Clutch not disengaging - bled but struggling with settings

[HucklebuckRover]

It looks like I have some slack in the mechanism before it engages.

This looks off right?

https://www.dropbox.com/scl/fi/rka9vgz1hfopo5blb52oo/2024-07-27-16.25.32.mov?rlkey=mcx89qfpc10n5g9uzxzxz5eqr&dl=0

[HucklebuckRover]

I have the internal clutch withdrawal mechanism that operates on the rotating shaft. One thing I am seeing though is that it may work better with the 9.5" clutch and pressure place that has a flat and extended pushing surface that would give the flat surface of the style throwout bearing somewhere to push on more than the 9" pressure plate that's init now that has the three forks.

Could it be that your clutch fork pivot is worn? Check out Britannia LR restorations (https://britrest.com/product/super-duty-clutch-fork/) as he sells a fork with an reinforced pivot for the pushrod. Watch his video explanation.

[biffidum]

Could it be that your clutch fork pivot is worn? Check out Britannia LR restorations (https://britrest.com/product/super-duty-clutch-fork/) as he sells a fork with an reinforced pivot for the pushrod. Watch his video explanation.

[HucklebuckRover]

Checking back in to see if there are any other thoughts.

Bled the system again.

Checked the shaft pins.

I did notice a little freeplay in the release mechanism shaft when things were disconnected but guessing that's normal

Pedal should be ok -

slave rod has been extended a bit to try and make up for any wear or crap adjustments

Still nothin - it seems that the release bearing is being activated via the sight hole

Can still start in gear with the clutch down and not move until releasing the clutch

I feel like that would mean the issue is not internal right?

This is driving me nuts.

Thanks - Yeah I've gone through the green book settings and just can't seem to get it - I'll double check the pins. One thing that I keep getting turned around on is the master cylinder setting. Should I slack those off and set the pedal with the adjustment bolt in the end of the housing and then tighten the lockups on the master to suit?

If there was major internal clutch damage do you think it would still engage as it is releaseed when started in gear? I'm tempted to separate the engine and tranny again but thinking it may be a waste.


Yes for double clutch when I remember

[HucklebuckRover]

Thanks - Yeah I've gone through the green book settings and just can't seem to get it - I'll double check the pins. One thing that I keep getting turned around on is the master cylinder setting. Should I slack those off and set the pedal with the adjustment bolt in the end of the housing and then tighten the lockups on the master to suit?

If there was major internal clutch damage do you think it would still engage as it is releaseed when started in gear? I'm tempted to separate the engine and tranny again but thinking it may be a waste.


Yes for double clutch when I remember

Clutch adjustment on these things is basic in the sense that you turn the adjustment bolt on the upper housing until the clutch pedal has about 1/2" of free play (grab and wiggle). This way you know the release bearing is not engaged when the pedal is at rest (won't last long otherwise). If you can't change gears when running you need more throw - which tells me you have way too much free play in your pedal or you have air in your lines.

If your pedal has normal free play, you might have to push fluid through the lines (bung and a tiny bit of air pressure) if you are concerned about air.

I rerouted my clutch hard lines to go straight down to the slave with a couple of bends to accommodate engine vibration. It is far simpler to bleed as bubbles go straight up and out.

Are you double clutching?

[roverp480]

Check that neither of the cross pins in the coupling sleeve between the release bearing housing and the operating shaft where it passes through the rubber grommet, have not broken . Often one end can break vastly reducing the amount of available movement . Item 65 is the pin and 64 the coupling sleeve , This is a picture of an early s2A but the principal is the same and the pins now often have a head on one end and just one split pin the other, also the spring 68 was deleted later on. I have had this happen a couple of times over the years. The pin being in two pieces and still in situ, so not obvious it was broken .

[biffidum]

Clutch adjustment on these things is basic in the sense that you turn the adjustment bolt on the upper housing until the clutch pedal has about 1/2" of free play (grab and wiggle). This way you know the release bearing is not engaged when the pedal is at rest (won't last long otherwise). If you can't change gears when running you need more throw - which tells me you have way too much free play in your pedal or you have air in your lines.

If your pedal has normal free play, you might have to push fluid through the lines (bung and a tiny bit of air pressure) if you are concerned about air.

I rerouted my clutch hard lines to go straight down to the slave with a couple of bends to accommodate engine vibration. It is far simpler to bleed as bubbles go straight up and out.

Are you double clutching?

[HucklebuckRover]

Having this issue again - can start in gear and release the clutch to move but can't shift while running -

[jimrr]

i ran my clutch master cylinder low the other day. I filled it but what air in there is slow to work its way out but since it still works ok i'm not crawling in the snow and mud to deal with it occurs to me that if the pipe to the slave has ANY high spot in it, a air bubble in there may not be easy to flush out. the next time i'm under there i'll insure the pipe hasn't been altered (hit by tree limb etc) I also thought woring the clutch while on a steep hill (both directions) could help dislodge air. this may be worth a effort?

[jimrr]

i didn't read thru all this (again) but is the pedal firm? sometimes it's notoriously hard to get the air out. with hydrostatic the pedal will be firm from the top down, a most steady force to be applied, no soft then firm feelings. ?

[biffidum]

It could be that the pivot on your clutch fork has worn excessively. Some are plastic and very weak. You would have to look inside through a port or pull the transmission.

[roverp480]

A long shot but do you have a 9.5" Diaphragm spring clutch or a 9" coil spung one? I had your symptoms when my Diaphagm Spring mounting in the cover started breaking up, very difficult to see, but it meant when operating the pedal, although it reduced the pressure on the friction plate it didn't totally remove it. This meant on the move it was sufficient, but stationary it dragged too much.

[andrew]

my condolences but when stuff gets tight it's better to adjust schedults, kick back and really dig in ........... there IS A REASON, . as a professional engineer that often had to diagnose various systems (power, electrical, ac, water .......... )) i learned you can not accurately diagnose without understanding how it works. I know I know ........ I had to study book after book and it would eventually pay off, no one else figured it out, i would but it may take 2 days of intense scrutiny !!!
Good luck and don't let up !

This is from another forum, and a post from another user, but perhaps it's of use for you or someone in the future:

"The green Bible gives two methods to adjusting the slave pushrod. The 2 7/8 approach OR you can adjust the push rod so that (when the clutch is fully depressed) there is approximately 1/8 in (3mm) of clearance between the bottom of the piston and the circlip at the bottom of the cylinder.

The latter is a better way in my opinion - with different length push rods, clutch plate thicknesses, etc. It gives you a good starting point for the (remaining) life of the clutch plate and ensures the slave cylinder's piston never bottoms out at either end.

The volume of fluid (travel range) moved in the slave cylinder is determined by the master cylinder. All the push rod does is determine where, in the slave cylinder, that fixed travel range takes place. Ideally the bottom of the slave cylinder's piston (when clutch is fully depressed) is as close as possible to the bottom of the slave cylinder without bottoming out. As the clutch plate wears, the bottom of the slave's piston will get a little higher relative to the circlip."

[jimrr]

my condolences but when stuff gets tight it's better to adjust schedults, kick back and really dig in ........... there IS A REASON, . as a professional engineer that often had to diagnose various systems (power, electrical, ac, water .......... )) i learned you can not accurately diagnose without understanding how it works. I know I know ........ I had to study book after book and it would eventually pay off, no one else figured it out, i would but it may take 2 days of intense scrutiny !!!
Good luck and don't let up !

[HucklebuckRover]

i haven't worked on that model before BUT, it just looks like minimal movement and that the cylinder is too exposed to yes, either a adjustment or perhaps even the rod is the wrong length... ? hard to believe but either way I'd check the extremes and see how far either way by whatever means it could be adjusted ... you might discover something way wrong? keep us posted.
it's detective work!

It worked at some points so I think the rod is right - set it by the book again this morning to test it and it still wasn't working. I'll just have to troubleshoot -