Maintenance
Model 3410 Installation, Operation, and Maintenance Manual
64
Shaft sleeve
The sleeve (126) surface in the stuffing box area must be smooth and free of grooves. If there
are grooves, replace the shaft sleeve. The O-ring groove in the end of the sleeve nut must be in
good condition. The impeller end of the sleeve must be in good condition to ensure that the
gasket (428) will seal properly. The original diametric clearance between the shaft sleeve and
the stuffing box bushing is 0.030–0.034" (0.76–0.86 mm). If this clearance has increased to
more than 0.050–0.060" (1.27–1.5 mm), then the sleeve, and possibly the stuffing box bushing,
must be replaced.
Bearings
Check ball bearings (112 and 168) for visible wear. Slowly turn the races and look for pits or
worn areas on the balls or raceways.
Hold the inner race and spin the outer race. If there are rasping noises or the bearing catches
or binds, then replace the bearing. If any wear on the race is apparent, then replace the
bearing.
Replace ball bearings that are worn, loose, rough, or noisy when rotated.
Seals
Check the seals (332 and 333) for wear, cracks, cuts, deformities, and signs of excessive
leakage. Check the thrust-bearing end cover (109A) for signs of leakage and damage. Check
the grease fittings (113) or oil breathers (113A) (oil option) for serviceability and replace as
required.
General
Clean all parts before reassembly. This is especially important at O-ring grooves, gasket
surfaces, mating surfaces, and bearing areas. Check that threads on dowels, screws, nuts,
studs, and all gasket surfaces are in good condition. Make sure the anti-rotation pins (445A)
are firmly pressed into the wear rings (103).
Refer to
Bearing maintenance
(page 52) for specific instructions on cleaning bearings.
Replace impeller wear rings
1. Remove the old rings:
a) Remove the three setscrews (320).
b) Pull the ring (142) off the impeller hub.
2. Clean the hub and press on a new ring (142).
3. Drill and tap three holes 120° (1,600 mils) apart with a 7/32-in. drill and a 1/4-in. 20NC tap
on each ring.
4. Insert the setscrews.
Make sure to use 5/16 in. x 1/4 in. cup point safety setscrews.
5. Tighten the screws and lightly upset the threads. Do not use the existing holes.