Re: FARMALL 656 HYDRAULICS which pump does what?

Posted by TX656 on August 16, 2008 at 21:19:37 from (71.48.164.202):

In Reply to: FARMALL 656 HYDRAULICS which pump does what? posted by rustnsuch on August 16, 2008 at 11:39:45:

Pretty much what Allen said but if your looking for something formal the following is straight from the IH Blue Ribbon Service Manual #GSS-1383 Chassis 656 Series Tractor....

HYDRAULIC AND LUBRICATION SYSTEM

There are two pumps located in the clutch housing and one in the IPTO housing. All use a common fluid supply which furnishes fluid and lubrication for the power steering, transmission and final drive, IPTO and the auxiliary valves.

Power Steering and Auxiliary Valve Supply

The pump output, regulated at 1,600 psi goes to the flow-divider and 3.5 gpm at priority is diverted to the power steering valve. When power steering is not in use this flow goes through the valve to the cooler and from the cooler to the tee located in the left side of the clutch housing. A small amount goes down into the clutch housing through an orifice. This orifice dumps below fluid level at all times and is for the sole purpose of supplying make-up fluid during manual steering.

The balance goes to the lower port on the load control junction block and lubricates the differential and bull pinion bearings. There is a check valve in this block for the purpose of closing off the suction during manual steering.

During power steering the flow goes to one side of the cylinder and the return fluid out of the other side of the cylinder goes back through the power steering valve and follows the route described above.

There is an oil cooler by-pass relief valve (90 psi) in the right side of the clutch housing which goes back to dump. This valve is to by-pass the cooler for a quick warm-up of fluid and to provide relief if the cooler becomes restricted. The remaining flow from this pump goes to the junction block on the right hand side of the load control. When no demand is present, this flow goes through the open center valves to the suction pipe in the frame sump. When the auxiliary valves are placed on demand, the flow goes through the open center valve to the cylinder in use.

Hitch and Supplemental Auxiliary Valve Supply

The hitch pump flow goes back to the top port on the junction block on the load control and to the load control valve. When neither the hitch nor the auxilary valves are on demand, the fluid goes through the check valve in the junction block through the open center valves back to the suction line to the sump.

When the hitch alone is activated to raise, the flow goes through the control valve to the cylinder. When the hitch is activated to lower, the fluid from the pump goes as described above.

The fluid from the cylinder goes through the action control valve to the load control housing, the overflow pipe returns it to the sump. This flow going to the hitch is available for the auxiliary valves if not required for the hitch.

When the hitch and the auxiliary valves are placed on demand the hitch will move independently of demand of auxiliary valve system. This means that the flow from both pumps would be available for the auxiliary valves after the hitch demand is satisfied. The flow for the auxiliary valves is not available to the hitch because of a check valve in the junction block.

Auxiliary pump 1550-1600 psi

Hitch pump - 1950-2000 psi

Hitch relief valve opening pressure 1700-2000 psi

End quote, begin comment...

I think a new piggy back pump is getting close to $500? You can get a wear plate kit and gaskets from CIH for about $83. I don't have any 3 point implements of that size so I don't know how effective the $83 kit was. I just did it because I had opened up the piggy back pump while putting in a new 17 GPM main pump. Don't forget to order the miscellaneous o-rings and pump body gasket if you go this route. Not all of them are in the kit.

Replies:

• Re: FARMALL 656 HYDRAULICS which pump does what? rustnsuch 18:40:10 08/17/08 (0)

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