Hydraulic clutch issue on 091 gearbox (can't disengage)

[MiniRichard]

Hi all,
The Pinto powered van I bought last year always had something dodgy going on with the clutch - last year the clutch pedal occasionally went to the floor and wouldn't return, but lifting it up again resolved it - so for a while I just made sure never to press the clutch beyond about half way and all was good.
On the way back from camperjam the other week it was getting worse and worse and started to really judder when setting off. After getting home I noticed the reservoir was empty so thought I'd just bleed it for now as we were supposed to be going out again - got the mrs to push the clutch pedal and saw clutch fluid spraying out of the seal on the slave.

Went to repair/replace it but it turned out to be US sourced "Jamar" slave with an 8 week lead time - phoned around for an EMPI slave instead but the same story, so decided to just use a similar one from Wilwood via Rally Design.

Got that fitted and bleeding it was a total pain - the master (with no brand name or markings of any kind) was mounted upside down, so the reservoir and hydraulic line both connected from the bottom - assuming this was the issue since it was impossible to get the air out I unbolted it and turned it the right way to get it bled, then tried to fashion a bracket to hold it the right way up. Once this was done though it there just wasn't enough travel on the slave (only about 1/2") - this was down to 2 factors - the new slave was a larger bore (22mm) than the original (17mm), and the master now had to sit at a different angle to its original location as it fouled the floor, meaning the movement at the clevis now had a reduced effect on the master cylinder stroke.

Next I replaced the master cylinder - as I had no idea what bore the current one was, I went for a 25mm bore master, as with its 28mm stroke (which seems roughly equal to the travel of the clutch pedal at the clevis) this should. in theory, allow for the full travel of the wilwood slave which has 35mm stroke.

With the new master its now nice and easy to bleed, but the pedal will only go down about half way and no further and it doesn't disengage. If I disconnect it from the clutch arm on the gearbox or open the bleed valve on the slave I get full travel at the pedal, so I know the pedal / master setup allows is fine and, near as damn it, results in full travel of the master cylinder push rod.

Is it possible I'm just really unlucky and the clutch itself has actually failed?

Any one know what sort of travel I should get at the clutch arm on the gearbox - I'm assuming it should be around 1" at the point where the cable used to attach, since this is what the travel on the pedal end seems to be?

Thanks in advance guys, and sorry for the long post!

Rich

[MiniRichard]

Thought I'd follow up on this!
The inability to disengage the clutch turned out to be a combination of things - mostly the makeshift master cylinder bracket I'd made was flexing too much, but combined with how much pedal effort was required to actually disengage the clutch.
With a bit more strengthening added to the mount, the clutch now worked - but was VERY hard work!

I then replaced the 75mm clutch arm with a 100mm version and its now miles better, so I've now got:

Wilwood 22mm bore Pull Type Slave Cylinder:
http://www.rallydesign.co.uk/product_info.php?products_id=4080

Tilton 1" Bore Master Cylinder
http://www.demon-tweeks.co.uk/motorsport/brake-master-cylinders-reservoirs/tilton-75-series-master-cylinder-kit

100mm Clutch arm on the gearbox

The only slight issue is that to get the best alignment of the master to the original clevis on the pedal I need raise the master up about 1" through the floor, so I think I'll hide that under a "foot rest" next to the clutch pedal!

[steamo]

Nice work, glad you got it sorted. Hows the bus running now, on the road? Be good to see a bit more info about another pinto bus just to see how someone else has tackled it.

Mines going well now just need to fit a heater so its a bit more pleasant to use over the winter