105488-1121 ZEXEL 9 420 612 004 BOSCH GOVERNOR 9420612004 1054881121 1910196860

There are two operation checks that are fast and need no special equipment. One check is the PULL-DOWN RPM CHECK to see if the BrakeSaver can give full braking force. The other check is the KLUNK CHECK to see if the valve spool in the BrakeSaver control valve has free movement. These two checks give an approximate indication that the BrakeSaver has the correct operation.Pull-Down RPM Check
The engine must give rated horsepower for this test to have accuracy.1. Actuate the brakes, put the transmission in NEUTRAL and operate the engine at high idle rpm (accelerator pedal all the way down).2. Make a record of the engine rpm.3. Put the BrakeSaver control to the full ON position.4. Make a record of the engine rpm with the BrakeSaver full on.5. The engine rpm with the BrakeSaver full on must be 150 25 rpm less than the engine rpm with the BrakeSaver off. If the difference in rpm is less than 125 rpm, the BrakeSaver is not giving full braking force. If the difference in rpm is more than 175 rpm, check the air pressure to the BrakeSaver control valve. The air pressure must not be more than 345 kPa (50 psi).
Do not run the engine at high idle rpm with the BrakeSaver ON for more than 15 seconds at a time. Let the engine run a low idle with the BrakeSaver off for five minutes to keep from getting the engine cooling system too hot.
Klunk Check (check for free movement of the valve spool)
1. Run the engine until the truck air system is at its maximum pressure and then stop the engine.2. Put the BrakeSaver in the full ON position before the air pressure in the truck air system gets below 480 kPa (70 psi).3. Put the BrakeSaver in the OFF position. A noise ("klunk") must be heard at the BrakeSaver control valve as the valve spool hits the cover at the air inlet end of the control valve.4. If the noise is not heard at the BrakeSaver control valve, remove and disassemble the control valve. Inspect the valve for: a. A damaged valve body.b. Damaged or worn springs in the valve spool.c. Damaged or worn valve spool.d. Damaged or worn O-ring seals or diaphragm in the control valve.e. Closed holes (small holes to feel pressure) in the side of the valve spool.For specific problems, make reference to the PROBLEM LIST below.Problem List
1. BrakeSaver does not give full braking force with the mode selector switch in the MANUAL position.2. BrakeSaver does not give full braking force with the mode selector switch in the AUTOMATIC-MANUAL position.3. BrakeSaver Oil temperature is too high.4. BrakeSaver does not turn OFF or become empty.5. Oil leakage from the flywheel housing.6. Oil leakage from the clutch housing or transmission.
Gauge Holes For Troubleshooting
(1) Oil pressure from the BrakeSaver. (2) Oil pressure from the engine. (3) Oil pressure to the BrakeSaver. (4) Test point for BrakeSaver oil temperature. (5) Oil pressure to the engine. (6) Air pressure