Parker P1 Series - 018, 028, 045 Inspection

Parker Hannin Corporation
Hydraulic Pump and
Power Systems Division
Marysville, Ohio USA
Bulletin HY28-2665-02/SVC/EN
Medium Pressure Axial Piston Pumps
P1/PD Maintenance
37
PUMP INSPECTION PROCEDURES
COMPENSATOR INSPECTION
018, 028, 045 Pump Maintenance
Carefully clean and dry all parts prior to inspection. Refer to chart 1 for dimension-
al information regarding allowable tolerances.
1. Examine piston diameters for scratches or gouges. If any piston is severely-
damaged, note which piston bore it came out of. Extra attention should be
given to that bore in step 2. Check end play of piston shoe assembly. Check
the bottom surface of the shoes for damage. The shoe surface should be
square and at. Measure the depth of the pocket of the shoe. Shoes may be
lapped as a set if the pocket depth is within allowable limits. Conrm pocket
depth after lapping to insure it is still within limits.
2. Examine bores in cylinder for scratches Check diameter of bores in 4differ-
ent locations, including near the bottom of the barrel where the piston does
not travel. If the dimensions vary by more than 0.0102 mm (0.0004 in.)or any
dimension exceeds the allowable limit, the barrel needs to be replaced. Exam-
ine the barrel face for scratches and gouges. The barrel canbe reworked if
dimensions are with specications listed in chart 1.
3. The port plate can be lapped lightly if the face is only lightly scratched,
otherwise it should be replaced.
4. Examine the retainer plate in the area of contact with the piston shoes. Any-
marks beyond light polishing indicate that replacement is necessary. Check
the surface of the spherical area of the retainer plate and the spherical guide
ball. Inspect the back surface of the spherical guide ball where the load pins
make contact. If indentations are present replace the guide ball.
5. Examine cam on top and bottom surface. If scratches or gouges appear to
penetrate the surface treatment, the cam must be replaced.
6. The cam bearings cannot be reworked and should be replaced if worn
through the Teon surface.
7. Both the bias piston and the compensator piston should move freely in
their respective bores. The pistons and bores should be free of scratches or
gouges.
8. The seal area of the drive shaft should be smooth and not have marks due
to seal wear. Keyed shafts should be inspected for signs of brinelling and
damage to the key area. Splined shafts may have a contact wear pattern but
should not show excessive wear on the spline area.
NOTE: Spinning on shaft for P1/PD-018, 028 and 045 the cylindrical bearing
should not have any signs of roller spalling, brinelling or discoloration. The
bearing should be free to rotate without bind or rough feel.
NOTE: The compensator is supplied as an assembly. Individual parts are not
available. If there is signicant damage to any of the parts, the complete
compensator will need to be replaced.
1. Inspect the main compensator spool and the load sense spool for scratches
or other damage.
2. Inspect the springs for proper free extension length (see chart on page 30).
3. Inspect the spool bores for damage. Apply a light oil lm on the appropriate
spool and check its t in the bore. The spool should t snugly in housing and
not have any radial play.