A polished pattern on the cover surface from rotation of the rotor (18) is normal.
Discoloration would indicate excess fluid temperature, thermal shock or excess speed. Under
these conditions make a very close inspection of end cover, rotor set, and wear plate.
Remove spacer (22). Inspect it for badly burned or nicked ends.
Remove rotor set (16) retaining it in its assembled form, if possible. Inspect the rotor set in its assembled form
for nicks, scoring or spalling, on any surface and broken or worn rotor splines. If any component of the rotor set
requires replacement, the complete rotor set must be replaced as a matched set.
Place rotor set (16) on a flat surface and center rotor (18) in stator (19) such that two rotor lobes (180° apart) and
a roller vane (17) centerline are on the same stator centerline. Check the rotor lobe to roller vane clearance with
a feeler gage at this common centerline. If there is more than .005 inch (0.13 mm) of clearance, replace rotor
Remove wear plate (20) and seal rings (21). Inspect the wear plate for cracks, brinelling, or scoring. Discard
seal rings (21).
Remove drive link (23) from commutator (24) and coupling shaft (25). Inspect drive link (23) for cracks and for
worn or damaged splines. No noticeable play should be noted between mating spline parts.
Remove commutator (24) by inserting two fingers into its center cavity and lifting. Inspect commutator for
cracks, burrs, wear, scoring, spalling, or brinelling. If these conditions exist, the commutator and housing (28)
must be replaced as a matched set. Inspect drive pin (26) but do not remove unless damaged.
Insert the drive link (23) into mesh with coupling shaft (25) and exert a downward force on it with the palm of one
hand while pulling down and rotating the coupling shaft with the other hand. If a roughness is felt or heard, the
thrust bearing (32) and thrust washers (31) will need replacement.
Remove coupling shaft (11) by pushing on the output end. Inspect shaft bearing and seal surfaces for spalling,
nicks, grooves, severe wear or corrosion and discoloration. If seal area wear exceeds .020 inch diametrically,
replace shaft. Inspect for damaged or worn splines, drive pin slot and keyway. Replace coupling shaft if any of
these conditions exist.
If commutator (24) was discarded in step m., above, disassembly is complete at this point.
Otherwise, proceed with disassembly.
Remove housing (28) from vise and place on a clean flat work surface with wearplate end down. Pry out and
discard the seals (20) and (33), using a dull-edged screwdriver. Be careful not to damage other components
during this process.