11921 Slauson Ave.  Santa Fe Springs, CA.  90670  (800) 227-4116  FAX (888) 771-7713
37
PLATFORM RAISES SLOWLY
FLOW 
CONTROL 
VALVE
VENT/DOWN 
PORT
PRESSURE 
PORT
FIG. 37-3
1. Use voltmeter to verify power is being supplied to 
solenoid terminal “B”. Recharge the battery if volt-
meter indicates less than 12.6 volts (FIG. 37-1).
NOTE:  In most cases, you can avoid having to bleed the hydraulic system by
correctly positioning Liftgate platform before opening hydraulic lines. Refer 
to following procedure. Save time on the job and prevent accidental fl uid 
spills and hazards.
2. Check the hydraulic cylinder. With the platform on the ground, remove the breather plug  
or vent line from the vent/down port of the cylinder (FIG. 37-3). Raise the platform even 
with the bed. Allow pump motor to run two seconds more while you watch for hydraulic 
fl uid at the vent/down port. A few drops of hydraulic fl uid escaping the vent/down port is 
normal; however, if it streams from the vent/down port, piston seals are worn. Replace 
seals.
3.  Check and clean fl ow control valve in high pressure hydraulic line attached to cylinder. 
When installing fl ow control valve, make sure arrow on valve is oriented as shown 
      in FIG. 37-3.
4.  See the CHECKING HYDRAULIC FLUID procedure. If necessary, add hydraulic fl uid.
5.  Verify the pump motor is grounded to the vehicle frame.
6. Check for leaking hoses and fi ttings. Tighten or replace 
as required.
7. Check for structural damage or poor lubrication. Replace 
worn parts.
8. Check the fi lter in the pump reservoir. Replace if neces-
sary.
9.  With platform on the ground, remove the pressure 
hose  and fi tting from the pump and replace it with a 
0-4000 PSI pressure gauge. Hold the control switch in 
the “raise” position. Adjust the relief valve on the side of 
the pump until the gauge shows 3250 PSI (FIG. 37-2). 
Remove gauge and reinstall pressure hose.
TERMINAL “B”
BATTERY (+)
FIG. 37-1
Keep dirt, water and other contaminants from entering the 
hydraulic system. Before opening the hydraulic fl uid reservoir 
fi ller cap, drain plug and hydraulic lines, clean up contami-
nants that can get in the openings. Also, protect the openings 
from accidental contamination during maintenance. 
CAUTION
PRESSURE
GAUGE
RELIEF 
VALVE 
ADJUST 
SCREW
(REMOVE 
PLUG)
FIG. 37-2