MB Trac clutch bleeding.

[renewablejohn]

Have just fitted a new clutch slave cylinder and trying to bleed it doing the normal plastic tube in a bottle trick. Clutch pedal remains rock solid but will go down as you bleed it. Have even lifted clutch lever up fully retracting slave cylinder and then tightened bleed nipple up. First pump of pedal and the pedal is rock solid again. Any suggestions what I am doing wrong or do you think its sods law that both the clutch cylinder and slave cylinder have gone at the same time.

[gensetsteve]

Not done an MB trac but had similar problem on a disco we had to get the bleed nipple at highest point by jacking vehicle way up in the air. Otherwise a small air bubble got caught in top of slave cylinder. The other thing is to let it settle over night and gently bleed last of air out in morning.

[david]

would air in the system make the pedal go solid?

 

can you using the pedal to pump fluid threw to the salve cylinder blead nipple?

[Wainy]

have you tried bleeding it the other way round, forcing the fluid in through the bleed nipple. works a treat on stubborn systems we use a bottle with a rubber tube drilled into the lid with a tubeless tyre valve drilled into the base, stick pipe over nipple hold bottle upside down and pump up with footpump (not too much!) wait till no bubbles appear in reservoir but watch it doesn't overflow.

[woody paul]

Take slave cylinder off leaving pipes joined and see if it works as it should. Then if it do's you have got a clutch problem. On FENDT tractors you bleed them piped but not bolted on tractor then you have to get it bolted to tractor not easy as you have to push slave cylinder in and the fluid go's back in to reservior so make sure the level is low first.

[Tyz05]

I've never worked on a mb trac but I'm assuming you have an external slave cylinder operating a mechanical linkage? At a guess I would say the slave cylinder is stuck out at full travel and not being forced back by the linkage. Once the system is full of fluid and clear of air there is no way of displacing the fluid because the cylinder is already at full travel. Try adjusting the linkage and make sure it's free. Only thing I can think of. Wouldn't have thought from the symptoms you describing that there is a fault with the master cylinder.

[renewablejohn]

Thanks all

 

At the moment I have connected a pipe to the bleed nipple on the slave cylinder with the pipe higher than the master cylinder. Pressing the pedal pumps fluid out the pipe. I will leave overnight to see if air bubbles migrate out. Looking at my other MB Trac the clutch lever seems to compress the slave cylinder by half whereas the slave cylinder is fully extended on the one I am trying to fix. Although it will compress with the use of a crow bar. Is there a spring mechanism in the clutch which compresses the slave cylinder.

[Tyz05]

Thanks all

 

At the moment I have connected a pipe to the bleed nipple on the slave cylinder with the pipe higher than the master cylinder. Pressing the pedal pumps fluid out the pipe. I will leave overnight to see if air bubbles migrate out. Looking at my other MB Trac the clutch lever seems to compress the slave cylinder by half whereas the slave cylinder is fully extended on the one I am trying to fix. Although it will compress with the use of a crow bar. Is there a spring mechanism in the clutch which compresses the slave cylinder.

 

The pressure of the clutch plate cover should cause the linkage to return the cylinder to it's inward position,there may be an assistor spring of some description depending on wether the thrust bearing is constant running type or not. Sounds like the linkage requires adjustment or the cluch cover or release mechanism is excessively worn. Job to say without seeing though.

[skyhuck]

What symptoms made you change the slave cylinder????

[renewablejohn]

What symptoms made you change the slave cylinder????

 

Started tractor up and tried to put in gear it appeared the clutch was not working. Checked clutch fluid level and it was two thirds down so topped up and retried still did not work. Followed pipes down for leaks and slave cylinder rubber boot split with pin dangling down. (Basically slave cylinder u/s). Bought new slave cylinder and fitted.

 

Clutch has not been adjusted since I bought the MB Trac so will see what I need to do to adjust it if no joy with bleeding overnight.