MF 100 series Hydraulic Pump

[MF-ANDY]

When you say you got 3000 from the tipping pipe I assume you have selector valve and the linkage was isolated?

 

[aidan]

When you say you got 3000 from the tipping pipe I assume you have selector valve and the linkage was isolated?

Yes, constant pump and 3 way valve in external 2

 

[MF-ANDY]

Ok and you say cylinder and seals are new? New o ring between cylinder and top cover?
There is a shock valve in the selector valve, these can go weak.
I test with a selector valve that has the shock valve blocked off so it can't blow. The only real check is to replace the selector valve with a transfer cap then test at the 3/8 port on the top lh side of the cover.

 

[aidan]

Ok and you say cylinder and seals are new? New o ring between cylinder and top cover?
There is a shock valve in the selector valve, these can go weak.
I test with a selector valve that has the shock valve blocked off so it can't blow. The only real check is to replace the selector valve with a transfer cap then test at the 3/8 port on the top lh side of the cover.

Yes new cylinder new piston rings and new O ring

We were at 3000 psi in the lift cylinder before any repairs

What does the slider down near the dipstick do, does it have any influence on pressure anywhere

 

[MF-ANDY]

It's response control. It stops the control valve moving quickly thereby stopping the arms fluctuating when in draft. It only works on the lowering side of the control valve so it can be used as a rate of drop control too.
I would remove the selector valve, and on the mounting face you will see a large hollow screw type bung. Remove this and the spring behind it. Replace the spring with a cut down bolt then replace the bung and tighten it until it clamps the ball bearing that was held by the spring. Refit the selector valve and test at the 3/8 port on the lh top of the top cover with valve in linkage. You can't do any harm as the the pressure control valve will prevent any over load.
Have you got a new oring between the selector valve and top cover?

 

[aidan]

It's response control. It stops the control valve moving quickly thereby stopping the arms fluctuating when in draft. It only works on the lowering side of the control valve so it can be used as a rate of drop control too.
I would remove the selector valve, and on the mounting face you will see a large hollow screw type bung. Remove this and the spring behind it. Replace the spring with a cut down bolt then replace the bung and tighten it until it clamps the ball bearing that was held by the spring. Refit the selector valve and test at the 3/8 port on the lh top of the top cover with valve in linkage. You can't do any harm as the the pressure control valve will prevent any over load.
Have you got a new oring between the selector valve and top cover?

Yes mechanic fitted new O ring

Your suspecting either that shock valve you mention or leaking lift cylinder or leaking O ring ?

 

[MF-ANDY]

Well if you get 3000 from external 2 the pump is obviously working correctly and the orings on the stack pipe are ok. That leaves shock valve, cylinder seals or cylinder oring

 

[aidan]

Well if you get 3000 from external 2 the pump is obviously working correctly and the orings on the stack pipe are ok. That leaves shock valve, cylinder seals or cylinder oring

will hopefully get a chance to have a look this weekend. was wondering when i remove the sidecover where the dipstick is, with the aid of a borescope shoudl i be able to see where it is leaking when i put a load on the lift arms

 

[MF-ANDY]

will hopefully get a chance to have a look this weekend. was wondering when i remove the sidecover where the dipstick is, with the aid of a borescope shoudl i be able to see where it is leaking when i put a load on the lift arms

Yes possibly

 

[aidan]

It's response control. It stops the control valve moving quickly thereby stopping the arms fluctuating when in draft. It only works on the lowering side of the control valve so it can be used as a rate of drop control too.

I would remove the selector valve, and on the mounting face you will see a large hollow screw type bung. Remove this and the spring behind it. Replace the spring with a cut down bolt then replace the bung and tighten it until it clamps the ball bearing that was held by the spring. Refit the selector valve and test at the 3/8 port on the lh top of the top cover with valve in linkage. You can't do any harm as the the pressure control valve will prevent any over load.
Have you got a new oring between the selector valve and top cover?

is this operation you describe here isolating the shock valve or is this another valve

 

[MF-ANDY]

is this operation you describe here isolating the shock valve or is this another valve

It is stopping the shock valve in the selector valve from opening so if you then get good pressure it must be the fault

 

[aidan]

It's something do with the draft control is the problem, I can get 3000psi in the lift cylinder with yard scraper attached which gives a tiny pull on top link and only 1500 psi in the lift cylinder with a fert spreader and 500kg on board which gives more of a pull.

See photos attached of draft control lever position. That hose is where I am measuring the pressure.

 

[MF-ANDY]

Broken or weak draft control spring then. Easy to remove and check as long as the ring nut isn't sized.

 

[aidan]

Broken or weak draft control spring then. Easy to remove and check as long as the ring nut isn't sized.

Can it be done through the side opening or top cover off again

Can it be adjusted to tighten it even through side window

All draft related stuff was fine before this project started,

Broken or weak draft control spring then. Easy to remove and check as long as the ring nut isn't sized.

 

[MF-ANDY]

Can it be done through the side opening or top cover off again

Can it be adjusted to tighten it even through side window

All draft related stuff was fine before this project started,

It's behind where the top link connects in the tubular part of the top cover casting. Remove the top pin from the bracket that the top link pins to (lambs tail). Pull back the rubber cover and you will see a ring nut with internal grooves. There is a small grub screw in the side of the casting that locks the ring. Undo the screw and remove the ring and whole assembly will come out. However the grub screw and ring will probably need heat to get them out. If you get it out, come back and I will explain the adjustment.

 

[aidan]

It's behind where the top link connects in the tubular part of the top cover casting. Remove the top pin from the bracket that the top link pins to (lambs tail). Pull back the rubber cover and you will see a ring nut with internal grooves. There is a small grub screw in the side of the casting that locks the ring. Undo the screw and remove the ring and whole assembly will come out. However the grub screw and ring will probably need heat to get them out. If you get it out, come back and I will explain the adjustment.

was checking on this last Sunday, with the draft lever turned off, i.e. put in the transport position the entire spring assembly is solid, with the draft lever moved to allow the draft to work, there is 3mm play in that spring.

would my description indicated that is correct.

Must give the toplink a good pull and then check the pressure which goes to the lift cylinder next.

 

[MF-ANDY]

The adjustment is to screw the ring nut in so there is no end play. That is after you have removed the assembly and adjusted the spring on it retainer.

 

[aidan]

The adjustment is to screw the ring nut in so there is no end play. That is after you have removed the assembly and adjusted the spring on it retainer.

what position should draft lever and position control levers be in to check

 

[MF-ANDY]

what position should draft lever and position control levers be in to check

Iirc, position transport, draft down.