931 Comfort King loader problems

Nighthawk450 · May 17, 2016

I have a 931 Comfort King with an EZ ON front end loader. Tractor is 8 speed diesel made in 1969. The loader uses a joystick control valve. The pressure line comes out the back of the pump and the return line goes in the side of the cover right above the pto. Everything worked great till the supply line blew yesterday. I replaced both lines and added about 7 gallons of fluid which I'm sure is way more than it lost so it must have been low already. Now the loader won't work at all. What could cause that?

Straw Boss · May 18, 2016

Just a real wild guess here, but we used to run a Du-al loader on a 1030 that would leak oil everywhere. If you didn't stay on top of it you would run low on oil, causing the pump to suck air, causing cavitation and pump failure.

Nighthawk450 · May 18, 2016

Loader doesn't leak any and wasn't leaking before the line blew. 3 point seams to work just fine but I don't have an implement on it so I don't know if it will lift weight.

Brokengun · May 18, 2016

If this were my tractor the first thing I would test would be the pressure at the remotes.

Was the hose bad?

I have heard of over pressure problems that blow the side out of the pump. Lets hope this didn't happen.

Nighthawk450 · May 18, 2016

Yes. The hose was bad. The loader worked fine till then but since I put it back together it won't work at all. Seams odd that it wold develop low pressure just because a hose blew. I will have to get my hands on a gauge to test the pressure.

Nighthawk450 · May 19, 2016

I found the problem. Anyone know where to get a replacement inner housing?

mEl · May 19, 2016

(quoted from post at 23:53:00 05/17/16) I have a 931 Comfort King with an EZ ON front end loader. Tractor is 8 speed diesel made in 1969. The loader uses a joystick control valve. The pressure line comes out the back of the pump and the return line goes in the side of the cover right above the pto. Everything worked great till the supply line blew yesterday. I replaced both lines and added about 7 gallons of fluid which I'm sure is way more than it lost so it must have been low already. Now the loader won't work at all. What could cause that?

Could you please post pics of the hookup, pump to valve the to sump, something created a great overpressure to both blow the line and split the pump at the same time, Valve plumbing also. Tnx. We would not want to repeat this with a new pump!!

Nighthawk450 · May 19, 2016

Can get pictures later but I have an idea what happened. The
line blew because it was old and weak. When I reconnected it
I crossed the supply and return line accidentally. I'm thinking
that might have been what blew the pump.

mEl · May 19, 2016

(quoted from post at 19:49:24 05/19/16) Can get pictures later but I have an idea what happened. The
line blew because it was old and weak. When I reconnected it
I crossed the supply and return line accidentally. I'm thinking
that might have been what blew the pump.

How was the tractor hydraulics tied into the circuit is my main area of concern.

Nighthawk450 · May 19, 2016

The top line in the picture that is connected to the tractor
hydraulic valve is the return from the loader valve (bottom).
The one on the lower right was disconnected from the
hydraulic pump output and goes to the loader valve input
(top).

mEl · May 22, 2016

(quoted from post at 21:56:37 05/19/16) The top line in the picture that is connected to the tractor
hydraulic valve is the return from the loader valve (bottom).
The one on the lower right was disconnected from the
hydraulic pump output and goes to the loader valve input
(top).

I got nothing but grief in other posts when I pointed out that that hookup is a recipe for disaster and your experience proves it. A valve in series MUST have a return line to allow the relief to work in the loader valve. When the valve downstream is under load all that backpressure goes against the backside of your loader relief rendering it worthless. If the tractor hydraulics are under any load, that pressure is added to the relief setting of the loader. You will probably get other opinions but I have been waiting for this complaint with pictures to come up. If a remote valve were accidently under pressure at the same time the loader was under heavy load the pump has no option except to fail. The top line is not a return it is the main hydraulic feed. If it were a return to sump you would have been fine.

Nighthawk450 · May 22, 2016

I understand what you are saying but I don't think that is what
caused the problem for me. The loader was the only thing
being used but when I put the new supply and return lines on I
accidentally hooked them up backwards.

Nighthawk450 · May 24, 2016

I'm thinking the way to solve this would be to put an in-line
pressure relief valve in the line where it comes out of the
pump. The pressure relief valve would have a return to sump
in case of overpressure. My question is how many PSI should
that pressure relief valve be?

931 Comfort King loader problems

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