DRESSTA TD-25M EXTRA, Service Manual

Page: 382 / 595

SECTION 10A
PUMPS
Page 16
TD-25M EXTRA DRESSTA
EQUIPMENT PUMP
8. INSPECTION AND REPAIR (Refer to Fig. 10A.7)
NOTE: All parts must be thoroughly cleaned and kept clean during inspection and assembly. The
close tolerance of the parts makes this requirement very important. Clean all removed parts using
a commercial solvent that is compatible with the system oil. Compressed air may be used in
cleaning but it must be filtered to remove water and contamination.
1. Discard the shaft seals (36), seal rings (5 and 28), O-rings (4, 6 and 27, 29 and 40, 49),
back-up rings (3 and 30), wear plates (46, 48) and seal packs (8 and 21) subassemblies. Use
a new seal kit for reassembly. Wash the metal parts, blow them dry with air and place on
a clean surface for inspection.
2. Check the pumping cartridges wear surfaces for pickup, scoring and excessive wear. Slight
heat discoloration of the flex side plates (9 and 22) bronze surface is normal. Score marks
deeper than 0.025 [mm] and scratches deeper than 0.05 [mm] indicate a new part is needed.
Slight scoring and/or scratches can be removed with an oiled “Arkansas” stone.
NOTE: DO NOT use a dry stone on the bronze surface or scratches will result.
3. Inspect both sides of each vane and insert in order. If pickup, heavy wear or scoring is found,
inspect the appropriate rotors (10, 23 and 41) slot. Replace scored parts.
4. Inspect rotor rings (12, 25 and 43) for vane chatter marks, wear and/or scratches. Replace if
scoring is evident.
NOTE: Replacement rotor rings (12, 25 and 43) width must be identical to the ring being replaced
or reduced life and/or output flow will result. The minimum rotor ring (12, 25 or 43) to rotor (10, 23
or 41) clearance limits is 0.03 [mm].
NOTE: All pumping cartridge (A, B and C) parts must be free of burrs. Stone the mating surfaces
of each part with an oiled “Arkansas” stone prior to assembly.
NOTE: Pre-assembled replacement cartridge kits are available. If the old cartridge is worn
extensively, a new kit should be used.
5. Vane and rotors (10, 23 and 41) wear can be checked by inserting the vane in the rotor slot
and checking for excessive play. Replace rotor (10, 23 or 41) and vane kit (11, 24 or 42) if wear
is evident.
6. Rotate ball bearing (33) while applying pressure to check for wear, looseness and pitted or
cracked races.
7. Inspect seal and bushing mating surfaces on drive shaft (34) for scoring or wear. Replace the
shaft if marks cannot be removed by light polishing.