Nick Faessler's Oliver Fleetline Hydraulic Pump Repair

     Here is the place to find everything you need to refurbish any Oliver Fleetline hydraulic pump. This style pump is on all Oliver row crop and standard tractors in the Fleetline, Super, and Three Digit series. The 66 through 660 uses a three quarter inch center plate and pump gears, while all others use a one and one eighth inch plate. The bearings, gears, seals and endplates are the same in all the model tractors.
I contract to engineer centerplates in Wisconsin in a small shop that does excellent work for me. The plates are of a high quality ductile cast iron very similar to the original pumps.
I also manufacture the pump gears in this area. The drive sleeve is a rebuilt part because a new sleeve was much too costly to produce.

Disassembly

Overview

     The Oliver hydraulic in the Fleetlines, Supers, and Three Digit tractors is a bit unique from other manufacturers of tractors as it is a stand-alone unit. The system is a single unit containing the pump, reservoir, filter, relief valve and controls. This made it a rather simple installation for tractors that left the factory without a hydraulic unit. A tractor could be field converted fairly simply from no lift unit or from a clutch lift to the self-contained hydraulic system.
     The unit needs to be disassembled when there is a loss of fluid. There could be a sudden loss, usually a cracked centerplate. The loss of oil could be more gradual, the likely causes from poor pump seals. The mounting o-rings could also be faulty. It also needs to be removed when the pump will no longer produce the pressure needed to do its job.
     The pump could have a slight loss of flow, which can indicate a worn pump. The pump can operate at a pressure too low to lift needed implements.

Removal and Disassembly

     Prior to removal, the oil should be removed from the system. This can be done by attaching a hose to the hydraulic coupler and empty the unit at an idle. Stop the engine as soon as the pump quits pumping oil. The unit can be removed from the tractor by first removing the PTO shield, the PTO cover, and lastly the PTO clutch and live shaft assembly. There are three bolts in front of the clutch that allow the PTO live shaft to be pulled out. Remove the seat assembly from the rear of the frame to allow more room to work. Remove all ten bolts. The unit can now be lifted from the tractor. You can now remove the pump from the bottom of the unit.

Inspection

     To disassemble the pump, clamp the front flange in a vice protected with some cardboard to prevent damage to the o-ring surface. Drive the dowel pins part way out of the pump and remove the wires on the bolts. Not all pumps are wired. Remove the rear end plate to just inspect the pump. Drive the dowels all the way out and remove the bolts and disassemble.
     Look at the centerplate for cracks. These can break from water in the system and freezing. The plate will also break from excess pressure from the relief valve set too high. 1200 PSI should be the maximum to run the system. The pressure can also run too high if the relief valve seat is loose in the base plate. Pressure will push it and the relief valve plunger out toward the spring and not relief oil to the reservoir. The excess pressure can damage the pump. Be sure to check the relief valve seat.
     The gears should not have material on the tips of the gears and the sides. The end plates should be smooth and not have wear marks that catch your fingernail when you drag it across the plate. End plates can be reground by a machine shop. The shafts should smooth on the bearing and seal surfaces. Any excessive roughness will cause premature bearing failure. If the shafts have worn beyond allowable specs, the bearings will not hold the shafts in the correct position and the pump will likely fail prematurely. The gears should have no additional material on the gear teeth or on the sides of the gears.
     The seals and bearings need to be removed if the end plates need to be ground. The Oliver manual instructs one to remove the bearings with a pilot bearing puller. The bearing cage can be cut out with a torch or a very small hand grinder after the needles are removed. Be careful not to cut in to the end plates.

Assembly

     The smallest grit can reduce the life of a pump. Start by washing all the parts, including new parts, and blow dry with compressed air. When all parts are on hand to assemble, everything should be kept as clean as possible. Bearing should be pressed carefully in to the end plates. Install the bearings with the manufacturer’s numbers out. The bearings must be recessed into the plates with 3/32” clearance for the snap ring. Lube the seals and bearings with hydraulic oil and install the drive and driven gears in the front end plate making sure they turn freely.

     Remember, the splines on the drive sleeve are to the front end plate. Install the rear part and install the bolts finger tight. The dowel pins can now be driven in to the pump. Once again check to see that the gears turn freely. Tighten the bolts in an alternate pattern until all are tight to 33 to 34 ft lb. The gears must still turn freely.