Bleedin' Clutch!!!

topcatcustom · Post by **topcatcustom** » Wed May 12, 2010 7:33 pm

Hi guys, really want to MOT the car tomorrow but cant get the damned clutch to work. The clutch itself is ok with the push rod sticking out of the bellhousing by the right amount (1/2"), I have a new slave cylinder, new pipe and got another master cylinder to make sure its not that. I know this one works as I took it off a disco yesterday!

Today I re-drilled the pivot point further down the clutch pedal to give it more travel, we put an air bleeder thing on the master cylinder which forced loads of fluid and I think all the air out the bleed on the slave, but when we lock it off there is still nothing on the pedal!

It's driving me nuts, all new stuff and about 25-30mm of travel on the master cylinder but nothing at all

How can the bit that is stopping me getting on the road be the clutch on this big project!

stevieturbo · Post by **stevieturbo** » Wed May 12, 2010 8:27 pm

Is the master mounted correctly, and does the pedal return fully ( ie, actuating arm of the master )

And is the master actually ok ?

topcatcustom · Post by **topcatcustom** » Wed May 12, 2010 8:37 pm

Hi Stevie, the master is mounted fine, pedal returns to at least within a couple of mm of piston stop I'd say from when I put the pin in. It's the second master I've tried and this one came out of a disco that has only just had the engine removed, was still full of fluid as was the pipe so I have no reason to believe it is faulty...

stevieturbo · Post by **stevieturbo** » Wed May 12, 2010 8:56 pm

But is it mounted in the same orientation as the original car ?

And is the nipple on the slave at the top ?

All items need to be mounted correctly in terms of where air might collect, so that it can be bled out.

In my own car...because of how my master is mounted, I have to remove it to bleed it, and hold it in the correct orientation.

ged · Post by **ged** » Wed May 12, 2010 8:57 pm

Tom, it's not the clutch plate stuck to the flywheel is it?

topcatcustom · Post by **topcatcustom** » Wed May 12, 2010 9:20 pm

Hi Ged, cant get any pressure there to check, and the master is mounted exactly the same as in a disco. The slave does have the bleed nipple underneath the feed (

I know) but my Landy has exactly the same slave in exactly the same orientation and works perfectly- I have had to bleed it at least 3 times in the past due to having it out etc. That was the only other thing I could think of- unfortunately for me its a complete bugger to get to from any angle but I might have to try and turn it round somehow.

stevieturbo · Post by **stevieturbo** » Wed May 12, 2010 9:24 pm

just because the feed appears to enter above the nipple..doesnt mean its wrong.

The nipple just needs to vent teh top of the actual slave bore.

topcatcustom · Post by **topcatcustom** » Wed May 12, 2010 9:44 pm

This is like the one I am using, as mentioned- bleed nipple at the bottom just like my landy and works fine in that.

http://www.island-4x4.co.uk/images/CLUT ... R%20591231

This thing is a mystery and doing my head in, what can go wrong with 2 cylinders with a bit of pipe in the middle?!!!

stevieturbo · Post by **stevieturbo** » Wed May 12, 2010 10:06 pm

link no work.

Although usually airlock is the culprit.

So does the slave move at all ? Is there any response at the slave from pedal movement ?

From dry, can fluid gravity feed from reservoir, straight through to the slave nipple ok ?

Have you tried bleeding in reverse ? ie, pump fluid into the nipple ?

Tried pressure bleeding from reservoir to slave nipple ?

Can you clamp off the line to the slave, and see if the pedal is rock solid ? It should be if there is no air in the master.

Likewise pressing the slave rod with the line clamped.

ged · Post by **ged** » Wed May 12, 2010 10:45 pm

Tom, Turn your slave cylinder over so that the bleed valve is at the top & then re-bleed your system.

bones · Post by **bones** » Thu May 13, 2010 7:21 am

not sure if this helps, .

rich

topcatcustom · Post by **topcatcustom** » Thu May 13, 2010 8:52 am

I'm going to get an oil can and use it to pump fluid through the bleed nipple and up the line to the master, this should guarentee there is no air in the system, will also check the return position of the piston in the master cylinder.

Is it most important that the master cylinder piston returns as far as it will physically go when your foot comes off the pedal? It may be a couple of mm shy as it stands..

ChrisJC · Post by **ChrisJC** » Thu May 13, 2010 9:52 am

topcatproduction wrote:Is it most important that the master cylinder piston returns as far as it will physically go when your foot comes off the pedal? It may be a couple of mm shy as it stands..

Yes, because that's the point that new fluid is allowed into the system from the reservoir, and any excess pressure that has built up due to fluid expansion etc is allowed back into the reservoir. You really want a touch of free play in the linkage to be 100% sure.

Chris.

stevieturbo · Post by **stevieturbo** » Thu May 13, 2010 5:34 pm

Do the tests I told you to establish where the air is.

topcatcustom · Post by **topcatcustom** » Sat May 15, 2010 5:41 pm

Today- first checked the pedal-master position and it was actually under-adjusted by only about 1mm or so. Adjusted it slightly so it was about 1mm over.

Secondly I cleaned and filled an oil can with clutch fluid, fitted a snug clear pipe onto it and the slave bleed nipple and forced fluid up through the system a couple of times, few small bubbles but not a massive amount. After this there was/is some feel on the pedal but quite near the bottom and not exactly what you'd call sharp or positive!

Confident that there is no air in the system now, so I think I should unbolt the slave cylinder and look in the gap to see how much travel there is- maybe the clutch push rod needs extending a bit or something?

Can anyone confirm how far it should protrude from (flush with) the bellhousing? I was advised about 1/2" which it was when I set it up. The only other thing I can think of is maybe I need to move the pivot again on the pedal to give more travel on the master, though it cant be far out now so doubt it would make a massive difference.

Getting closer now- but not good enough to drive on yet