Operation and maintenance manual

Section 250-0070
Braking System - Treadle Valve
SM 2165 Rev 1 11-03
8
1. Depress pedal assembly (1) as quickly as possible.
The output pressure on the circuits must reach
138 ± 6.9 bar (2 000 ± 100 lbf/in²) at port 'B1' and port
'B2' within 1 second. Measurement of time begins the
moment force is applied to move pedal (1).
2. Set the deadband by placing a 0.64 mm (0.025 in)
shim between the actuator base and the pedal return
stop. See Fig. 9.
4. Turn adjustment screw (4) down (clockwise) until it
is touching actuator cam.
5. Continue turning adjustment screw (4) clockwise
until you start to see a pressure reading on the
pressure gauge then back-off adjustment screw (4)
1/8 turn (anticlockwise).
6. Lock adjustment screw (4) with jam nut and remove
the shim stock. Apply a few drops of Loctite 290 to
adjustment screw (4) and nut.
Pedal Angle Adjustment
1. Loosen nuts at the rear of actuator cam. Do not
loosen nuts on 'U' bolts.
2. Adjust pedal assembly (1) angle by turning screws
located in the top face or ribbed side of pedal
assembly (1). Clockwise will raise the angle and
anticlockwise will lower the angle.
3. Adjust the two screws evenly. When the desired
pedal angle is achieved, apply Loctite 243 on screws.
4. While holding the pedal down, retighten the rear
capscrews and nuts.
INSTALLATION
Note: Tighten all fasteners to standard torques listed
in Section 300-0080, STANDARD BOLT AND NUT
TORQUE SPECIFICATIONS.
Note: Tighten all hydraulic lines fitted with ORFS
connections, as described in Section 250-0000,
BRAKING SYSTEM SCHEMATIC. Renew all 'O' rings
where used.
1. Position treadle valve assembly on service access
panel and secure with mounting hardware.
2. Secure service access panel to cab floor using bolts
and lockwashers as removed at 'Removal'.
3. Remove blanking caps and connect hydraulic lines
FINAL ASSEMBLY
Numbers in parentheses refer to Fig. 1.
1. Remove pivot pin (2) from actuator base (3).
2. Install boot (5) over lip of pilot valve body (8) and
over head of adjusting bolt (4). Apply a light coating of
Loctite Activator 710 between head of adjusting bolt (4)
and boot (5). Apply Loctite 410 adhesive to boot (5)
and head of adjusting bolt (4).
3. Insert pivot pin (2) through the hole in actuator base
(3), through the holes in 'U' bolts, and through the pivot
pin hole in the other side of actuator base (3). As pivot
pin (2) is being inserted, install pedal return springs.
4. Centre pivot pin (2) and secure with nuts and
washers on 'U' bolts. Tighten nuts to a torque of
16 - 17 Nm (140 - 150 lbf in).
5. Install pedal assembly (1) on actuator cam and
secure with capscrews, washers and nuts.
6. Install deadband adjustment screw. Thread the
screw into actuator cam until the screw contacts the
flanged adjusting screw (4).
PROXIMITY SWITCH INSTALLATION AND
ADJUSTMENT
Numbers in parentheses refer to Fig. 1.
1. Install proximity switch (28) into the actuator base
(3) until switch is flush to 0.125" (3.18mm) above the
boss on the actuator base (3).
2. Lock the proximity switch into this position with the
lower jam nut.
3. Install adjusting screw and jam nut into the pedal.
4. Thread the adjusting screw into the pedal until the
switch activates. Thread screw into the pedal 1/4 to 1/2
turn more.
5. Slowly apply pedal and note the pressure at which
the switch 'trips'. Readjust the switch to trip at 2.5 lbf/
in² (0.17 bar). Threading the set screw 'in' will raise the
'trip' point; backing the set screw 'out' will lower the 'trip'
point. Secure the set screw with the jam nut once the
proper setting is achieved.
ADDITIONAL TESTING AND ADJUSTMENT
Numbers in parentheses refer to Fig. 1.