[4th Gen : 01-07]: How to flush brake system
#1
04-07-2017, 10:41 AM
Join Date: Jun 2008
Location: Indiana
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#2
04-07-2017, 11:10 AM
ABS or no? Procedure is different for each. Uses about 2 qts of fluid.
STANDARD PROCEDURE - BASE BRAKE BLEEDING:
NOTE: This bleeding procedure is only for the vehicle's base brakes hydraulic system. For bleeding
the antilock brakes hydraulic system, (Refer to 5 -BRAKES - ABS - STANDARD PROCEDURE)
CAUTION: Before removing the master cylinder cover, thoroughly clean the cover and master cylinder fluid reservoir to prevent dirt and other foreign matter from dropping into the master cylinder fluid reservoir.
NOTE: The following wheel sequence should be used when bleeding the brake hydraulic system.
The use of this wheel sequence will ensure adequate removal of all trapped air from the brake hydraulic system.
• Left Rear Wheel
• Right Front Wheel
• Right Rear Wheel
• Left Front Wheel
NOTE: When bleeding the brake system, some air may be trapped in the brake lines or valves far upstream, as much as ten feet from the bleeder screw. Therefore, it is essential to have a fast flow of a large volume of brake fluid when bleeding the brakes to ensure all the air gets out.
MANUAL BLEEDING PROCEDURE
NOTE: Correct manual bleeding of the brakes hydraulic system will require the aid of a helper.
NOTE: To adequately bleed the brakes using the manual bleeding procedure the rear brakes must be correctly adjusted. Prior to the manual bleeding of the brake hydraulic system, correctly adjust the
rear brakes.
(1) Pump the brake pedal three or four times and hold it down before the bleeder screw is opened.
(2) Push the brake pedal toward the floor and hold it down. Then open the left rear bleeder screw at least 1 full turn. When the bleeder screw opens the brake pedal will drop all the way to the floor.
CAUTION: Just cracking the bleeder screw often restricts fluid flow, allowing only a slow, weak fluid discharge of fluid. This practice will NOT get all the air out. Make sure the bleeder is opened at least 1 full turn when bleeding.
(3) Release the brake pedal only after the bleeder screw is closed.
(4) Repeat steps 1 through 3, four or five times, at each bleeder screw in the proper sequence. This should pass a sufficient amount of fluid to expel all the trapped air from the brake system. Be sure to monitor the fluid level in the master cylinder, so it stays at a proper level so air will not enter the brake system through the master cylinder.
(5) Check pedal travel. If pedal travel is excessive or has not been improved, enough fluid has not passed through the system to expel all the trapped air. Continue to bleed system as necessary.
(6) Perform a final adjustment of the rear brake shoes (when applicable), then test drive vehicle to be sure brakes are operating correctly and that pedal is solid.
PRESSURE BLEEDING PROCEDURE
CAUTION: Use bleeder tank Special Tool C-3496-B or equivalent with Adapter, Special Tool 6921, to pressurize the hydraulic system for bleeding. Follow pressure bleeder manufacturer's instructions for use of pressure bleeding equipment.
(1) Install the Adapter Master Cylinder Pressure Bleed Cap, Special Tool 6921 on the fluid reservoir of the master cylinder. Attach the fluid hose from the pressure bleeder to the fitting on Special Tool 6921.
(2) Attach a clear plastic hose to the bleeder screw at one wheel and feed the hose into a clear jar containing fresh brake fluid.
(3) Open the left rear wheel bleeder screw at least one full turn or more to obtain an adequate flow of
brake fluid.
CAUTION: Just cracking the bleeder screw often restricts fluid flow, allowing only a slow, weak fluid discharge of fluid. This practice will NOT get all the air out. Make sure the bleeder is opened at least 1 full turn when bleeding.
(4) After 4 to 8 ounces of brake fluid has been bled through the hydraulic system, and an air-free flow is
maintained in the hose and jar, this will indicate a good bleed of the hydraulic system has been obtained.
(5) Repeat the procedure at all the other remaining bleeder screws.
(6) Check pedal travel. If pedal travel is excessive or has not been improved, enough fluid has not passed through the system to expel all the trapped air. Be sure to monitor the fluid level in the pressure bleeder, so it stays at a proper level so air will not enter the brake system through the master cylinder.
(7) Perform a final adjustment of the rear brake shoes (when applicable), then test drive vehicle to be sure brakes are operating correctly and that pedal is solid.
STANDARD PROCEDURE - ANTILOCK BRAKE SYSTEM BLEEDING
The base brake's hydraulic system must be bled anytime air enters the hydraulic system. The ABS though, particularly the ICU (HCU), should only be bled when the HCU is replaced or removed from the vehicle. The ABS must always be bled anytime it is suspected that the HCU has ingested air. Under most circumstances that require the bleeding of the brakes hydraulic system, only the base brake hydraulic system needs to be bled. It is important to note that excessive air in the brake system will cause a soft or spongy feeling brake pedal. During the brake bleeding procedure, be sure the brake fluid level remains close to the FULL level in the master cylinder fluid reservoir. Check the fluid level periodically during the bleeding procedure and add DOT 3 brake fluid as required. The ABS must be bled as two independent braking systems. The non-ABS portion of the brake system
with ABS is to be bled the same as any non-ABS system. The ABS portion of the brake system must be bled separately. Use the following procedure to properly bleed the brake hydraulic system including the ABS.
BLEEDING
When bleeding the ABS system, the following bleeding sequence must be followed to insure complete and adequate bleeding.
(1) Make sure all hydraulic fluid lines are installed and properly torqued.
(2) Connect the DRBIIIt scan tool to the diagnostics connector. The diagnostic connector is located under the lower steering column cover to the left of the steering column.
(3) Using the DRB, check to make sure the CAB does not have any fault codes stored. If it does, clear them using the DRB.
WARNING: WHEN BLEEDING THE BRAKE SYSTEM WEAR SAFETY GLASSES. A CLEAR BLEED TUBE MUST BE ATTACHED TO THE BLEEDER SCREWS AND SUBMERGED IN A CLEAR CONTAINER FILLED PART WAY WITH CLEAN BRAKE FLUID. DIRECT THE FLOW OF BRAKE FLUID AWAY FROM YOURSELF AND THE PAINTE SURFACES OF THE VEHICLE. BRAKE FLUID AT HIGH PRESSURE MAY COME OUT OF THE BLEEDER SCREWS WHEN OPENED.
(4) Bleed the base brake system using the standard pressure or manual bleeding procedure. (Refer to 5 - BRAKES - BASE - STANDARD PROCEDURE)
(5) Using the DRB, select ANTILOCK BRAKES, followed by MISCELLANEOUS, then BLEED BRAKES. Follow the instructions displayed. When the scan tool displays TEST COMPLETED, disconnect the scan tool and proceed.
(6) Bleed the base brake system a second time. Check brake fluid level in the reservoir periodically to prevent emptying, causing air to enter the hydraulic system.
(7) Fill the master cylinder reservoir to the full level.
(8) Test drive the vehicle to be sure the brakes are operating correctly and that the brake pedal does not
feel spongy.
STANDARD PROCEDURE - BASE BRAKE BLEEDING:
NOTE: This bleeding procedure is only for the vehicle's base brakes hydraulic system. For bleeding
the antilock brakes hydraulic system, (Refer to 5 -BRAKES - ABS - STANDARD PROCEDURE)
CAUTION: Before removing the master cylinder cover, thoroughly clean the cover and master cylinder fluid reservoir to prevent dirt and other foreign matter from dropping into the master cylinder fluid reservoir.
NOTE: The following wheel sequence should be used when bleeding the brake hydraulic system.
The use of this wheel sequence will ensure adequate removal of all trapped air from the brake hydraulic system.
• Left Rear Wheel
• Right Front Wheel
• Right Rear Wheel
• Left Front Wheel
NOTE: When bleeding the brake system, some air may be trapped in the brake lines or valves far upstream, as much as ten feet from the bleeder screw. Therefore, it is essential to have a fast flow of a large volume of brake fluid when bleeding the brakes to ensure all the air gets out.
MANUAL BLEEDING PROCEDURE
NOTE: Correct manual bleeding of the brakes hydraulic system will require the aid of a helper.
NOTE: To adequately bleed the brakes using the manual bleeding procedure the rear brakes must be correctly adjusted. Prior to the manual bleeding of the brake hydraulic system, correctly adjust the
rear brakes.
(1) Pump the brake pedal three or four times and hold it down before the bleeder screw is opened.
(2) Push the brake pedal toward the floor and hold it down. Then open the left rear bleeder screw at least 1 full turn. When the bleeder screw opens the brake pedal will drop all the way to the floor.
CAUTION: Just cracking the bleeder screw often restricts fluid flow, allowing only a slow, weak fluid discharge of fluid. This practice will NOT get all the air out. Make sure the bleeder is opened at least 1 full turn when bleeding.
(3) Release the brake pedal only after the bleeder screw is closed.
(4) Repeat steps 1 through 3, four or five times, at each bleeder screw in the proper sequence. This should pass a sufficient amount of fluid to expel all the trapped air from the brake system. Be sure to monitor the fluid level in the master cylinder, so it stays at a proper level so air will not enter the brake system through the master cylinder.
(5) Check pedal travel. If pedal travel is excessive or has not been improved, enough fluid has not passed through the system to expel all the trapped air. Continue to bleed system as necessary.
(6) Perform a final adjustment of the rear brake shoes (when applicable), then test drive vehicle to be sure brakes are operating correctly and that pedal is solid.
PRESSURE BLEEDING PROCEDURE
CAUTION: Use bleeder tank Special Tool C-3496-B or equivalent with Adapter, Special Tool 6921, to pressurize the hydraulic system for bleeding. Follow pressure bleeder manufacturer's instructions for use of pressure bleeding equipment.
(1) Install the Adapter Master Cylinder Pressure Bleed Cap, Special Tool 6921 on the fluid reservoir of the master cylinder. Attach the fluid hose from the pressure bleeder to the fitting on Special Tool 6921.
(2) Attach a clear plastic hose to the bleeder screw at one wheel and feed the hose into a clear jar containing fresh brake fluid.
(3) Open the left rear wheel bleeder screw at least one full turn or more to obtain an adequate flow of
brake fluid.
CAUTION: Just cracking the bleeder screw often restricts fluid flow, allowing only a slow, weak fluid discharge of fluid. This practice will NOT get all the air out. Make sure the bleeder is opened at least 1 full turn when bleeding.
(4) After 4 to 8 ounces of brake fluid has been bled through the hydraulic system, and an air-free flow is
maintained in the hose and jar, this will indicate a good bleed of the hydraulic system has been obtained.
(5) Repeat the procedure at all the other remaining bleeder screws.
(6) Check pedal travel. If pedal travel is excessive or has not been improved, enough fluid has not passed through the system to expel all the trapped air. Be sure to monitor the fluid level in the pressure bleeder, so it stays at a proper level so air will not enter the brake system through the master cylinder.
(7) Perform a final adjustment of the rear brake shoes (when applicable), then test drive vehicle to be sure brakes are operating correctly and that pedal is solid.
STANDARD PROCEDURE - ANTILOCK BRAKE SYSTEM BLEEDING
The base brake's hydraulic system must be bled anytime air enters the hydraulic system. The ABS though, particularly the ICU (HCU), should only be bled when the HCU is replaced or removed from the vehicle. The ABS must always be bled anytime it is suspected that the HCU has ingested air. Under most circumstances that require the bleeding of the brakes hydraulic system, only the base brake hydraulic system needs to be bled. It is important to note that excessive air in the brake system will cause a soft or spongy feeling brake pedal. During the brake bleeding procedure, be sure the brake fluid level remains close to the FULL level in the master cylinder fluid reservoir. Check the fluid level periodically during the bleeding procedure and add DOT 3 brake fluid as required. The ABS must be bled as two independent braking systems. The non-ABS portion of the brake system
with ABS is to be bled the same as any non-ABS system. The ABS portion of the brake system must be bled separately. Use the following procedure to properly bleed the brake hydraulic system including the ABS.
BLEEDING
When bleeding the ABS system, the following bleeding sequence must be followed to insure complete and adequate bleeding.
(1) Make sure all hydraulic fluid lines are installed and properly torqued.
(2) Connect the DRBIIIt scan tool to the diagnostics connector. The diagnostic connector is located under the lower steering column cover to the left of the steering column.
(3) Using the DRB, check to make sure the CAB does not have any fault codes stored. If it does, clear them using the DRB.
WARNING: WHEN BLEEDING THE BRAKE SYSTEM WEAR SAFETY GLASSES. A CLEAR BLEED TUBE MUST BE ATTACHED TO THE BLEEDER SCREWS AND SUBMERGED IN A CLEAR CONTAINER FILLED PART WAY WITH CLEAN BRAKE FLUID. DIRECT THE FLOW OF BRAKE FLUID AWAY FROM YOURSELF AND THE PAINTE SURFACES OF THE VEHICLE. BRAKE FLUID AT HIGH PRESSURE MAY COME OUT OF THE BLEEDER SCREWS WHEN OPENED.
(4) Bleed the base brake system using the standard pressure or manual bleeding procedure. (Refer to 5 - BRAKES - BASE - STANDARD PROCEDURE)
(5) Using the DRB, select ANTILOCK BRAKES, followed by MISCELLANEOUS, then BLEED BRAKES. Follow the instructions displayed. When the scan tool displays TEST COMPLETED, disconnect the scan tool and proceed.
(6) Bleed the base brake system a second time. Check brake fluid level in the reservoir periodically to prevent emptying, causing air to enter the hydraulic system.
(7) Fill the master cylinder reservoir to the full level.
(8) Test drive the vehicle to be sure the brakes are operating correctly and that the brake pedal does not
feel spongy.
Last edited by jkeaton; 04-07-2017 at 11:22 AM.