Brake Bleeding

When any part of the hydraulic system has been disconnected for service, air may enter system and cause spongy pedal action. Bleed the hydraulic system after it has been opened to make sure all air is expelled.
 

Brake Master Cylinder Bleeding

When a new brake master cylinder (2140) has been installed or the brake system emptied or partially emptied, fluid may not flow from the bleeder screws during normal bleeding. It may be necessary to prime system using the following procedure.

1. Use tubing wrench to remove the brake lines from brake master cylinder.
 
2. Install short brake lines in brake master cylinder and position them so they point back into reservoir and ends of pipes are submerged in brake fluid.
 
3. Fill reservoir with new High Performance DOT-3 Motor Vehicle Brake Fluid C6AZ-19542-AB or equivalent meeting Ford specification ESA-M6C25-A, DOT-3.
 
4. Cover reservoir with clean shop towel.
 
5. CAUTION: Brake fluid is harmful to painted and plastic surfaces. If brake fluid is spilled onto a painted or plastic surface, immediately wash it with water. Pump brakes until clear, bubble-free fluid comes out of both brake tubes.
 
6. Remove short brake tubes and reinstall brake tubes from vehicle.
 
7. Bleed each brake line at brake master cylinder using the following procedure:
 

a. Have assistant pump brake pedal 10 times and then hold firm pressure on the brake pedal.
 
b. Loosen front brake line fitting with tubing wrench until stream of brake fluid comes out. Have assistant maintain pressure on brake pedal until brake line fitting is tightened again.
 
c. Repeat this operation until clear, bubble-free fluid comes out from around tubing fitting.
 
d. Repeat this bleeding operation at rear brake line fitting.

a. Fill brake master cylinder reservoir with new High Performance DOT-3 Motor Vehicle Brake Fluid C6AZ-19542-AB or equivalent meeting Ford specification ESA-M6C25-A, DOT-3.

b. Loosen both rear caliper bleeder screws and leave them open until clear brake fluid flows out. Be sure to check reservoir fluid level often and not let it run dry.

c. Tighten bleeder screws.

d. One at a time, loosen front caliper bleeder screws. Leave bleeder screws open until clear fluid flows out. Be sure to check reservoir level often and not let it run dry.

e. Tighten bleeder screws to 7-9 N-m (62-79 lb-in).

Manual Bleeding

The primary and secondary (diagonal split) hydraulic brake systems are individual systems and are bled separately. Bleed longest line first on individual system being serviced. During complete bleeding operation, do not allow brake master cylinder reservoir to run dry. Keep master cylinder reservoir filled with High Performance DOT-3 Motor Vehicle Brake Fluid C6AZ-19542-AB or equivalent meeting Ford specification ESA-M6C25-A, DOT-3. Never reuse brake fluid that has been drained from hydraulic system or has been allowed to stand in open container for an extended period of time.

1. To bleed brake system, position suitable box wrench on bleeder fitting on brake wheel cylinder. Attach rubber drain tube to bleeder fitting. The end of tube should fit snugly around bleeder fitting.
 
2. Submerge free end of the tube in container partially filled with clean brake fluid and loosen bleeder fitting approximately three-quarters of a turn.
 
3. Have assistant push brake pedal down slowly through its full travel. Close bleeder fitting and return the brake pedal to full release position. Repeat this operation until air bubbles cease to appear at submerged end of bleeder tube.
 
4. When fluid is completely free of air bubbles, secure bleeder fitting and remove bleeder tube.
 
5. Repeat this procedure for the opposite diagonal system. Refill brake master cylinder reservoir after each system is bled and install master cylinder reservoir cap and gasket. Make sure diaphragm-type gasket is properly positioned in master cylinder reservoir cap. When bleeding operation is completed, fluid level should be at MAX line to 4.0 mm (0.16 inch) below.
 
6. After disc brake service, make sure disc brake pistons are returned to their normal positions and shoe and lining assemblies are properly seated. This is accomplished by applying brake pedal several times until normal pedal travel is established.
 
7. Check pedal feel. If brake pedal feels spongy repeat bleed procedure.

Pressure Bleeding

For pressure bleeding, use bladder-type bleeder tank only, such as Rotunda Brake Bleeder 104-00064 or equivalent.

WARNING:
NEVER EXCEED 344 KPA (50 PSI) PRESSURE IN THE BRAKE BLEEDER TO PREVENT INJURY.

Bleed longest lines first. The bleeder tank should contain enough new brake fluid to complete bleeding operation. Use High Performance DOT-3 Motor Vehicle Brake Fluid C6AZ-19542-AB or equivalent fluid meeting Ford specification ESA-M6C25-A, DOT-3. Never reuse brake fluid that has been drained from hydraulic system. The tank should be charged with approximately 69-206 kPa (10-30 psi) of air pressure.

1. Clean all dirt from master cylinder reservoir cap.
 
2. Remove brake master cylinder filler cap (2162). Fill the brake master cylinder reservoir with specified brake fluid. Install pressure bleeder adapter tool to brake master cylinder and attach bleeder tank hose to fitting on adapter. Master cylinder pressure bleeder adapter tools can be obtained from various manufacturers. Follow instructions of the manufacturer to install adapter.
 
3. If the rear disc brake calipers are to be bled, use a suitable box wrench on bleeder fitting at the RH rear disc brake caliper. Attach bleeder tube snugly around bleeder fitting.
 
4. Open valve on bleeder tank to admit pressurized brake fluid into brake master cylinder reservoir.
 
5. Submerge free end of tube in container partially filled with clean brake fluid and loosen bleeder fitting.
 
6. When air bubbles cease to appear in fluid at submerged end of bleeder tube, close bleeder fitting. Remove tube. Replace rubber dust cap on bleeder screw.
 
7. Attach bleeder tube and repeat Steps 4, 5 and 6 at LH rear disc brake caliper.
 
8. On front brakes, repeat Steps 4, 5 and 6 starting at RH rear disc brake caliper and ending at LH disc brake caliper.
 
9. When bleeding operation is completed, close bleeder tank valve and remove tank hose from adapter fitting.
 
10. After disc brake service, make sure disc brake pistons are returned to their normal positions and shoe and lining assemblies are properly seated. This is accomplished by applying brake pedal several times until normal pedal travel is established.
 
11. Remove pressure bleeder adapter tool from brake master cylinder. Fill the brake master cylinder reservoir to the MAX line to 4 mm (0.16 inch) below. Install brake master cylinder filler cap.

Anti-Lock Brake System Bleeding

The service ABS hydraulic control unit is supplied filled with brake fluid. Therefore, a conventional bleed procedure should be adequate to remove all air from the brake system. However, if a spongy pedal is present and air in hydraulic control unit is suspected, use the following procedure.

Using Rotunda New Generation Star (NGS) Tester 007-00500 or equivalent:

1. Bleed entire system conventionally using a manual or pressure bleed procedure as described.
 
2. Attach pressure bleeder as described. Connect Rotunda New Generation Star (NGS) Tester 007-00500 or equivalent to serial data link connector (DLC) below instrument panel as though retrieving codes.
 
3. Make sure ignition switch is in RUN position.
 
4. Follow instructions on NGS screen. Choose correct vehicle and model year, go to Diagnostic Data Link menu item, choose ABS Module, choose Function Tests and choose Service Bleed.
 
5. RF Caliper Bleed

a. Open RF caliper bleed screw.
b. Start bleed program on NGS tester.
c. Bleed at RF caliper for at least 2 minutes.
d. Close RF bleed screw and press the red trigger button on the NGS tester.

a. Open LF caliper bleed screw.
b. Start bleed program on NGS tester.
c. Bleed at LF caliper for at least 2 minutes.
d. Close LF bleed screw and press the red Trigger button on the NGS tester.

a. Open LR caliper bleed screw.
b. Start bleed program on NGS tester.
c. Bleed at LR caliper for at least 2 minutes.
d. Close LR bleed screw and press the red Trigger button on the NGS tester.

a. Open RR caliper bleed screw.
b. Start bleed program on NGS tester.
c. Bleed at RR caliper for at least 2 minutes.
d. Close RR bleed screw and press the red Trigger button on the NGS tester.

 I am almost ashamed to have to ask this, but here it goes. I just  completed changing out rear brake calipers, rotors, and pads on my  96. I also replaced the front pads because they were about 40% and  I just decided to go ahead and do it anyways.   Here is the question. I have replaced all parts mentioned above,  and took my time to make sure that all went together correct.  Before I did this task, I had a dragging rear caliper and a nice  rock hard/firm pedal. Now that all is done, I have what I call a  soft almost fading brake pedal. I have bled and re-bled, and  gravity bled, and re-bled the system. Only to have flushed my  brake fluid system and still have a soft pedal. What am I missing.  Do I need to replace the rear lines too? Car has 125k and lines  appear to be factory equipment. I need to resolve this.   Mike Yeager

Here's the answer you need.

Our cars have a dual crossed hydraulic system. This means that the master cylinder has two pistons and two separate fluid circuits. The primary circuit feeds brake fluid to the Left Front and the Right Rear simultaneously. The secondary piston circuit feeds the Let Front and the Right Rear simultaneously. Both pistons move together and the primary piston uses fluid to move the secondary piston. When you let the master cylinder run dry, you lost this hydro-mechanical separation.

When bleeding the brakes, you get all 4 corners solid and free of air, then you must "Center the Pistons" in the master cylinder bore. You do this by bleeding the rears on the same pump of the pedal.

Have your pumping partner ready and pump the system up (4 to 5 pumps of the pedal) and hold. Start with the RR caliper and open the bleeder. The pedal will fall about half way and stop. Then without moving their foot on the brake pedal, go to the other side and open the bleeder. The pedal will then fall to the carpet. Repeat this a couple of times and reverse the procedure (start with the LR and on the same pump, bleed the RR). This purges both circuits of the master cylinder and allows the pistons to be positioned in the right place and supply normal braking pressure to all 4 wheels evenly.

Hope this helps.

Doug Lewis
Ford Performance Specialists Inc.
Atlanta Georgia
(770) 949-7191