JLG 4394RT Service Manual - Manual (Page 177)

SECTION 4 - HYDRAULICS
3121249 – JLG Lift – 4-11
3. Using light clamping pressure on the ears of the
front cover, secure unit in vise with shaft side down.
Remove the cap screws (14) and washers (9).
4. Separate rear cover (6) from the body (13). The
static seal (8) may remain either with the body or the
cover. In either case, remove the static seal and dis-
card.
5. Lift out the rear bearing block (2), drive gear (12),
and driven gear (11).
6. Separate body (13) from front cover (5). Dowel pins
(7) and the front static seal (8) may remain with
either the body (13) or the front cover (5). In either
case, remove the static seal and discard.
7. The front bearing block (2) will typically remain in the
body (13). Invert the body and lift out the bearing
block.
8. Invert front cover (5) with shaft seal up. Remove the
shaft seal (1) by prying it out with a large screw-
driver.
NOTE: During disassembly, take special note of the wear
patterns on the bearing blocks (2) and body (13).
Relate these patterns to the inlet and outlet sides of
the pump. The large port ,whether in the body (13) or
the rear cover (6), corresponds to the inlet side of the
pump. The inlet side of the body can be identified by
the gear contact pattern in the gear bore. The bear-
ing block will have somewhat heavier wear patterns
on the inlet side.
Parts Inspection
1. Wash all parts and dry thoroughly.
2. Inspect front and rear bearing block. Replace if scor-
ing or uneven wear is observed.
NOTE: A somewhat heavier wear pattern is normal on the
low pressure (inlet) side of the bearing blocks (2).
However, there should be no heavy scoring in this
area.
3. Remove anti extrusion seal (4) and pressure loading
seal (3) from each bearing block and discard.
4. Inspect bushings in each bearing block (2). Replace
bearing block if bushings are heavily scored or
burned.
5. Inspect gear journals and faces. Replace if faces or
journals are scored or worn.
6. Inspect body for wear and scoring. If gear contact
wear on low pressure side (inlet) exceeds 0.005 in.
(0.127mm) depth, replace body. If the body is
usable, lightly wipe and remove burrs with suitable
de-burring tool.
Pump Reassembly
1. Place the front cover (5) on a flat plate with the steel
shaft seal bore up. Install new shaft seal (1). Press
seal until it is 0.157 in (4.0mm) below front surface.
Pack the area between the double lip of the seal with
Lubriplate or an equivalent grease.