A. Test ABS For Proper Operation
1. Connect the DRB Scan Tool to the Data Link Connector (DLC). Be sure to use the appropriate connecting cables for the DRB Scan Tool (II or III) that you are using. Be sure that the DRB contains the latest software and a Super Cartridge or Supercard if necessary.2. With the DRB Scan Tool, read, record and then erase all Bendix ABS Diagnostic Trouble Codes (DTC's).
NOTE:
The ignition key must be turned to the OFF position after erasing DTC's to ensure that all DTC's are properly erased inside the Controller - Antilock Brake (CAB).
3. With the ignition key in the ON position, monitor the DTC display for four minutes.
^ If any DTC's are displayed, they must be diagnosed and repaired in the order that they are listed on page 221 of the Bendix Antilock 9 & 10 Service and Diagnostic Procedures Manual (81-699-96086).
^ If no DTC's are displayed, continue with Step 4.
4. With the ignition key in the OFF position, pump the brake pedal a minimum of 40 times using about 50 lbs (222 N) of pedal force. A noticeable change in the pedal feel will occur when the accumulators are discharged.
WARNING:
Brake system is under extreme pressure. The Hydraulic Control Unit (HCU) may be charged with hydraulic pressure up to 2200 psi. Failure to de-pressurize the accumulators could result in personal injury and/or damage to painted surfaces. Wear safety goggles when disconnecting system fluid lines.
5. When a definite increase in pedal pressure is felt, pump the pedal a few additional times to ensure removal of all hydraulic pressure from the brake system.
6. Install the ABS internal leakage test fixture (Special Tool # 6997) per the following procedure:
A. Remove the complete air cleaner assembly.
B. Locate the high pressure brake fluid hose going from the HCU to the pump/motor (Figure 1). Remove the high pressure hose tube nut from the fitting on the HCU.
NOTE:
For BB vehicles, remove the hose retainer in order to move the hoses.
C. Install the test fixture in-line with the high pressure hose (Figures 2 & 3). Screw male end of test fixture into high pressure fitting on HCU and torque to 145 in-lbs (16 N.m).
D. Install high pressure brake fluid hose into test fixture and torque to 145 in-lbs (16 N.m).
E. Disconnect the upper (black) HCU 10-way wiring harness connector (Figure 4) and connect it to the test fixture.
F. Attach the test fixture ground clip to the negative battery terminal.
WARNING:
Connection of test fixture wire harness as described in Steps E and F above, is required prior to start of test or pump/motor damage will occur.
7. Open the shut-off valve on the test fixture.
8. Turn the ignition key to the RUN position.
9. Allow accumulator pressure to build to its highest steady state value or until the pump shuts off.
10. Close the test fixture shut off valve within 2 seconds of pump shutoff or after reaching a steady state pressure with the pump still running, then start a timer and record both pressure gauge readings.
^ If the pump shut off and the pump/motor pressure is 1800-2200 psi, continue with STEP 11.
^ If the pump did not shut off initially but did shut off after the test fixture valve was closed, continue with STEP 11.
^ If the pump continues to run after the test fixture valve is closed and the steady state pressure is LESS THAN 2200 psi, inspect the low pressure hose and pump supply filter for restriction. A supply filter restriction can be determined by noting inadequate fluid flow from the supply filter when the pump/motor supply (low pressure) hose is disconnected at the pump/motor side of the pump supply filter. If no restriction is found, replace the pump/motor assembly per the instructions in Section C.
^ If the pump continues to run after the test fixture valve is closed and the steady state pressure is GREATER THAN 2200 psi:
WARNING:
Turn the ignition key off if pressure exceeds 2500 psi. Damage to pump/motor components will occur at pressures greater than 2500 psi.
Disconnect the 10-way connector from the test fixture.
If the pump continues to run, continue with Diagnostic Test # 25 in the Bendix Antilock 9 & 10 Service and Diagnostic Procedures Manual (81-699-96086).
If the pump stops, replace the test fixture pressure switch (PN 4485632) and begin the diagnostic test again. With the ignition key in the Off position, open the test fixture shut-off valve. Pump the brake pedal a minimum of 40 times using approximately 50 lbs (222 N) of pedal force and continue with Step 8.
11. Record the pump/motor side and HCU side pressure readings 120 seconds after closing the test fixture valve and compare with the initial readings.
^ If the pressure readings on both sides dropped less than 200 psi, continue with Step 12.
^ If the HCU side reading dropped more than 200 P51, replace the master cylinder actuator piston assemblies per the instructions in Section B.
^ If the pump/motor side reading dropped more than 200 psi or if the pump restarted within the 120 seconds, replace the pump/motor assembly per the instructions in Section C.
NOTE:
Both of the above repairs may be required.
12. With the ignition key in the Off position, open the test fixture shut-off valve. Pump the brake pedal a minimum of 40 times using approximately 50 lbs (222 N) of pedal force.
13. Turn the ignition key to the RUN position.
14. Allow accumulator pressure to build to its highest steady state value or until the pump shuts off.
15. Close the test fixture shut off valve within 2 seconds of pump shutoff or after reaching a steady state pressure with the pump still running, then start a timer and record both pressure gauge readings.
^ If the pump shut off and the pump/motor pressure is 1800-2200 psi, continue with STEP 16.
^ If the pump did not shut off initially but did shut off after the test fixture valve was closed, continue with STEP 16.
^ If the pump continues to run after the test fixture valve is closed and the steady state pressure is LESS THAN 2200 psi, inspect the low pressure hose and pump supply filter for restriction. A supply filter restriction can be determined by noting inadequate fluid flow from the supply filter when the pump/motor supply (low pressure) hose is disconnected at the pump/motor side of the pump supply filter. If no restriction is found, replace the pump/motor assembly per the instructions in Section C.
^ If the pump continues to run after the test fixture valve is closed and the steady state pressure is GREATER THAN 2200 psi:
WARNING:
Turn the ignition key off if pressure exceeds 2500 psi. Damage to pump/motor components will occur at pressures greater than 2500 psi.
Disconnect the 10-way connector from the test fixture.
If the pump continues to run, continue with Diagnostic Test # 25 in the Bendix Antilock 9 & 10 Service and Diagnostic Procedures Manual (81-699-96086).
If the pump stops, replace the test fixture pressure switch (PN 4485632) and begin the diagnostic test again. With the ignition key in the Off position, open the test fixture shut-off valve. Pump the brake pedal a minimum of 40 times using approximately 50 lbs (222 N) of pedal force and continue with Step 8.
16. Record the pump/motor side and HCU side pressure readings 120 seconds after closing the test fixture valve and compare with the initial readings.
^ If the pressure readings on both sides dropped less than 200 psi, continue with Step 17.
^ If the HCU side reading dropped more than 200 psi, replace the master cylinder actuator piston assemblies per the instructions in Section B.
^ If the pump/motor side reading dropped more than 200 psi or if the pump restarted within the 120 seconds, replace the pump/motor assembly per the instructions in Section C.
NOTE:
Both of the above repairs may be required.
17. With the ignition key in the OFF position, open the test fixture valve and then pump the brake pedal a minimum of 40 times. A noticeable change in the pedal feel will occur when the accumulators are discharged.
WARNING:
Brake system is under extreme pressure. The hydraulic control unit (HCU) may be charged with hydraulic pressure up to 2200 psi. Failure to de-pressurize the accumulators could result in personal injury and/or damage to painted surfaces. Wear safety goggles when disconnecting system fluid lines.
18. When a definite increase in pedal pressure is felt, pump the pedal a few additional times to ensure removal of all hydraulic pressure from the brake system.
19. Remove the ABS internal leakage test fixture (Special Tool # 6997).
A. Disconnect 10-way wiring harness connector from the test fixture (Figure 4) and connect it to the HCU.
B. Remove the high pressure brake fluid hose from the test fixture.
C. Remove the test fixture from the high pressure adapter on the HCU.
D. Install the high pressure hose tube nut on the fitting on the HCU and torque to 145 in-lbs (16 N.m).
E. Install the complete air cleaner assembly.
NOTE:
For BB vehicles, install the hose retainer.
20. Turn the ignition to the RUN position to energize the pump/motor and pressurize the hydraulic system. Check for leakage at the HCU.
21. With the ignition key in the OFF position, pump the brake pedal a minimum of 40 times. A noticeable change in the pedal feel will occur when the accumulators are discharged.
WARNING:
Brake system is under extreme pressure. The hydraulic control unit (HCU) may be charged with hydraulic pressure up to 2200 psi. Failure to de-pressurize the accumulators could result in personal injury and/or damage to painted surfaces. Wear safety goggles when disconnecting system fluid lines.
22. Check the brake fluid level in the HCU reservoir and adjust as necessary.
23. No further action is necessary, return the vehicle to the customer.