11 replies to this topic

[Flyby]

Have just finished swapping engins over in my Mini. When I bought the car I was told that the big end and clutch had gone, the car came with a spare engine from an F reg. Have fitted all in but not yet started but am having problems with the clutch. The pedal depresses with only the spring tension, the reservoir is full, I have undone the bleed nipple on the slave cylinder (non verto type) and when the pedal is depressed air can be heard escaping from the nipple but I cant get any fluid to draw through.

Any help woulfd be greatly apreciated.

Thanks Dan.

[mattvallins]

Are you sure its the NIPPLE thats leaking? Not the seals on the cylinder itself?
Try and get a new nipple from somewhere to check if its that thats knackered!

[Guess-Works.com]

Have you tried bleeding it through with either and eezebleed kit or with an assistant. if you press the pedal with the nipple open and then let it of still with the nipple open, then it's just going to suck air back in...

[jimbo_edmondo]

if you press the pedal with the nipple open and then let it of still with the nipple open, then it's just going to suck air back in...

EH? Really guessworks? I'm sure the whole idea of having the nipple is because it is a oneway valve to get air out of the system? Maybe you left out the bit where you say 'if the nipple is broken then...'

Or am i completely wrong?????

[mattvallins]

They aint 1-way valves as far as I know!
*is not guessworks, sorry*

[jimbo_edmondo]

So why when bleeding my system while depresing the clutch it draws more fluid in from the resovior? And not air, are you saying that to bleed the sytem properly after each press of the clutch i need to tighten the nipple and then de-press the clutch?

[Guess-Works.com]

When you press the pedal the piston in the master pushes fluid, which is already in the system this inturn pushes the slave. As the piston is raised, fluid from the bottom of the master cylinder is drawn in to fill the void. When the pedal is released the piston comes down the fluid in the void is pushed back by the pressure in the slave. If the bleed valve is open when you push the pedal, then there is no pressure retained in the slave, and hence fluid is pulled past the piston in the master to replace, but if the bleed vale is still open, air will be drawn in through the bleed valve as that's takes less effort than pushing fluid past the master piston...

To watch this in action, put a length of clear tube ( about a foot or so ) on the end of the bleed nipple and open it. you will see when you press the pedal, the fluid travels up the tube, release ( with nipple open ) the fluid dissapears back into the slave..

Ezebleed kits have a one-way valve on the end of the tube to prevent this from happening.

[marc]

As guessworks says.

I have to do this at work, once the pedal is down close the nipple, release the pedal and repeat. It may take a few pumps before the fluid starts to flow.

[jimbo_edmondo]

Oh ok then my mistake, learn something new everyday! lol

[TimS]

i hope uv not tryed bleeding your brakes you way jimbo, if so rnt they incredibly spongy?

[jimbo_edmondo]

Not yet flappy lol, but i'll remember this! Last time my bro gave me a hand to fit a wheel cylinder an i got him to do the dirty bit, i just pressed the pedal lol!!!!!

[Flyby]

Thanks guys, admittedly I was keeping the nipple open between strokes (im sure ive had that problem before :tongue: )

The Haynes didnt say to close the nipple after a depression but I can see the logic in it now, will try it in the morning and let you know how it went.

Dan.