Dodge RAM TRUCK 1500 1995 Service Manual page 1068

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POWEi UNIT
DISASSEMBLY/INSPECTION
(1) Remove the drain plug (Fig. 9). Drain the unit.
(2) Extend the ram and piston rod completely.
Drain the remaining oil from the cylinder.
(3) Remove the cover lock nuts (Fig. 9). Remove
the cover.
(4) Inspect the casting for damage and cracks. In­
spect the seal for cuts (Fig. 9).
(5) Remove the ram and the piston. Inspect the ny­
lon sleeve, the piston, and the piston follower for ex­
cessive wear (Fig. 10).
(6) Inspect the cylinder for pitting and scoring in
the bore (Fig. 10).
(7) Inspect the ram for nicks, scratches, and corro­
sion (Fig. 10).
(8) Inspect the piston packing cup for wear (Fig. 10).
(9) Clean and inspect the base strainer.
(10) Replace all the O-ring seals during assembly.
(11) Loosen the motor bolts. Do not remove the
bolts from the motor. Retain the motor end plate dur­
ing removal. Temporarily install two nuts on the mo­
tor bolts to retain the motor intact.
Both Prestolite and American Bosch motors
are used in snow plow power units. A Prestolite
motor can be identified b y a domed top cover
and the trade name stamped on the body. Amer­
ican Bosch motors have a flat top cover and no
identifying name or marks.
(12) Remove the pump drive shaft seal.
(13) Verify the seal kit components are correct for
the unit.
(14) Dip the new seal in oil. Install it over the
pump shaft with the seal lip facing down.
(15) Position the seal in the pump housing slightly
below the boss face.
(16) Remove solenoid valve A coil from the base.
Test it for continuity. The normal coil DC resistance
is 9.0 ohms ±10%.
(17) Remove solenoid valve A cartridge. Inspect for
external damage.
(18) Remove the filters. Clean the screens with
cleaning solvent and compressed air. Discard the C D -
ring seals and the nylon retaining rings.
(19) Remove the pump housing (Fig. 9). Remove the in­
sert valve, the ball, the spring, and the. retainer from the
pump housing (Fig. 11). Inspect all the components for
damage and contamination. Discard the O-ring seals.
(20) Remove the socket-head screws. Remove the
valve block from the pump housing (Fig. 9). Discard
the O-ring seals.
(21) Remove solenoid valve B with special tool
J-25399 (Fig. 9).
(22) Remove the ball and spring from the valve
block (Fig. 9). Clean the solenoid valve. Inspect it for
external damage.
— — BUMPERS AND FRAME 13 - 15
(23) Disassemble the three-way valve (Fig. 9). Dis­
card the O-ring seal.
(24) Remove and clean solenoid valve C with spe­
cial tool J-25399 (Fig. 9). Inspect the solenoid valve
for external damage.
(25) Disassemble the four-way valve (Fig. 12). Dis­
card the O-ring seals (Fig. 12).
(26) Test solenoid valve B and C coils for electrical
continuity. The normal coil DC resistance is 3.7 ohms.
(27) Remove the pilot check valve plug, the spring
and the ball from the bottom of the valve block.
(28) Inspect the spring for damage and the ball
seat for nicks.
(29) Remove the acorn nut for access to the cross­
over valve components (Fig. 9).
(30) Remove the crossover valve components (Fig. 13).
Inspect for external damage. Discard the O-ring seals.
(31) Clean the block with compressed air to remove
all foreign material.
ASSEMBLY
Verify that all components are clean, free of foreign
material. Use replacement gaskets and seals during
assembly. Petroleum jelly should used for installing
the rubber O-ring seals.
(1) Install the crossover valve components in the
valve block with replacement O-ring seals (Fig. 13)
(2) Install the ball, spring and pressure plug with
a replacement O-ring seal in the bottom of the valve
block (Fig. 13)
(3) Assemble solenoid valve C with replacement O-
ring seals and nylon retainer rings (Fig. 12).
(4) Install solenoid valve C with Tool J-25399 (Fig. 9).
(5) Assemble solenoid valve B with replacement O-
ring seals.
(6) Install the ball, spring and solenoid valve B
with Tool J-25399 (Fig. 9).
(7) Install the valve block and the replacement O-
ring seals on the pump base.
(8) Install the retainer, the spring, the ball, the in­
sert valve and the pump housing with replacement
O-ring seals (Fig. 11). Tighten the pump housing
base nuts to 11.3 N-m (100 in. lbs.) torque.
(9) Install the filters and the plugs with replace­
ment O-ring seals (Fig. 9).
(10) Install solenoid valve A cartridge in the pump
base with replacement O-ring seals (Fig. 9).
(11) Install solenoid valve A coil (Fig. 9).
(12) Install the motor on the pump housing (Fig.
9). Engage the gear shaft tang with the notch in the
motor output shaft. Tighten the motor housing cap
screws to 5 N-m (45 in. lbs.) torque.
(13) Install the ram and piston with replacement
O-ring seals (Fig. 9).
(14) Position the cover on the reservoir. Secure it
with lock nuts (Fig. 9). Tighten the lock nuts to 11.3
N-m (100 in. lbs.) torque.