Clutch problem

[stevem]

Hi Guys. Help needed, RV8, LT77 gearbox, Hydrolic clutch convesion by Magnum, SD1 slave cyl. When i first try and engage gears i have to pump the pedal a few times, it then seems ok for a few mins, then i have to repeat the pumping again. I have bled the clutch and there is no sign of any air in the system. any pointers cheers Steve.. ps, all parts where new when fitted, and i have only been up and down the road in it, about quarter of a mile at most..

[Clive]

Hi Steve,
Make sure the bleed nipple on the slave cylinder is on the top. If not you will never get all the air out of it.

[stevem]

hi Clive. The bleed nipple is to the top, When engine is running there is a faint noise from the clutch, but when i press the clutch pedal down it goes quiet. Any ideas.

[Purple AK]

Steve. If you can pump the clutch up so that it disengages. You have one of three problems. Either you still have air in the system. The master cylinder needs to be a bigger bore. Or you have too much freeplay in the slave cylinder pushrod/ball pivot.

[Clive]

Originally Posted by stevem

hi Clive. The bleed nipple is to the top, When engine is running there is a faint noise from the clutch, but when i press the clutch pedal down it goes quiet. Any ideas.

Hi Steve,
The noise is probably the clutch release bearing. I remember this being an issue with the old BMC "A" series engine/gearbox. As long as it doesn't get too bad I would leave it well alone, but if you ever have to remove the gearbox change it as a matter of course as the cost of a new bearing is nothing compared with having to remove the box again.
As far as the operation of the clutch is concerned i would agree with Purple AK, but I still lean towards an air/bleeding problem. There have been several posts in the past, so I would do a "search" and see what you come up with. I have read of folk removing the slave cylinder, but keeping the hydraulics attached, and lifting it as high as possible and then bleeding it. (Watch you don't push the slave piston out though!)
Good luck anyway, and keep us posted.

[stevem]

Hi Chris.Idont think there is any air in the system, when i bleed it all i get is fluid. How do i go about checking the other two things you mentioned, Cheers Steve..

[stevem]

excuse me for being thick, but how much air needs to be in the system for it to affect the opperation of the clutch?

[dingocooke]

I had a MG Midget clutch behave like this many years ago, and I ended up taking the slave cylinder off the bell housing and tilting it so the nipple end was exagerated higest end, then bleeding again; about 5 or 6 small bubbles popped out and all was fine; but not before Id already pumped about 2 pints of fluid through the blessed thing!!

Definately sounds like air to me

[stevee8]

Steve,
It sounds like air. Using pedal strokes at varying speeds can shift stubborn air when bleeding.

When you close the bleed nipple is the clutch pedal down or up?
It is possible to bleed these systems and then get air drawn back in via the nipple threads when the pedal is released. To avoid this, either get an assistant to hold the pedal down while you tighten the nipple or get them to slowly press the pedal through a full stroke while you tighten the nipple.

[stevem]

Hi. Ive just been in the garage and removed the slave cyl from the bell housing. Just waiting for the wife to get in so she can pump the pedal while i try and get any air out. Will let you know what happens. Cheers Steve.