Clutch Bleeding

[WoodleySaint]

Hi,

I consider my self a reasonably competant DIY mechanic but I'm completely lost as to why I cannot get my clutch to bleed properly.

I bought the car a month or so back and the clutch has been pretty heavy so I decided to replace both slave and master cylinders with ones from the local scrappy. (The clutch on the scrap car was much nicer to operate.)

I refitted the replacement components but try as I might I cannot get it to bleed properly, I had a one man bleed kit which I guessed must be faulty so I bought another with the same outcome.

With it not working correctly I decided to revert back to the old components and I can't get that to bleed properly either. I'm sure the unions are tightened sufficiently. When attempting to bleed the system the clutch is very light and feels the same when the bleed nipple if tightened.

Any advice would be very gratefully received, I've spent the whole afternoon on this and I'm massively frustrated.

Cheers Mark

[gazza1286]

The remaining air in the system is likely to be trapped in the slave cylinder. I would suggest either:

(i) as you bleed make sure the slave piston is in the 'fully closed' position. or

(ii) buy/borrow a vacuum pump and draw the clutch fluid through the system. Air bubbles are expelled more efficiently this way.

[Q.S.]

Hi,

I consider my self a reasonably competant DIY mechanic but I'm completely lost as to why I cannot get my clutch to bleed properly.

I bought the car a month or so back and the clutch has been pretty heavy so I decided to replace both slave and master cylinders with ones from the local scrappy. (The clutch on the scrap car was much nicer to operate.)

I refitted the replacement components but try as I might I cannot get it to bleed properly, I had a one man bleed kit which I guessed must be faulty so I bought another with the same outcome.

With it not working correctly I decided to revert back to the old components and I can't get that to bleed properly either. I'm sure the unions are tightened sufficiently. When attempting to bleed the system the clutch is very light and feels the same when the bleed nipple if tightened.

Any advice would be very gratefully received, I've spent the whole afternoon on this and I'm massively frustrated.

Cheers Mark

Get an assistant to help you and after every pedal stroke tighten the bleed nipple before releasing the pedal. Allow a little time for the master cylinder to recharge, open the bleed nipple and press the pedal to the floor again and hold whilst the bleed nipple is retightened. continue till all air is removed.

If you still have no joy with this method, you may need to use a pressure bleeder.

If you have no joy with the pressure bleeder, it may need to be 'reverse bled' with the pressure bleeder.

Hopefully the first method will do the trick.

[WoodleySaint]

Thanks guys, I'll let you know how I get on.

Cheers Mark

[WoodleySaint]

Well I've finally got it bled!!

No luck with doing it the conventional way or fully closing the slave. I bought a hand held vacuum pump connectng it up and it still wouldn't draw the fluid through. So I connected it up directly to the master cylinder and still no fluid. Took apart the old cylinder to better understand what was going on.....

The feed to the master is through a pin hole sized orifice. With the push rod connected to the clutch pedal the seal was masking the pin hole so no fluid! As soon as I disconnected the push rod fluid began to flow.

Hope this is useful to others and thanks for the advice.

[Q.S.]

Well I've finally got it bled!!

No luck with doing it the conventional way or fully closing the slave. I bought a hand held vacuum pump connectng it up and it still wouldn't draw the fluid through. So I connected it up directly to the master cylinder and still no fluid. Took apart the old cylinder to better understand what was going on.....

The feed to the master is through a pin hole sized orifice. With the push rod connected to the clutch pedal the seal was masking the pin hole so no fluid! As soon as I disconnected the push rod fluid began to flow.

Hope this is useful to others and thanks for the advice.

Is the pushrod length adjustable? If so, it's probably adjusted too long and not allowing the piston to return fully. There should be a small amount of play at the pedal with the adjustment correct.

[WoodleySaint]

Well I've finally got it bled!!

No luck with doing it the conventional way or fully closing the slave. I bought a hand held vacuum pump connectng it up and it still wouldn't draw the fluid through. So I connected it up directly to the master cylinder and still no fluid. Took apart the old cylinder to better understand what was going on.....

The feed to the master is through a pin hole sized orifice. With the push rod connected to the clutch pedal the seal was masking the pin hole so no fluid! As soon as I disconnected the push rod fluid began to flow.

Hope this is useful to others and thanks for the advice.

Is the pushrod length adjustable? If so, it's probably adjusted too long and not allowing the piston to return fully. There should be a small amount of play at the pedal with the adjustment correct.

Yes, the pushrod length is adjustable and is now set to the correct length so the specified pedal free play and master cylinder play are within tolerance. Thanks again.