EATON
PVM Piston Pump Service Manual E-PUIO-II001-E4 December 2017
40
Inspection
Before inspection of parts, clean with a solvent that is com-
patible with system fluid.
Rotating Group Parts
1. Inspect cylinder block face for wear, scratches, and/or
erosion. If cylinder block condition is questionable, replace
the entire rotating group.
2. Remove the pistons, shoe retainer, and pivot from piston
block. The piston block assembly doesn’t need to be
disassembled unless the internal pins or spring are
damaged.
3. Check each cylinder block bore for excessive wear. Use
the piston and shoe S/A (37) for this purpose. The pistons
should be a very close fit and slide in and out of the
cylinder block bores. NO BINDING CAN BE TOLERATED.
If binding occurs, clean the cylinder block and pistons.
Lubricate the cylinder block bores with clean fluid and try
again. Even minor contamination of the fluid may cause a
piston to freeze up in a cylinder bore.
4. Inspect each of the nine piston and shoe subassemblies
(31) for a maximum end play of 0.005 inch between the
piston and shoe. Also check the face dimension of each
shoe. The face dimension must be within 0.001 inch.
5. Inspect shoe retainer and pivot for wear and/or scratches.
If condition is questionable, replace entire rotating group.
Piston S/A Tolerances
This dimension must be Maintained on all nine shoes within
0.001 inch.
Shoe face rides on swash plate. Shoe must swivel smoothly
on ball. End play must not exceed 0.005 inch.
Note: Do not lap the face of piston block assembly
Inspection, Repair & Part
Replacement