirt in in the sealing area.

If it all goes wrong you would then bite the bullet with a new master cylinder, but silicone oil wont harm the hose or slave cylinder.

 

[richtel]

I beleive Magura red is the latest stuff the BMW use after the change from the blue vitamol v10.