656 Hydraulics- No Pressure

[Scott(MO)]

Hello,
I have a question about why no hydraulic pressure on our 656 Farmall? I was putting out hay for the cows and picked up a bale & put it in the ring. Then I back up to the shed to run a couple cows out and when I went to get off, I dropped the loader down on the ground to act as a E-brake (not enough to raise the front end, just down on the ground). When I got back on, I couldn't raise the loader. It wouldn't budge, like it had no pressure. I figured maybe a relief valve as I had trouble with it a few years ago. I took it apart, nothing wrong there. I pulled the 3 point plate to look back there in the rear end and I see circulation, but I haven't drain the rear to check the hose. I put a gauge on the remotes and it reads 0 PSI. I have no loader, no rear remotes, no 3 point and no steering. The pump was replaced 2 or 3 years ago and everything has been working good up until now. Any suggestions? Thanks in advance!

 

[d rushlo]

CHECK SEE IF PTO WORKS IF NOT POSIBLY SPLINES IN PRUSHER PLATE THAT DRIVES ALL HYD. AND PTO

 

[Scott(MO)]

The PTO works.

 

[old]

Might be a long shot but when was the last time you changed/cleaned the hyd filter

 

[Janicholson]

I would look up into the access inspection plate at the clutch to see if the drive coupling tube splines are stripped. That is common. There are splines in the Pressure plate, and splines on the shaft tube part 6. The clutch Pressure plate has splines in the center that drive the IPTO gear part which drives the hydraulic pumps. Jim
Transnission showing the PTO drive tube

The clutch

 

[Janicholson]

The PTO might spin, but is it powered, or just moving because it is not loaded. If you watch it spin, while someone trys to lift the loader, it will stop. (my best guess). The fix (if it is the splines) is a new shaft, and a new clutch Pressure plate, (or clutch Kit there will be no shaft in the clutch kit) Jim

 

[Janicholson]

A little more from the forum Jim
Untitled URL Link

 

[caterpillar guy]

Like Jim said the pto will turn until you load it. Or try as he said watch as you try other funtions and it will probably stop turning. Sounds like split time.

 

[Scott(MO)]

It's been awhile, but I don't think it would go from working fine to 0 psi pressure while sitting running for 2 minutes. But it does need a change.

 

[Scott(MO)]

Thanks for the info Jim...I will check today.....I hope you're wrong...LOL, but it's more probable than not that you're right. Thanks again!

 

[DeltaSteve]

Could be ice crystals plugging the filter. If it's been a while since you changed oil/filter,now might be a good time to do it.The little bit of water can form ice crystals in cold weather,plugging a filter.Or as said above,PTO drive and pressiure plate are stripped. Do the easy first. Chang hydralic oil and filter.At bare minimum,the filter.

 

[Scott(MO)]

Well, I checked the shaft going to the pressure plate and it was spinning OK. So I wired the lever back on the loader to raise it and looked at the shaft and it is still spinning, but still no pressure....weird!

 

[karl f]

The bearing on the pto driven gear (behind the hydraulic pump) can go out. It will sound like grinding coffee under hydraulic or pto load as the gear flexes away from its normal operating position. You will need a new pair of gears, a new driven shaft, a couple bearings, and worst case scenario a bored out ta housing with custom made press fit sleeve to house the bearings. I hope it is a cheaper repair for your sake. Maybe a sheared pump key or failed steering flow divider--the rear remote flow primarily comes from the steering pump on a 656.

Karl f

 

[Janicholson]

The drive gear on the pump shaft (input) can come off. jacking up the pump side a foot at the axle housing will keep most of the oil inside, you could detect the drive status of the pump at the pump. Jim

 

[used red MN]

(quoted from post at 00:08:53 12/19/20) Hello,
I have a question about why no hydraulic pressure on our 656 Farmall? I was putting out hay for the cows and picked up a bale & put it in the ring. Then I back up to the shed to run a couple cows out and when I went to get off, I dropped the loader down on the ground to act as a E-brake (not enough to raise the front end, just down on the ground). When I got back on, I couldn't raise the loader. It wouldn't budge, like it had no pressure. I figured maybe a relief valve as I had trouble with it a few years ago. I took it apart, nothing wrong there. I pulled the 3 point plate to look back there in the rear end and I see circulation, but I haven't drain the rear to check the hose. I put a gauge on the remotes and it reads 0 PSI. I have no loader, no rear remotes, no 3 point and no steering. The pump was replaced 2 or 3 years ago and everything has been working good up until now. Any suggestions? Thanks in advance!

I am just kind of an arm chair mechanic on this problem, but have some additional interest because I spent quite a bit of seat time on a 656 growing up back on the farm. When you talk about the relief valve are you talking about the one that screws into the body that the remote cylinder controls bolt onto? I only know of the location as it is described by Pete23 in this Red Power post.
https://www.redpowermagazine.com/forums/topic/64347-farmall-656-hydraulics/ In that post the scenario is he has 3 point lift and PS but no auxiliaries. I am pretty sure these tractor use the pilot operated pressure system IH came out with in the mid 50s on the 100 series. I dont know where the pilot valve is on the 656 but I understand if a screen plugs in there or something dislodges a check valve in it the hydraulic system cant come up to pressure. That valve is shown in this diagram. https://avspare.com/catalog/case/50755/54490/1294139/ I am not sure what this will do for you. I hope your pump isnt messed up again but that seems to be what one can expect when you use older equipment.

 

[Scott(MO)]

I was planning on draining the fluid tomorrow and checking the pump. Jacking up the tractor on one side to keep most of the fluid in sounds like a good idea. I think I will give that a try first instead of draining all the fluid. Thanks for the tip!

 

[Scott(MO)]

Yes, that's the pressure relief valve I was talking about. I originally thought that was the problem and started there first by taking it apart. I had it mess up one other time and took it apart and fixed it. But this time it all looked good with no issues. That's when I started checking everything else and realized I had no pressure anywhere else.