Gear Pump; Disassembly - JLG 1850SJ Service And Maintenance Manual

5.9 GEAR PUMP

Disassembly

Prior to proceeding it may be necessary to prepare some sub-
assemblies separately.
The details for preparing each subassembly are given in the
following section.
Also, some general recommendations are given below.
CLEANLINESS
Cleanliness is a primary factor for reliable pump performance.
Wash the outside of the pump thoroughly before disassembly
and all pieces prior to assembly. Cleaning parts with clean
shop solvent and air drying is usually adequate.
LUBRICATION OF MOVING PARTS
During assembly, it is imperative to provide lubrication with
clean hydraulic oil to all the running parts of the pump.
It is also necessary to coat the seals with grease. The absence
of lubrication during assembly can cause the unit to seize after
a few minutes of running.
CARE OF SURFACE TREATMENT
Be careful when handling all the internal surfaces, especially
bearings, gears, and body faces. Do not touch or score them
with metal tools or cutting edges.
MARKING THE PARTS
Mark the parts before completely disassembling a pump. The
marks allow components to be reassembled in the same rela-
tive position. This action should be applied to the body, bear-
ings, and gears. Scribing, bluing, or using a felt tip pen to mark
the outside of the body on the inlet side is suggested to indi-
cate the relative position of the front flange and the rear cover
to the body. Mark the bearing blocks also on the inlet side and
the gears position relative to each other. DO NOT scribe inter-
nal surfaces.
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SECTION 5 - BASIC HYDRAULIC INFORMATION & HYDRAULIC SCHEMATICS
NOTE: Clamping the pump on the body is not recommended
PROCEDURE
1. Clamp the unit.
Clamp the unit in a vice from the flange side.
Make sure the vice jaws are clean and have smooth sur-
faces to prevent damage to the pump.
because serious damage to the surfaces, on which the
ports are located, may occur.
2. Remove capscrews. (Except Units with 03 Flange).
Use a 17 mm socket wrench and loosen the four cap-
screws on the cover. Next completely unscrew the cap-
screws and remove them.
Inspect the threads of the capscrews for damage.
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