MF285 Auxillary Hydraulic Issue

[IFF]

I am having issues with the auxillary hydraulics on my MF285. I hooked a pressure gauge up to the remote coupler and got an initial pressure reading of ~1100 psi which immediately dropped to ~700 psi. This was the same on both remote couplers. I have had this issue since I got the tractor. I had the tractor split a couple of years ago and the auxillary pump looked fine from a visual perspective. I"m not quite sure what to do next. I don"t know if I have a bypass valve opening too soon or if something else is wrong. I need some ideas on what to do next.

Doug

 

[DavidP, South Wales]

Hi Doug,
My info shows that 3 different pumps were fitted to the 285 in addition to the single element ones. The layout will be very similar. When you had the aux pump removed did you strip it and inspect it for wear? Wear can take place in the bushings but particularly in the aluminium body around the outside of the gears. Wear here will certainly reduce output and ultimately maximum pressure.

The parts book for the 285 does not show the rectangular filter similar to the size of a cigarette packet only the inclined one accessible through the underside of the centre housing via the three bolt plate. Do you have this type. You may of course still have the square filter.

This would appear to be a filter or reduced intake problem. As a first step, drain the oil and remove the filter if you have that type. Unfortunately access to the aux pump is via the front opening of the centre housing after you have split the tractor.

Please give us any more info that you can.

DavidP, South Wales

 

[IFF]

David,

When I had the tractor split I took the pump out and opened it up. The gears felt tight and there was no visible scoring on the aluminum housing. I wish now that I had taken some measurements of the clearances. I replaced the filter which I recall was round. I have a four basket Krone tedder which the tractor is able to fold/unfold when I first start it up and things are cold. If I run the tractor for a while it is not able to fold up the tedder.

Doug

 

[DavidP, South Wales]

Hi Doug,
What features does your tractor have?
Auxilliary supply yes, Multi-Power, independant PTO?
Do you have any idea of the number of working hours that the pump may have done?
Did you renew all of the seals at the time of inspection? If there is wear in the bushings you may be losing oil past here and/or perhaps through the main seal if fitted.
There is a possibility that you may have a leaking or split pipe internally. Drain the oil to the level of the bottom bolt on the RH round side cover. Remove the cover. This will be a little more difficult if you have a cab fitted.
Get yourself into a position where using a flashlight you can see as much of the inside of the casing as possible.
Have an assistant start the engine and operate one of the aux levers. You should see oil coming from the relief valve.
Look for oil coming from anywhere else. It's not a conclusive test but it might help.

The 285 was not available in the UK so I can't be more specific. I expect it was very similar to our 290.

I suspect that removing the pump and a further examination will be necessary.

Cheers

DavidP

 

[IFF]

David,

The tractor has multi-power and IPTO which both work fine. I will pull the side cover and see what is going on. If I can't figure this out without splitting the tractor I may install a second external pump driven off the front of the engine to supply the remotes. Thank you for your input.

Doug

 

[Dieseltech]

Can you put your pressure gauge on line from pump to spool valve, take valve out of circuit and test again? Pump may be fine, but valve may be faulty. May be worth a try.

 

[IFF]

Good idea. Thanks

 

[DavidP, South Wales]

Hi,
That would certainly be an interesting project but would require sufficient planning. Ideally you should install a suitable filter, relief valve and supply pipe of larger diameter than the output pipe.
DavidP