Loss of clutch fluid

AustinW

AustinW

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I am not sure I want to know, but what would cause the clutch fluid level to drop in the master cylinder? A leak, obviously, but where and the fix? There is no oil leaking from anywhere I can see.

I topped it up with some generic mineral hydraulic oil specified for mountain bike brakes - £6.95 from the local Car Care for about enough for 20x top ups.

2011 GSA with 61,000 miles. Clutch operates just fine.
 
No logical reason comes to mind so I'd say you have a leak. If you can't see where it is leaking......I'd pull the slave cylinder off and check it.

Hold the leaver in over night would check it
 
Mine leaked from the slave cylinder bleed nipple. The oil is so clean it didn't show on the swing arm, until I wiped a finger over it.
 
NZRalphy said:
No logical reason comes to mind so I'd say you have a leak. If you can't see where it is leaking......I'd pull the slave cylinder off and check it.

Hold the leaver in over night would check it
Click to expand...

Bendy toy said:
Mine leaked from the slave cylinder bleed nipple. The oil is so clean it didn't show on the swing arm, until I wiped a finger over it.
Click to expand...

I will wrap the slave cylinder in some paper towel and tie the clutch back and see what happens then. If its just the slightest of weep I reckon I will leave alone for now as I am building up for a bit of rear end attention (:eek:): the FD oil gets polluted, and I am pretty sure the bushes and bearings in the swing arm and associated pivots needing attention before too long. With all that out the way getting at and servicing the slave cylinder has got to be easier.
 
It could be an internal slave cylinder leak, you don't want mineral clutch fluid on your clutch disk. The clutch pushrod has a felt to soak up any tiny weeping but a leak is a different matter. I would remove the slave cylinder and check for seal leakage, a new clutch costs £400+ in parts alone!
 
I believe the old VW air-cooled boxer clutch plate will fit but that's another story.

The slave is easy to remove and costs about £80 to replace.

If the FD pool is getting sludgy you may have some failing bearings that have dumped their grease into the oil. Talk to MikeyBoy of Overland and Classic.

Mike did mine (FD and pivot) at 50K miles when the wheel bearing started to leak. He said it was all "ready". I had the rear subframe and lots of other stuff powder coated while I waited.
 
Bendy toy said:
Slave cylinder on eBay
http://www.ebay.co.uk/itm/BMW-R1200...726206?hash=item3608ca8d7e:g:y1oAAMXQVERS57Cb
Click to expand...

That was good, I tried a cheeky offer of £30 and they accepted it. :D Surely a bargain. Now, I just need to get the old one off sometime in the next week or so.

I assume its just a case of remove anything that impedes on access (anything?), undo the hose at the banjo, undo the two mounting bolts and remove. Replacement is the the reverse plus a bleed of the system (backfill, then bleed??)
 
Swapped the slave cylinder today. :D Bendy you are right - a fiddly job, but doable with a flexi driver that takes an T30 bit for the right side screw - off was OK, but back on took ages. The only thing else I removed was the silencer, but the rear shock off would make it a V easy job.

On reassembly I tried back filling with a 100ml syringe filled with some bicycle mineral hydraulic oil (£6.99) but still got loads of air in it so resorted to traditional bleeding methods and all seems OK. (I roped the wife in to pull in the clutch lever and top up the reservoir. She was as happy as anything helping me and getting hands oily and dirty while giggling at every "....and in.....and out...and in....and...."). I annealed the sealing washers on the banjo as I didn't have any the right size and nor did the local car-care shop.

The secondhand slave was the older model - it is missing a black sort of retaining/centring washer behind the circlip. I assume this was a design improvement on later models from 2009 (mine is 2011) and seems to keep the cylinder in place better and I think crap out too. The parts finder fiches say they are retrospectively compatible. Anyway its on the bike with the clutch lever strapped in and some paper towels under the master and slave cylinders to look for any leaks overnight.:thumb
 
Have the exact same fault. Missing fluid from reservoir, no leaks evident. Slave cylinder was replaced last year in May by BMW under extended warranty. Took it to them today and its booked in for Tuesday, so they can fiddle and fix. Score -I hope..
 
Well apparently BMW think that mine isn't leaking and the official explanation is that over time the air that was in the fluid comes to the surface and thats why I now see a 8mm gap between the fluid and the bottom rim of the lid....mm ok..well at least they checked.
 
I tried the syringe method from the slave cylinder bleed nipple but still struggled. I suspect air gets trapped inside the slave cylinder.
 
Bleed it as well as you can then pull the lever to the bars cable tie the lever in the pulled position and let it sit over night. If its like most other brake/clutch set ups the
air will rise to the top and come out in the reservoir.
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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