MF250 Hydraulic Problems

[Keycare]

Hi All,

I am try to fault find a problem with my hydraulics on my MF250. I have the workshop manual, but I am struggling with the poor picture quality, number of variations and terminology. I've watched youtube videos etc but am still drawing a blank.

Basically, neither the lift arms nor the loader work. They did last year, albeit a bit juddery sometimes, but I have been rebuilding the engine so it was idle for about 1 year. When I started it, it all seemed to work fine, then the hydraulics just stopped working.

At first, the arms would lift when in transport position after the tractor was started, however, adjusting position control after that meant they no longer responded, until the engine was turned off, waited and switched on again, then the arms would lift. I thought it was the control valve (roller valve behind the dipstick cover). It was a little sticky, but now it moves freely and there is still no lift. There appears to be flow from the standpipe, but I don't know if it is enough to create the pressure required. So I thought it might be the pressure relief valve. I once again took the lift cover off, but cannot see any relief value - see link.

MF250 Hydraulics

I am also struggling to identify what's what. It has an hydraulic pto clutch, but that is also not working so the pto is constantly engaged.

I was going to try and remove the pump, but I cannot twist the driveshaft in order to remove the cotter pin. Shouldn't it move freely when it's out of gear? There is simply no room to remove the pin if I can't twist the shaft.

Can any one shed any light on this arrangement, and the components in the picture?

Much appreciated.

 

[Harry in Ky]

To start with, the drive coupler is splined onto the pinion shaft. It turns when the tractor rolls, no mater whether in any gear or neutral.

Second, before you go into the pump, drain the rear end and remove the small three cornered tin plate under the pump. Then you can remove and clean the suction screen. That may well be all it needs.

 

[Keycare]

Thanks.
Yes, I have cleaned out the filter once but I think you are right that it would be wise to do it again. Looking at the chamber, there is still some bits and sludge in there.
Is it a bad idea to put a few litres of diesel in there are run the tractor for a few minutes as a kind of flush. Will that do more harm than good?

 

[Harry in Ky]

Some people do that. Personally, I'm not a fan of the concept. If the lift cover is off, I would pour some through, scrub a little, flush and then let it drain out. But running it with diesel instead of oil? That I have never done, and probably never will.

 

[masseyrider]

We had a pair of 250s bought new.
Couldn't get rid of them fast enough.
Hydraulic problems, wet brake issues, exhaust rotting out, tie rod ends falling out in 250 hrs...
Pieces of junk.

 

[Keycare]

Thanks massey rider, helpful.

 

[Keycare]

One thing I can't see in that picture is a pressure relief valve. Does it have one, if not how does it regulate hydraulic pressure?

 

[Harry in Ky]

The relief valve is a preset self contained little unit, usually threaded into the lift pump somewhere. If you have external hydraulic remote valves there will be another relief in that unit as well, but that is for the auxiliary pump circuit, and has no effect on the three point.

 

[masseyrider]

Thanks massey rider, helpful.

Just saying that all the 250s I've known were flawed machines. Not just ours but machines others had.
We've had everything from the early little grey fergies through 35s, 135s, 230, 235, 245, 255, 265, 243. 253, 263, 461, 563 gc 2310, gc1725M and a few I've probably forgotten. Hence MasseyRider.
Never knew 2 pieces of scrap iron like the 250s we had.

 

[Keycare]

Just saying that all the 250s I've known were flawed machines. Not just ours but machines others had.
We've had everything from the early little grey fergies through 35s, 135s, 230, 235, 245, 255, 265, 243. 253, 263, 461, 563 gc 2310, gc1725M and a few I've probably forgotten. Hence MasseyRider.
Never knew 2 pieces of scrap iron like the 250s we had.

OK. but it doesn't help me though.

I *have* a MF250, I am not going to scrap it. I've just rebuilt the engine and cannot afford to buy another tractor. I need a tractor, so I need to fix mine. Telling me that they are ***** is something you should reserve for threads asking if MF250's are any good and not for someone asking for advice on how to fix one.

 

[Keycare]

The relief valve is a preset self contained little unit, usually threaded into the lift pump somewhere. If you have external hydraulic remote valves there will be another relief in that unit as well, but that is for the auxiliary pump circuit, and has no effect on the three point.

Hi Harry, I bought a replacement in the hope that the relief valve was the problem, but cannot see a similar part in the chamber.

The service manual shows the relief valve in Fig.231 item 7.

My pump seems to match the illustration on Fig 237, which does not have the relief valve as shown in Fig. 231??? but does have the pump servo assembly that isn't in Fig 231. Does the servo act as a pressure relief valve?

I was working on the assumption that if I have flow, then the problem would be lack of pressure and I hoped that it was a failed pressure relief valve that might be the culprit. This means I might be heading down the wrong path.

I remember experiencing judder upon lifting, so am still wondering if a pump overhaul is required.

 

[Harry in Ky]

If your pump looks more like fig. 231 then the tractor must be equipped with pressure control. That was an option, not all tractors came with it. If so, then yes the standard relief valve will not be in the mix.

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