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Need help with 656 Hydraulic Problems

Glenn Hello,

I have a 656 gear drive that has lost hydraulic power to the power steering, loader and 3 pt. I guess there is a small amount of pressure as the 3 pt. will slowly lift the mower about a foot after several minutes.

I've inspected the check valve screen and filter and they looked OK. What can I do to check the pump? What else could be wrong? What else can I check?

Any help will be greatly appreciated.


jim Does pto work ok, all driven from same splines on clutch backing plate. You have two seperate pumps and relief valves,hitch pump mounts piggy back on main pump so doubt it is pump. Could have blown the return hose inside rear end so it sucks air, can inspect that through the 3rd arm plate above pto. Late model tractors have a metal tube instead of hose and it can break also. Also, main suction tube can break loose in rear end. Several other things possible also.
Glenn Thanks for the suggestions Jim.

The PTO works. I removed and inspected the pump and it seem ok - turns free, etc. I can put my palm on the inlet tube from the filter, turn the gear and feel suction. For what ever that's worth.

I'll check out the 3rd arm plate tomorrow.


Glenn I took off the 3rd arm plate and the rubber return hose looked OK. With the tractor running, I could see the hydraulic fluid moving around in the bottom of the case. Also, some was spraying down from the top somewhere and I could see some running down a bearing housing. So it looks like some hydraulic fluid is being pumped.

The steering wheel turns free when the tractor isn't running. Must be air in the system. After starting the tractor, I can turn the steering wheel to the right a number of times and it finally catches and turns the wheels. But it's very hard to turn. Turning back to the left is also very hard to turn.

Anybody have any ideas what I can check next?



jim The thing that is bugging me here is you say hitch also does not work and that has it's own seperate pump and if the hitch is not being used that flow joins the flow from the main pump to add to the flow available at the aux valves for loader etc. That is why I have been thinking that it is a supply issue to both pumps. Could be a spun key on shaft of pump that turns somewhat but I severly doubt that. If it was stuck flow divider you would still have hitch unless you do not have a factory hitch and it is an add on working right off the main pump. I know what I would do but this is tricky. I would take the pressure hose off right at the main pump and plumb it into a restrictor with a gauge on it. Flow rater with built in relief valve works fine, I'm sure you don't have one and neither do I , dealer ship had that. Reason I say it is tricky is you will have no relief valve in system and you can blow a pump if not very cautious. Steering has first choice at flow through the orfice in flow divider block. That is the one where those two large hoses come into and out directly from pump. Seperate relief valve for steering in there also could be dumping most of oil but then hitch should work anyway. Keep trying is all I can say with out being able to get my hands on the tractor to test.
Glenn I may have found something. Last night I took the pump out and removed it from the flange. The two o-rings between the pump and the flange were gone. That could explain why there is no pressure on either main and hitch systems.
jim Now, that could well be the problem, question is , when did they disappear or get left out.
Glenn The problem was resolved with a new pump.

Thanks for everyone's input.


leeflick Lift arms are lifting slower than normal changed filter made a diference butstill slow at first wouldnt lift grader blade at idle but will now and it takes about a min idle up and works normal

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