B42.20-0016-12
1 Bench accessories
M5 = Manometer of the bench feed circuit (0.2 bar divisions)..
M1 = M2 = M3 = M4 = Test circuit manometers, 0.2 bar divisions.
T1 to T17 = Circuit valves (taps).
V2 = V3 = Pressure regulating valves of the circuits 11 and 21 with discharge open to the atmosphere.
R25 = Feed circuit reservoir, 25-Liter capacity.
R1 = Test circuit reservoirs (1 liter).
(1) = (2) = (3) = (5) = Quick couplings available on the bench for the valve circuits.
2 Visual inspection
Check the valve for external damage.
3 Connect the valve to the bench
Assemble the valve on the bench according to the applicable diagram and connect:
Quick coupling (1) (test bench) to connection 11
Quick coupling (2) (test bench) to connection 12
Quick coupling (3) (test bench) to connection 21
Quick coupling (5) (test bench) to connection 23
Activate pressure reduction valve V1 and apply 9 bar to the bench feed circuit. Confirm the pressure on manometer M5.
Activate regulating valve V2 until the manometer M1 shows 8 bar.
Activate regulating valve V3 until the manometer M2 shows 8 bar.
Activate e deactivate the valve from 10 to 15 times to ensure the correct fitting of the components.
B42.20-0017-03
4 Test for leak-tightness
Activate valve V2 until the manometer M1 shows the pressure of 8 bar (circuit 11).
Activate valve V3 until the manometer M2 shows the pressure of 8 bar (circuit 12).
Activate the lever up to the locking position (brake applied).
Apply the foam of a neutral soap on portal 3 and check for leaks.
Fully return the lever to the running position (0°), apply the neutral soap foam on portal 3 again and check for leaks.
Activate e deactivate the lever on the interval between 0° and 73° and apply the foam of a neutral soap on the valve body to check for possible leaks.
Note: If a leak is found, disassemble the valve and replace the damaged components.
5 Test the operation
Activation angles and responses:
Install the lever angle measuring device.
Activate regulating valve V2 until the main circuit manometer M1, portal 11, shows 8 bar.
Activate regulating valve V3 until the emergency circuit manometer M2, portal 12, shows 8 bar. In this situation, the valve is in running position. All circuits will have the same pressure (8 bar).
Application of the parking brake:
Activate the lever to running position (0°) up to 3° to 4°. Within this range, the pressure on portal 23 shall fall to “zero” bar in manometer M4. This fact confirms that the emergency circuit through portal 23 is inactive.
Continuing the lever travel between 10° and 12°, the pressure on portal 21 is indicated by manometer M3 and must quickly fall from 8.1 to between 6.0 and 5.5 bar. If necessary, remove the exhaustion and adjust the values by slightly turning the valve seat (25).
Continue the lever travel and notice that between 45° and 55° the pressure on portal 21 will have been reduced to “zero” bar.
The lever must lock at the end of the travel, at 73°. The pressure on portal 21 shall remain at “zero” bar.
Releasing of the parking brake:
The lever must be unlocked at the end of the travel and shall return automatically from 73° (brake applied) to the 0° running position (released position).
Return the lever from 73° to 55°. In the interval between 55° and 45°, pressure must be applied to portal 21 and indicated in manometer M3.
Return the lever. In the interval between 12° and 10°, the pressure on portal 21 (manometer M3) shall increase from between 5.5 to 6.0 bar, to 8 bar. If necessary, adjust the values using the valve seat (washer 10).
Return the lever, in the interval between 4° and 3° the pressure in circuit 23 (manometer M4) shall rise from “zero” bar up to 8 bar. This means that the emergency circuit is already in operation. With the lever on the 0° running position the pressure will reach the maximum. In this position, manometers M1; M2; M3 and M4 must show 8 bar.
6 Pressure adjustment possibility in the range of use as auxiliary brake:
Activate and deactivate the lever in the interval between 1° and 55° in both directions, in a continuous and slow manner. The pressure on portal 21, indicated by manometer M3, shall increase or reduce gradually and proportionally to the lever angle, without steps larger than 0.4 bar.
Note: The possibility of graduation or scaling of any valve is a built-in characteristic and cannot be changed. An abnormal graduability indicates that the internal valve components are either blocked or dry. In this case, the valve needs repair. A manual parking brake valve that have been duly repaired, lubricated and smoothed, shall present a graduability of approximately 0.2 bar.
7 Remove the valve from the test bench
Release the pressure on circuits 11 and 12 through valves V2 and V3. Disconnect the test hoses.
Remove the valve from the device and close the portals with appropriate plastic plugs.