Brake pedal squishy

DAVID614

MEMBER
2013 FORD EDGE
3.2L
6 CYL
4WD
AUTOMATIC
105,000 MILES

Just replaced booster and master cylinder. Forgot to bench bleed it but have a mighty vacuum brake bleeder that I spent several minutes on each tire then followed up with traditional pump the brake bleeder. Stiff brakes that squirt lots of fluid into bleeder reservoir upon first tire, then I finish fourth (still stiff brake) and go to turn the car on and immediately lose pressure on my pedal. What could be wrong?

1 Reply

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning,

The mighty vacuum was good for the older systems but not for the new systems. They need to be pressure bled. What that means is that you need to apply air pressure to the master cylinder through the fill cap to the system to force out all the air. You need 30-50 lbs of pressure to get all the air out of the system. Conventional bleeding is not enough pressure.

You can rent a pressure bleeder at a parts store for this procedure. The air is trapped in the ABS unit and that is why you have a bad pedal. All the air from not bleeding the master prior to installation has settled into the ABS unit.

Roy

Hydraulic Control Unit (HCU) Bleeding

NOTE: Pressure bleeding the brake system is preferred to manual bleeding.

1. Follow the pressure bleeding or manual bleeding procedure steps to bleed the system.

2. Connect the scan tool and follow the ABS Service Bleed instructions.

3. Repeat the pressure bleeding or manual bleeding procedure steps to bleed the system.

Pressure

WARNING: Do not use any fluid other than clean brake fluid meeting manufacturer's specification. Additionally, do not use brake fluid that has been previously drained. Following these instructions will help prevent system contamination, brake component damage and the risk of serious personal injury.

WARNING: Carefully read cautionary information on product label. For emergency medical information seek medical advice. In the USA or Canada on Ford/Motorcraft products call: 1-800-959-3673. For additional information, consult the product Material Safety Data Sheet (MSDS) if available. Failure to follow these instructions may result in serious personal injury.

WARNING: Do not allow the brake master cylinder to run dry during the bleeding operation. Master cylinder may be damaged if operated without fluid, resulting in degraded braking performance. Failure to follow this instruction may result in serious personal injury.

NOTICE: Do not spill brake fluid on painted or plastic surfaces or damage to the surface may occur. If brake fluid is spilled onto a painted or plastic surface, immediately wash the surface with water.

NOTE: Pressure bleeding the brake system is preferred to manual bleeding.

NOTE: The Hydraulic Control Unit (HCU) bleeding procedure must be carried out if the HCU (Hydraulic Control Unit) or any components upstream of the HCU (Hydraulic Control Unit) are installed new.

1. Clean all the dirt from around the brake fluid reservoir cap and remove the cap. Fill the brake master cylinder reservoir with clean, specified brake fluid.

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2. NOTE: Master cylinder pressure bleeder adapter tools are available from various manufacturers of pressure bleeding equipment. Follow the instructions of the manufacturer when installing the adapter.

Install the bleeder adapter to the brake master cylinder reservoir and attach the bleeder tank hose to the fitting on the adapter.

3. NOTE: Make sure the bleeder tank contains enough specified brake fluid to complete the bleeding operation.

Open the valve on the bleeder tank.

- Apply 207-345 kPa (30-50 psi) to the brake system.

4. Remove the RH rear bleeder cap and place a box-end wrench on the bleeder screw. Attach a rubber drain tube to the RH rear bleeder screw and submerge the free end of the tube in a container partially filled with clean, specified brake fluid.

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5. NOTE: Due to the complexity of the fluid path within the rear integral parking brake calipers, it is necessary to press and release the parking brake during the bleed procedure.

Loosen the RH rear bleeder screw. Leave open until clear, bubble-free brake fluid flows, then tighten the RH rear bleeder screw.

- Press and release the parking brake 5 times.

- Repeat until clear, bubble-free fluid comes out.

6. Tighten the RH rear bleeder screw to specification. Refer to Specifications.

- Remove the rubber hose and install the bleeder screw cap.

7. Repeat Steps 5 and 6 for the LH rear brake caliper.

8. Continue bleeding the front of the system, going in order from the RH front brake caliper and then to the LH front brake caliper.

- Tighten the front brake caliper bleeder screws to specification. Refer to Specifications.

9. Close the bleeder tank valve and release the pressure. Remove the tank hose from the adapter and remove the adapter. Fill the reservoir with clean, specified brake fluid and install the reservoir cap.