90 CLUTCH(ing at straws).. Problem.

Removing the lid of the cylinder box shows no problems with the new master cylinder. Will try removing and replacing the slave cylinder and if that doesn't work I expect I'm into mega-£ and taking out the engine or the gearbox? :o(

If you are losing fluid do not worry about removing engine or gearbox.

Whatever your fluid loss problems, pedal should always return - pedal return spring missing? If the spring was missing when you bled the system it is probable that it was never properly bled.

Twas Sat, 16 Oct 2004 12:55:04 +0100 when "McBad" put finger to keyboard producing:

I once had the rod thingy that conects between the slave and the clutch thing break away from the thingy, the symptom was the clutch pedal locked hard in the up position so a mechanical failure beyond the slave seems to be ruled out in your case.

will the pedal still move up and down? if so then try the bleed nipple on the slave, if nothing there disconnect the pipe on the master and see if it pumps fluid from there.

if the pedal is doing something else then disconnect the pipe from the master and see if the pedal will pump up and down, this will point you towards the slave as the problem (a doddle to replace, be sure the exhaust is cool though). if the pedal isn't playing with the pipe off the master then I suspect the master has failed.

I've heard alot of tales of sudden failures of replacement masters, mine (replaced a month or 2 ago is fine) most people talk of metal swarf within the master shredding the seals.

I hope this all helps a little.

Regards. Mark.(AKA, Mr.Nice.)

There should be a quite strong return spring in the clutch master cylinder, strong enough to return the clutch pedal anyway, I'de check there first.

Peter.

Twas Sat, 16 Oct 2004 14:35:20 +0100 when "Peter Seddon" put finger to keyboard producing:

that is a damn good point there.

Regards. Mark.(AKA, Mr.Nice.)

Just had another look at the manual for a disco and it shows a return spring on the pedal as well so there should be no reason why the pedal will n ot return. Uless the master cylinder is also goosed.

Peter.

On or around Sat, 16 Oct 2004 15:22:10 +0100, "Peter Seddon" enlightened us thusly:

If the pedal doesn't return fully and thus the master cylinder doesn't return fully home, it'll not let more fluid in from the reservoir, either - it only does that bit at the very end of the travel at the "top" end. This can also occur if you adjust the pushrod too tight.

Twas Sat, 16 Oct 2004 15:49:38 +0100 when Austin Shackles put finger to keyboard producing:

out of interest, what happens if the pushrod is adjusted too loose?

Regards. Mark.(AKA, Mr.Nice.)

On or around Sat, 16 Oct 2004 19:22:12 +0100, Mr.Nice. enlightened us thusly:

not enough movement in the pedal. The pushrod, as I expect you know, or maybe not, it not positively attached to the piston, it just literally pushes it. it's held in a trunnion in the top end of the pedal by 2 nuts. If too tight (i.e. pushrod effectively too long) then the pedal comes up against a stop somewhere and maintains pressure on the piston, keeping it from returning fully out. if the rod is too short, then the pedal will be lower in the car and you may not have enough travel properly to operate the clutch before it hits the floor. Also your clutch bite point will be lower.

Thank you to everyone who has replied. I'm going out to have another look at it now - didn't do anything further yesterday as I couldn't get a spare slave in the afternoon.

I'll start with the spring which is on the pedal somewhere; it's a sort of rat-trap type spring around the pedal rather than a long spring between the pedal and one of the six pedal box mounting bolts. Can't really see what this spring does; doesn't the pressure from the clutch itself return via the slave and hydraulic fluid to push the pedal back up? At the moment the pedal seems to be stable in either the bottom position (ie it will sit on the floor) or it can be lifted by hand and it will stay stable in the up position, it just won't return on it's on and there is no resistance under your foot when you press down. However, the spring has worked successfully for two weeks and even if it had broken why am I not feeling any resistance from the clutch via pedal when I put my foot on it?

I'm pretty confident that the pedal and the push rod are properly adjusted as to 114mm from the floor in the up position and 1.5mm of play in the push rod. As the pedal is lifted with the cap off the fluid reservoir you can see a 'flicker' in the brake fluid level as the pedal reaches the top of its travel, suggesting the fluid is available to the system from the reservoir.

I'll go and have a poke round now and report back, I'll be interested to see if the fluid level in the reservoir has dropped over night... Really annoying watching all the other land rovers passing the bottom of the street on the way to the RTV I was meant to be at today!

Cheers,

M.

Reservoir fluid level had dropped about an inch over-night. Back of the pedal was damp but can't tell if this is a leak or if I spilled some fluid yesterday when I was filling the reservoir, angle of the bonnet makes it very difficult to pour accurately.

The spring on the pedal only seems to come into play on the last third of the movement on the up stroke; if you lift the pedal from the floor when you get two thirds of the way up to normal height the spring takes over and forces it the last third. I guess this is to ensure that the pedal comes up far enough for the reservoir on the master cylinder to open to the master cylinder piston bore.

I took the pipe to the slave off the master cylinder at the 13mm nut. As I removed the pipe air bubbles appeared at the joint from the master cylinder and the fluid level in the reservoir dropped. Depressing the clutch pedal then shot a very healthy dose of brake fluid from the open joint, suggesting the master cylinder is ok. But how is air getting into the master cylinder? It was bled to death yesterday morning???

FIXED IT (but for how long?)

Bled the system again and eventually got a hard and fully returning pedal. Certainly confirms that it is not the clutch release bearing, lever or clutch return spring that is at fault. Still very puzzled as to how an air lock got into the master cylinder overnight and will be keen to find out if pressure is maintained until tomorrow morning. I wonder if there is a slow air leak into the master cylinder past the piston...

Cheers,

"McBad" wrote in news:qsOdnWxbR8FNwe snipped-for-privacy@brightview.com:

Suggest you check the joints and connections of the pipe.

I had an intermittent problem with one of my Peugeot 504's. It was driving me nuts! The clutch would fail at the most inconvenient time at a location miles from anywhere.

Turned out to be a connection. Sucking air. I fitted an "O" ring inside the connector and the problem was solved. Then I sold the truck (stupid me!) and it has run perfectly ever since!

Derry

i take it you lost the fluid out of the master cylinder ? , but it isnt leaking out of any pipes and you dont see any damp patches anywhere .

if this is so then its the slave cylinder thats the problem and youll find that the fluid has leaked out of the slave cyl into the bellhousing .

the slave cyl only has one piston ring in it and these do fail after a while.

it was more prevalent on older 90s which had the slave cylinder right next to exhaust downpipe and would get fairly hot in summer .

youll notice that the r380 box doesnt have slave cyl close to exhaust pipe .

on every range rover classic and landy 90 i have had, the slave cylinder has failed at least twice in a handfull of years .

its cheap to buy a slave cyl repair kit and fix youreself if you have garage eqpt as below ..

to do it comprehensively you need 1" a "delapeena" flexhone to hone the bore of the slave cyl , with an electric drill moving it in and out rapidly so as to get 45degree" lapping marks ". this is to "clean " the bore of slave cyl and not to make it any bigger .

if you cant hone it out then you can just fit a repair kit of seals if youre on a tight budget , but for price of a new slave cyl most people would opt for a complete slave cyl unit .

when the slave cyls go they tend to leak only a little bit over a period of time and you dont notice it until all the fluid has gone from master cyl and down the hyd line .

if you lost all fluid and cant get fluid to pump out of master cyl the easiest way to bleed the clutch cyls is by back bleeding from the slave cyl upwards .

fill master cyl first with brake fluid .

leave tube nut slack on hyd pipe off the master cyl , use a new "oil can " filled with brake fluid with rubber hose attatched to it and to bleed nipple on slave cyl . pump oil can and fill slave cyl/pipe until fluid comes out of pipe at slackened fitting on master cylinder , then tighten nut .

you should now be able to pump the clutch pedal and bleed out half pint or so of fluid and this should get rid of any air in system and job will be done .