MF3090 No Clutch Hydraulic Pressure or Disengage?

[MX45]

Hi, just another day in paradise! Just spent a bit of time taking out the old Master Cylinder to find the seal hard and the cylinder certainly worn to one side with very mild scoring. I did this as a result of virtually total clutch fail. Since it has creeper gears I can actually move it around very very slowly without the clutch as I can engage super low Forward and Reverse without the clutch. I had earlier acquired the new Master Cylinder having had the original leaking externally although it was more of what I would call a weeping. I thought maybe the seals were being bypassed with the pressure and so diagnosed faulty Master Cylinder. I am wrong!!!

The clutch is still not present with any pressure at all. I do not appear to have any sort of fluid leak under the tractor if it were slave cylinder??? There is plenty of fluid in the transmission and all other hydraulic operated items work, ie brakes, steering, remotes for rear and front on all outlets/inlets as per normal. There are no error codes in the display panel in front of the driver. Prior to this clutch fail the automatic gear for up and down without clutch failed but not at the same time and I suspect electrical fault with that one.

Any experienced suggestions from MF3090 owners. Tractor has near 11700 hours on it, lives outside and is in average but very functional condition.

Where do I begin??? Maybe a new tractor???

How would a 5435 compare with the 3090 as there is one for sale???

Thanks, MX45

 

[MX45]

Hi, on further looking at it and testing I clamped off the pipe running from the master cylinder to the slave cylinder and can get no pressure with new Master Cylinder. I have oil running out of the master cylinder connection on relieving tension on the hydraulic connector so there is oil in the Master Cylinder and oil coming out of the slave cylinder return to reservoir. I notice there is a valve block between the master cylinder and the slave cylinder??? Any guide as to what goes on there that could be a cause or is it possibly the supply pressure to the master cylinder? I also cannot find the bleed nipple that is talked about for the system?

 

[MX45]

Found the bleed nipple. Fluid is present after the Master Cylinder to the input to the slave cylinder and after at the pressure relief bleed nipple. So starting to lose possibilities as to what is wrong???

 

[MX45]

I have run the motor and not run the motor and their is a pressure pulse when the clutch pedal is depressed from the bleed nipple with extra flow of oil. Clearly there is pressure in the system??? However having opened the inspection plate for the clutch assembly and the annular salve cylinder there is no movement whatsoever in the annular slave cylinder??? While there is a weep of oil over the external dust cover there is no pulse of oil or other evidence of a leak to match the hundreds of times the clutch has been pressed to push fluid through???? Is it possible for the pressure from the Master Cylinder to bypass the clutch slave cylinder somehow???

 

[Welder Dave]

Is there a booster in addition to the master cylinder that could be bad? That might be the valve block you mentioned?? If so might be run off of the steering pump. I had to get a new master cylinder and the booster rebuilt on a Champion grader clutch and now I need a new slave cylinder because it started leaking. Over $2000 to have a working clutch.

 

[MX45]

Thanks Dave, I don't have a manual so the valve block is a mystery to me. The supply side of the Master Cylinder comes from the valve block. I will have a look to see what else it serves tomorrow. Certainly the brake pedal seems to be higher than usual so maybe extra pressure there? But when you start looking when you have not looked or measured for a while anything looks suspicious. I followed operation of everything that operates off of the hydraulic pump and everything else operates the way it is supposed to. The only thing I can add on recent history is that the fail happened gradually, ie the gears were a bit harsh to change and the clutch was lower to the floor. The total disappearance of clutch pressure however was one time it all worked and the next time it was on the floor. I don't see any booster on the clutch or brake circuit that I know of? Thanks for suggesting anything I can look at.

 

[MX45]

NB I have had a look at the valve body and it powers the steering, brakes,clutch. The clutch take off banjo is at the lowest point of the valve body so if something were to fall/fail in the valve body it would fall to the lowest point and while it has not completely blocked the pressure distribution to the clutch it may well have. The banjo is quite small as well so the delivery hole would be smaller again. Worth a shot! A job for the next few days as I try to get some other work done.

 

[MX45]

Morning, back at tinkering. So opened up the supply port from the valve bank and was disappointed that there was only very fine sludge and no blockage ruling it out as a cause. However very little oil present? So I bled the valve assembly by running the motor and leaving the banjo loose and got dirty oil at first and then clean oil. Subsequently I bled a little bit of air from the clutch bleed outlet and got a little bit of clutch pedal!!! I then adjusted the master cylinder piston rod threaded connection to the pedal and got pedal enough to be able to change gears. However lost contact with the safety start switch at pedal full depression. Will adjust and get the machine going again. I think persistence and a combination of smaller things was preventing clutch performance. I can only see how it goes from here with a bit more knowledge. Hope this post assists someone else.

 

[Welder Dave]

What was the sludge from? I'd want to flush the system and try to figure that out so it doesn't come back to haunt you.

 

[MX45]

Hi, it was a very fine black dust and I would expect with the machine with nearly 11700hrs on it and although new fluid was put in the system was not flushed as it is supplied from the main transmission reservoir that goes through everything hydraulic on the machine. Could be brake dust, etc. It was a very small amount but a bit surprised that it had clearly lodged in other parts of the valve body that flushed when I left that Banjo open. I am only talking about less than 10 seconds likely 5 seconds before it ran clean. In any event drove the machine today and for about an hour and clutch improved to the point I had to lower to the floor a bit more to have it's take up in a sensible place. I will know tomorrow morning if I lose that pressure overnight or not? So far so good, touch wood. NB Machine did most hours with a contractor although I have owned it for likely 20 years and done a few myself. Previous owner was light on maintenance to be kind.