(3)The only re-working advisable is to remove burrs at the edge of the gear track and in the bearing locations,and this should be carefully effected with fine emery cloth.NOTEUnder working conditions hydraulic pressure within the pump forces the gears towards theinlet side of the body on the running track. Therefore, if the running track is past the limit forre-use, the fitting of new bearings may not improve efficiency as the new bearing will tend toprevent the gears bottoming in the running track.c.Gears.(1)Inspect the gears for scored or worn side faces or journals, damaged teeth, thread or keyway, and surfacecracks.(2)Slight wear and scoring on the journals can be erased by polishing between lathe centres using O gradeemery paper lubricated with paraffin. Slightly scored side faces may be renovated by sandwiching emerypaper between the gear face and a scrap bearing, as in Figure 4-18.(3)While servicing the drive and driven gears, particular attention should be paid to the following points.(a)Gear widths of drive and driven gears must be within 0.005mm(0.0002") of each other to ensuresatisfactory pump efficiency. (See Figure 4-18).Figure 4-18. Pump Gears4-70
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