Operation and maintenance manual

Section 250-0070
Braking System - Treadle Valve
SM 2165 Rev 1 11-03
10
9. Slacken adjusting screw (4) in valve body.
10. Install pivot pin (2) in actuator base (3) and by
taking a screw driver or pry bar and placing it under
pivot pin (2) and on top of adjusting screw (4), you will
be able to actuate each circuit individually.
11. Start engine to ensure full hydraulic pressure.
12. Test front 'B1' and rear 'B2' brake circuit actuating
pressures at remote diagnostic test points (at the rear
LH side of the tractor frame) and adjust if necessary.
Pressures should be 138 ± 6.9 bar (2 000 ± 100 lbf/in²).
Note: Turning adjustment screw (4) up (anticlockwise)
will increase the pressure while turning it down
(clockwise) will decrease the pressure. Fine
adjustment will require only turning the collar in 1/8
turn increments.
14. When pressure is set correctly, apply Loctite 290
to the threads of adjustment screw (4). Leave valve for
a minimum of two minutes to allow Loctite to cure.
Note: Use a syringe to apply Loctite to threads of
screw. Do not allow Loctite to spill over onto outer
diameter of piston. If Loctite is allowed to set up
between piston and piston guide it can result in a stuck
valve.
15. Shut down the engine.
16. Remove pivot pin (2) from actuator base (3).
emergency control.
10. Shut off engine and check hydraulic tank oil level.
Replenish as necessary.
11. Position floor mat on cab floor and ensure that the
pedal assembly is free to operate.
SERVICE
Numbers in parentheses refer to Fig. 1.
Brake Actuating Pressure
Note: Test front 'B1' and rear 'B2' brake circuit
actuating pressures at remote diagnostic test points (at
the rear LH side of the tractor frame) and adjust if
necessary.
1. Connect a hydraulic gauge capable of recording a
pressure of 0 - 207 bar (0 - 3 000 lbf/in²) to remote
diagnostic pressure point for front 'B1' brake pressure.
2. Start engine and bring hydraulic oil temperature to
operating temperature.
3. Actuate treadle valve fully and check reading on
pressure gauge. Pressure reading should be
138 ± 6.9 bar (2 000 ± 100 lbf/in²).
4. Repeat steps 1 through 3 at remote diagnostic
pressure point for rear 'B2' brake pressure.
Note: Actuating pressure for the front and rear brake
circuits is 138 ± 6.9 bar (2 000 ± 100 lbf/in²), however,
system pressure is 170 bar (2 465 lbf/in²) and can only
be checked at the pressure check point in the manifold
valve. Refer to Section 250-0050, BRAKE MANIFOLD
VALVE.
Note: If the pressures to the brake circuits have been
determined as low or high, the pressures can be raised
or lowered by an in service (in situ) adjustment.
5. Remove pedal assembly (1) from actuator cam by
loosening two capscrews at the pedal heel. Note that
capscrews need not be removed.
6. Loosen but do not remove nuts from 'U' bolts
securing actuator pivot pin (2).
7. Remove pivot pin (2) from actuator base (3) with a
punch and hammer. Remove actuator cam assembly.
8. Remove boot (5) from valve body.
SM - 1239
Fig. 9 - Deadband Adjustment
Actuator Base
Return Stop
Shim Stock
0.64 mm
(0.025 in)