Clutch bleeding

[Keppelj]

A search on this forum yields quite a bit on clutch bleeding and I looked it over before starting, got a bit confused by what sounded like a couple of solutions, and then tried the job in the way which seemed easiest: unscrewing the grub screw and replacing it with BMW bleeder (part # 34 21 2 330 310) for the bleeding. The heavy foam sleeve around the bleeding housing needs to be rolled back at the hose end so a wrench can be gotten on its base so the grub screw can be removed. The screw was tight but no heat was a needed to remove it. However, the bleeder screw just barely gets into the female threads before it's stopped by the ball valve in the mechanism so that if you force at that point the aluminum housing threads may be stripped. Problem is that the point on the bleeder which would push on the ball release is too long by about 1/16 of an inch or so. Grinding that off allows the threads to get sufficient purchase in the housing to force the ball down to allow the hydraulic fluid out. I used a combination of Miti-Vac and clutch lever to flush the system with fresh oil after first drawing the old oil out of the reservoir with the vac and pouring in new. I'm left wondering how the BMW mechanics accomplish this with the bleeder valve as it is.

[CycleRob]

The bleeder screw you purchased is meant to replace the entire black painted Aluminum bleeder assembly. The dealer hooks that assembly up to their proprietary shop equipment and apparently the factory leaves it on the bike for them - - - it certainly serves no purpose for us owners. Disconnect it from the hose fitting and use your bleeder fitting. I put Moly grease on the male threads to prevent galling that can/would occur with the female Aluminum threads during the multiple loosen/tighten operations used in bleeding the rear brake. Be careful to not overtighten the bleeder between rear pedal pumps and on the final tightening as the grease can increase the actual torque by +30%.

[Boxer]

I feel the need to clarify something here for my buddy Cyclerob. Apparently, he's been staying up too late watching to the Democratic National Convention. In the first half of his post he is definitely referring to the clutch bleed grub screw and the adaptor which is purchased to replace the grub screw and make bleeding the clutch easier for us.

However, the second part of his message he switches to discussing the rear brake bleeding. Just ignore the part about the rear brake. He knew what he was saying. He just got the two mixed up.

Sorry Rob. I couldn't resist.

[Keppelj]

Ok, got it - maybe. With the aluminum bit unscrewed, is there a ball valve in the remaining piece so the BMW bleeder can be inserted and removed, the aluminum piece returned without leaving any air behind? Sounds like you leave the grub screw in place throughout this approach.

[CycleRob]

Boxer is absolutely right, the FoxNews channel coverage of the delusional DNC convention actually was on in the background. Charles Krauthammer's assessment of it was spot on. I also had "rear brake" on my mind from dealing (hands on in my garage) with rear master cylinder problems (cracked rubber piston) on CaptainCable's R850R. BTW, shame on BMW for offering NO INTERNAL REPLACEMENT PARTS for their master cylinders . . . only a $130 full replacement (on the R850R) . . . true even for my 2009 F800ST !!

About the clutch bleeding operation, Keppelj likely came across my post on it where it was mentioned to:
1--close bleeder.
2--squeeze and hold clutch lever to handlebar.
3--release bleeder quickly, pause 1 second then tighten.
4--release clutch lever, pump lever partially a few times to increase pressure building lever travel.
5--repeat 2--4 at least 10 times to "dilution purge" the old fluid in the slave cylinder.
5--be aware of the fluid level under the bellows in the reservoir !

Bleeding the slave without the sequenced "working" of the slave piston back-n-forth as above will not change ANY dirty old fluid in the slave.

[shards]

BTW, shame on BMW for offering NO INTERNAL REPLACEMENT PARTS for their master cylinders . . . only a $130 full replacement (on the R850R) . . . true even for my 2009 F800ST !!

I agree but...shame on Ducati (and any Brembo brake user) for being in the same situation. I am told this is a "Brembo Induced" policy, not the manufacturer, and is done, again so I am told, to stop home mechanics screwing up the re-fitting of brake components, causing a crash, and suing Brembo. All sounds a bit BS but, in our Nanny Sate, Lawyer Rich, society, it could be true.

[Keppelj]

Ok, thanks. I got fully clear fluid by my method above using the mini-vac, but I'll try the two person method, lever and bleeder valve. I wondered about the slave.