GMC 4000 Series Service Manual page 37

Sec. 1
Page 30
GENERAL MAINTENANCE
NOTE: Ratchet pawl spring removed in above view
1 Coil Term inals
2 Solenoid Plunger
3 Actuator Plate Tang
4 Cam Follower Upper Pin
5 Ratchet Pawl
6 Cam Follower Lower Pin
Bench Check
1. Manually actuate the solenoid plunger and
check for binding condition.
2. Check relay coil as follows: Connect 12
volt supply to washer terminals (fig. 17). Observe
if solenoid plunger pulls in. Failure of solenoid
plunger to pull in indicates an open solenoid coil
or poor solder connections.
3. If solenoid plunger pulls in correctly, man­
ually actuate the cam follower lower pin and ob­
serve if pump piston and actuator plate operate
freely. Locate and correct cause if binding occurs.
4. Attach a hose to the large or intake pipe.
You should be able to blow, but not draw, through
intake pipe (fig. 18).
5. Attach a hose individually to each of the
small exhaust pipes. You should be able to draw,
but not blow, through them. If any of the valves
allow air to pass in both directions, the valve a s­
sembly is defective and must be replaced.
PUMP DISASSEMBLY AND ASSEMBLY
(Refer to Fig. 19)
1. Remove washer pump cover.
2. Remove ratchet dog retaining screw. Hold
G M C S E R V I C E M A N U A L
7 Ratchet Wheel
8 Valve A ssy. Mtg. Screws
9 Valve Assem bly
10 Ratchet Dog
11 Dog Retaining Screw
Figure 19— W asher Hump M echanism
spring loaded solenoid plunger in position and
carefully lift the solenoid assembly and ratchet
dog off the frame of the pump.
ratchet pawl retaining ring and slide ratchet pawl
off cam follower shaft.
groove and slide ratchet wheel off shaft.
housing grooves clear frame. Remove actuator
plate from ratchet wheel and cam follower shafts.
to pump housing. Separate valve assembly from
pump housing.
moving pipe assembly from pump housing.
tween housing and valve plate is properly positioned
in the housing and valve plate grooves. Also, be
sure triple O-ring is properly installed between
valve body and pipe assembly. Hose connections
on pipe assembly should be pointed in same direc­
tion as original position.
12 Solenoid Coil Assem bly
13 Pivot Pin
14 Piston Actuator Plate
15 Ratchet Wheel Spring
16 Ratchet Pawl Spring
3. Disconnect ratchet pawl spring. Remove
4. Move ratchet wheel spring out of shaft
5. Pull pump housing away from frame until
6. Remove screws that attach valve assembly
NOTE: Observe direction of pipes before re­
7. To assem ble, reverse "Removal"procedure
NOTE: During reassembly, be sure gasket be­