SkyTrak 6036 Service Manual - Manual (Page 177)

Model 6036 S/N 9B0499 and Before 9-64
Section 9. Hydraulic System
8. Remove connecting shaft (10). Remove thrust
plate (8), seal (7) and seal (11).
9. Remove integral gear set (14). Keep these
together as they are a matched set. Be
careful not to damage the machined surfaces
of the gears.
10. Remove thrust plate (8), seal (7) and seal
(11).
11. Lift or pry off the first section gear housing
(15). Be careful not to damage machined
surfaces.
12. Remove thrust plate (8), seal (7) and seal
(11).
13. Grip the shaft end cover (16) in a vise with the
mounting face down. Remove double lip seal
(17) by inserting the special seal removal tool
(Fig. 9.39) into the notch between the double
lip seal and the shaft end cover. Tap the seal
out and discard. Remove and discard all
rubber and polymer seals.
e. Cleaning
Clean metal tandem pump components in an
approved cleaning solvent and blow dry.
f. Inspection, Repair and Replacement
1. If either a dowel (5 Fig. 9.42) or a dowel hole
is damaged, the dowel or machined casting, or
both, must be replaced. Pull defective dowels
as required.
2. Examine thrust plates (8,) and replace if
necessary. The thrust plates seal the gear
section at the sides of the gears. Wear here
will allow internal slippage, that is, oil will
bypass within the pump. A maximum 0.002"
(0.05 mm) wear is allowable. Replace thrust
plates if they are scored, eroded or pitted.
Check center of thrust plates where the gears
mesh. Erosion here indicates oil contamina-
tion. Pitted thrust plates indicate cavitation or
oil aeration. Discolored thrust plates indicate
overheating, probably due to insufficient oil.
3. Examine the drive and driven gear set (9).
Replace as a matched set if there is scoring
on the gear hubs; scoring, grooving, or burring
of the outside diameter of the teeth, or nicking,
grooving, or fretting of teeth surfaces.
4. Examine the gear housings (12 and 15) and
replace it if necessary. Wear in excess of
0.007 inch (0.18 mm) cutout necessitates
replacement of the gear housing. Place a
straightedge across bore. If you can slip a
0.007 inch (0.18 mm) feeler gauge under the
straightedge in the cutout area, replace the
gear housing. Pressure pushes the gears
against the housing on the low pressure side.
As the hubs and bushings wear, the cutout
becomes more pronounced. Excessive cutout
in a short period of time indicates excessive
pressure or oil contamination. If the relief
valve settings are within prescribed limits,
check for shock pressures or tampering.
Withdraw oil sample and check it and tank for
dirt. Where cutout is moderate, 0.007 inch
(0.18 mm) or less, gear housing is in good
condition and may be reused.
5. Examine integral gear shaft set (14). Examine
the gears as described in paragraph 3 above.
Examine all drive shafts and replace if there is
any wear detectable by touch in the seal area
or at the drive coupling. Maximum allowable
wear is 0.002 inch (0.05 mm). Wear in the
shaft seal area indicates oil contamination.
Wear or damage to splines, keys, or keyways
necessitates replacement.
6. If gears are replaced, bushings (18) must be
replaced. Bushings should fit into bore with a
heavy press fit. Inspect all bushings for
scoring or discoloration and replace if neces-
sary. Use a bushing puller (Fig. 9.38) to
remove bushings.
7. Replace all rubber and polymer seals, includ-
ing all O-rings, channel seals, shaft seals and
gasket seals.
8. Examine the plugs (6) in the shaft end and
port end covers to make sure that the plugs
are in the proper position and tight. There
should be two plugs in both the shaft end and
port end. Replace any plugs which are
damaged or cannot be tightened.
g. Assembly
1. Stone all machined surfaces with a medium
grit Carborundum stone.
2. If bushings have been removed, deburr the
bushing bores with fine emery cloth.
3. Rinse parts in an approved solvent. Air blast
all parts and wipe with a clean lint free cloth
before starting assembly.
4. Grip shaft end cover (16, Fig. 9.42) in vise with
mounting face down. If plugs (6) were re-
moved, screw new plugs in tightly. Stake plug
with prick punch at both ends of screwdriver
slot and around edges. Peen the edge of the
hole 1/32 to 1/16" (0.79 mm to 1.59 mm) with
a 1-1/2" diameter steel ball.