Trying to bleed a new clutch on another project so I can get back to the cruiser, never had a problem bleeding a clutch before. It's an '89 BMW 535is, standard hydraulic clutch system, RHD means it has it's own resevoir not shared with brake system, for any one who knows these cars.
New clutch disc, pressure plate and throw out bearing and slave, all fit nicely. I have bled this thing with every method you could think of and still don't get clutch disengagement. Slave bleeder is on the bottom of the slave, and the fork is internal without any access ports to even fit a boroscope through to check function, so I've reverse bled it with an old oil can bottom to top to make sure there's no air in the slave. Clutch pedal feels perfect, exactly how it should be, doesn't get stuck to the floor, engagement nice and high up in the travel.
Still nothing, only leaves the master. Ordered a new one, but I want to understand what's failed either way. No fluid leaks at any hard lines, soft hoses, slave, master or reservoir, soft lines aren't bulging at all and look fine, no rust anywhere and I've checked every hard line is nipped up nicely. If I pump the clutch pedal 100+ times after any kind of bleed I still get air bubbles popping up in the reservoir consistently. Standard top to bottom bleed will take 500mL of fluid while still shooting out bubbles and then I give up.
Is it possible that the master is somehow drawing air through the pushrod end past the o ring on the piston and into the cylinder? When returning the pedal back up I can hear the faintest 'slurp' sound in the last ~5% of travel. I guess this could be the problem, but I imagined if that was the case it would also be leaking fluid into the cab.
New clutch disc, pressure plate and throw out bearing and slave, all fit nicely. I have bled this thing with every method you could think of and still don't get clutch disengagement. Slave bleeder is on the bottom of the slave, and the fork is internal without any access ports to even fit a boroscope through to check function, so I've reverse bled it with an old oil can bottom to top to make sure there's no air in the slave. Clutch pedal feels perfect, exactly how it should be, doesn't get stuck to the floor, engagement nice and high up in the travel.
Still nothing, only leaves the master. Ordered a new one, but I want to understand what's failed either way. No fluid leaks at any hard lines, soft hoses, slave, master or reservoir, soft lines aren't bulging at all and look fine, no rust anywhere and I've checked every hard line is nipped up nicely. If I pump the clutch pedal 100+ times after any kind of bleed I still get air bubbles popping up in the reservoir consistently. Standard top to bottom bleed will take 500mL of fluid while still shooting out bubbles and then I give up.
Is it possible that the master is somehow drawing air through the pushrod end past the o ring on the piston and into the cylinder? When returning the pedal back up I can hear the faintest 'slurp' sound in the last ~5% of travel. I guess this could be the problem, but I imagined if that was the case it would also be leaking fluid into the cab.