Everything is new on the breaks side. Wheel cylinders, master cylinder, booster, abs hydraulic unit, (proportioning valve) lines so when I bleed breaks with truck off get a perfect pedal but when you turn truck on slowly goes to the floor. Please help
RESPONSE
ABS Bleeding
The 4-wheel anti-lock brake system can be bled in the conventional manner unless the Hydraulic Control Unit (HCU) has been replaced. Only perform this procedure if the HCU has been replaced.
NOTE: Brake fluid absorbs moisture from the air. Don’t leave the master cylinder or the fluid container uncovered any longer than necessary. Be careful handling the fluid — it will damage the vehicle’s paint.
- Pressure bleed the brake system.
- Connect Anti-Lock Brake Adapter T90P-50-ALA (bleeder box) and Anti-Lock Adapter T93T-50-ALA (jumper cable).
- Press down on the brake pedal and depress the VALVES button on the bleeder box (brake pedal will fall.
- Release the VALVES button and release the brake pedal.
- Repeat Steps 3 and 4 once more.
- Depress the MOTOR START button and let the pump motor run for 1 minute.
- Pressure bleed the brake system.
Check the level of the fluid often when bleeding, and refill the reservoirs as necessary. Don’t let them run dry, or you will have to repeat the process. - Have an assistant push the brake pedal down slowly through its full travel. Close the bleeder fitting and allow the pedal to slowly return to its full release position. Wait 5 seconds and repeat the procedure until no bubbles appear at the submerged end of the bleeder tube. Secure the bleeder fitting and remove the bleeder tube. Install the rubber dust cap on the bleeder fitting.
- Repeat the bleeding procedure at the left front, left rear and right front (in that order). Refill the master cylinder reservoir after each caliper has been bled, and install the master cylinder cap and gasket. When brake bleeding is completed, the fluid level should be filled to the maximum level indicated on the reservoir.
- Always make sure the disc brake pistons are returned to their normal positions by depressing the brake pedal several times until normal pedal travel is established. If the pedal feels spongy, repeat the bleeding procedure.
After finishing, there should be no feeling of sponginess in the brake pedal. If there is, either there is still air in the line, in which case the process must be repeated, or there is a leak somewhere, which, of course, must be corrected before the vehicle is moved. After all repairs and service work is finished, road test the vehicle to verify proper brake system operation.
