SUBSECTION 5B
PUMPS
GENERAL
SEAL REPLACEMENT
This subsection contains the information necessary to re-
To replace the pump seal only, proceed as follows (see
move, disassemble, repair, assemble, and install the pumps
Figure 58-1):
used in the hydraulic control system.
1. Remove the four capscrews that attach the mounting
TROUBLESHOOTING
flange to the body.
Table 5B-1 lists some of the difficulties which may be ex-
2. Lightly tap the mounting flange clear of the two hollow
perienced with gear type hydraulic pumps. The table lists
dowels in the pump body and slide it squarely off the shaft.
the possible causes and possible remedies for the problems
3. Clamp the mounting flange securely in a soft jawed vise
iisted. This guide should be helpful in diagnosing pump
and drive the seal out with a drift. Take care that the drift
problems.
does not damage the shaft bore.
PUMP (37Z317)
4. Ensure that the seal housing in the mounting flange is
DESCRIPTION
clean and free of burrs.
One, fixed displacement, single gear type pump is used to
5. Pack the seal with a high melting point, mineral base
provide hydraulic pressure for the control system on this
grease.
machine. The pump is flanged mounted on the accessory
drive of the engine and driven by the camshaft.
6. Press the seal into the full depth of the recessed bore,
with the spring facing the inside of the mounting flange.
The pump consists of four main components: the end cover,
7. Fit the mounting flange squarely on the shaft, start the
bushing assembly, gear assembly, and mounting flange.
four capscrews, and tighten them in a diagonal pattern to a
These parts are held together by four capscrews that thread
into the mounting flange.
8. Install the pump as described under the heading IN-
The bushing gear assembly is pressure loaded against the
STALLATION at the end of this subsection.
end cover and the bushings are pressure balanced to
prevent tilt. These features ensure that internal leakage is
OVERHAUL
kept to a minimum, enabling the pump to operate at high
GENERAL. Disassembly should only be attempted on a
efficiency. The condition of the bushing faces adjacent to
bench in as clean an area as possible. The workbench, the
the gears is an important factor in maintaining this ef-
mechanic's hands, and tools must be clean and the disas-
ficiency and, during any disassembly or assembly oper-
sembled pump must be protected from airborne dust. Dur-
ations, the bushings must be handled carefully to prevent
ing disassembly, pay particular attention to the identifica-
damage. It is essential that the pump is operated only in a
tion of the parts in order that thepumpcan be properly
clean system. Any foreign matter in the oil will score the
assembled.
bushing faces, and this will lead to shortened service life
and eventual failure.
DISASSEMBLY. To disassemble the pump, proceed as fol-
REMOVAL
To remove the control pump mounted on the engine, pro-
1. Remove the end cover by removing the four capscrews
ceed as follows:
that attach it to the mounting flange. Remove O-ring (04)
1. Remove all dirt from the pump and connections with a
from the body of the pump.
cleaning solvent.
2. Remove the hydraulic hose connections from the pump.
NOTE
3. Plug the ports of the pump and cap the lines to prevent
Lightly mark and cover, body and mounting flange
the entry of dirt into the system.
(03, 10 and 13) to ensure assembly in the correct
relationship and take note of the direction of rotation
4. Remove the mounting bolts and pull the pump away
of the pump (counterclockwise).
from the engine.
5B-1