Upright SL20 Series, Service & Parts Manual

Page: 32 / 104

Page 3-10
Maintenance - 3.11 - Setting Hydraulic Pressures
SL20
S
TEERING
R
ELIEF
V
ALVE
1. Operate the work platform for 10-15 minutes to bring the hydraulic oil up to normal operating
temperature.
2. Install gauge in pressure gauge port.
3. Loosen locknut or remove cover on the steering relief valve and turn adjusting screw coun-
terclockwise two full turns.
4. While one person holds the steering switch to steer the wheels fully to the left, slowly turn
the steering relief valve adjusting screw clockwise to increase the pressure until the gauge
reads 104 bar (1500 psi).
5. Tighten locknut or replace main relief valve cover and torque to 8 Nm (6 Ft/Lbs).
6. Remove gauge and replace cap.
L
IFT
R
ELIEF
V
ALVE
1. Operate the machine 10-15 minutes to warm the oil.
2. Loosen the locknut or remove the cover on the lift relief valve and turn the adjusting screw
counterclockwise two full turns.
3. Place the maximum rated load (see “Specifications”, page 2-10) on the platform.
4. Turn the chassis lift switch to LIFT position and hold it there.
5. Slowly turn the lift relief valve adjusting screw clockwise to increase the pressure until the
platform just begins to rise. The pressure should be approximately 138 bar (2000 psi)
6. Release the chassis lift switch. Tighten locknut or replace lift relief valve cover.
O
VERCENTER
V
ALVE
1. Operate the work platform for 10-15 minutes to bring the hydraulic oil up to normal operating
temperature.
2. Remove pressure gauge port cap and install the pressure gauge assembly.
3. Disconnect proximity switch.
4. Lift work platform and block front wheels off ground.
5. Loosen the locknut on overcenter valve.
6. With the chassis key switch on DECK and the drive/lift switch in DRIVE, depress the inter-
lock lever and slowly pull the control lever to REVERSE to drive the wheels.
7. Adjust the overcenter valve by turning the adjustment screw until the pressure gauge indi-
cates 55 to 69 bar (800 to 1000 psi).
8. Tighten locknut on valve to 8 Nm (6 Ft/Lbs).
9. Check the setting by slowly moving the control lever FORWARD, then REVERSE checking
the gauge to ensure pressures are properly set. Readjust as needed.
10. Remove block and lower work platform to ground.
11. Reconnect the proximity switch.
12. Remove the gauge from the gauge port and reinstall cap.
13. Check for proper operation of the drive system and brake.