Bleeding a clutch
Discussion
Chaps, I would appreciate your help and advice.
I've replaced the slave cylinder and hard line due to a leak but I am really struggling to bleed it properly.
My method is (with assistant), depress clutch, open bleed valve, wait for bubbles to stop/piston to get pushed in by clutch actuation lever, close bleed valve, raise clutch. Rinse and repeat (ensuring reservoir doesn't run dry).
This seemed to be working well, but what seems to be happening now is that when I open the valve, mostly fluid is coming out but when the piston has been pushed in lots of little bubbles appear in the pipe attached to the bleed nipple. If left for a minute or so the bubbles slowly work their way down the tube (whether due gravity or pressure from the hydraulics). Bleed nipple is at the top of the slave cylinder. This has been the situation for the last 10-15 cycles of bleeding and I feel like I am just wasting brake fluid and not getting rid of any air. Either way, little or no air is coming out in the initial release of pressure when the bleed valve is opened.
Clutch is weighty but maybe spongy and clearly isn't disengaging the clutch as I can't select any gears with the engine running.
What am I doing wrong?
I've replaced the slave cylinder and hard line due to a leak but I am really struggling to bleed it properly.
My method is (with assistant), depress clutch, open bleed valve, wait for bubbles to stop/piston to get pushed in by clutch actuation lever, close bleed valve, raise clutch. Rinse and repeat (ensuring reservoir doesn't run dry).
This seemed to be working well, but what seems to be happening now is that when I open the valve, mostly fluid is coming out but when the piston has been pushed in lots of little bubbles appear in the pipe attached to the bleed nipple. If left for a minute or so the bubbles slowly work their way down the tube (whether due gravity or pressure from the hydraulics). Bleed nipple is at the top of the slave cylinder. This has been the situation for the last 10-15 cycles of bleeding and I feel like I am just wasting brake fluid and not getting rid of any air. Either way, little or no air is coming out in the initial release of pressure when the bleed valve is opened.
Clutch is weighty but maybe spongy and clearly isn't disengaging the clutch as I can't select any gears with the engine running.
What am I doing wrong?
pump several times, full pedal strokes.
hold down, release nipple until air/fluid is ejected and tighten
repeat as necessary
Often you need to pump the pedal a few times in between. Just doing repeated single strokes and bleed doesnt allow the fluid/air to settle really.
Although if you've driven the car in between bleedings, that should have pushed any remaining air to a place where it would bleed out next time you tried.
hold down, release nipple until air/fluid is ejected and tighten
repeat as necessary
Often you need to pump the pedal a few times in between. Just doing repeated single strokes and bleed doesnt allow the fluid/air to settle really.
Although if you've driven the car in between bleedings, that should have pushed any remaining air to a place where it would bleed out next time you tried.
What car? On sone BMW's and by extension I suppose other cars, the slave cylinder has to be removed from the gearbox & inverted before bleeding to ensure that air trapped in the cylinder can rise to the bleed nipple then pass out of the cylinder when the nipple is released. Might be best to google for others who've done the same on your car.
On our old Z3, I used a mastic gun frame to hold the slave cylinder piston in and inverted whilst pressure bleeding with a Gunson kit. It was spot on, but I nicked the idea of the Z3 forum, so there's usually someone brighter who's gone before & thought it through.
On our old Z3, I used a mastic gun frame to hold the slave cylinder piston in and inverted whilst pressure bleeding with a Gunson kit. It was spot on, but I nicked the idea of the Z3 forum, so there's usually someone brighter who's gone before & thought it through.
Know it's an old thread but Ive had a bit of trouble bleeding the clutch this week, with a long line with high points, everything I found online didn't work ( didn't try vacuum ) I found removing Union and placing the pipe in the full reservoir, removing the pin from the slave and pumping the arm drew out all the air, bleed as normal after of needed.
Hope this helps with any future problems.
Mgtf / mgf
Hope this helps with any future problems.
Mgtf / mgf
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