Continental 2000-2002

Power Brake Booster

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Adjustments



With ABS

The booster pushrod (output rod) is not adjustable. The pushrod length is set during assembly. A properly set pushrod that remains within the assembled booster after it was assembled in production, should never require service.

A booster that is suspected of having an improper set pushrod length will indicate either of the following:



A pushrod that is too long will prevent the master cylinder piston from completely releasing hydraulic pressure and causing the brakes to drag.
 
A pushrod that is too short will increase brake pedal travel and cause a clunk or groaning noise to come from the booster.
 

If necessary, booster pushrod length can be verified with a depth micrometer using the following procedure:

  1. With the engine OFF, depress the brake pedal several times to deplete the vacuum in the brake booster.
  2.  
  3. Without disconnecting the brake lines, disconnect the master cylinder and position it away from the booster. The master cylinder must be supported to prevent damaging the brake lines.
  4.  
  5. Measure the pushrod length while a force of approximately 5 lbs. is applied to the pushrod end. The correct pushrod dimension is 1.11 in. plus or minus 0.01 in. (28.3mm plus or minus 0.3mm) as measured from the master cylinder mounting surface.
  6.  
  7. If the pushrod dimension is correct, install the master cylinder on the booster and alternately tighten the attaching nuts to 21 ft. lbs. (29 Nm).
  8.  
  9. If the pushrod dimension is incorrect, the booster must be replaced.
  10.  

Without ABS

The power brake booster has an adjustable pushrod (output rod) that is used to compensate for dimensional variations in an assembled booster. The pushrod length is adjusted after each booster power unit has been assembled in production. A properly adjusted pushrod that remains assembled to the booster with which it was matched in production should never require adjustment.

A booster that is suspected of having an improper pushrod length will indicate either of the following:



A pushrod that is too long will prevent the master cylinder piston from completely releasing hydraulic pressure, eventually causing the brakes to drag.
 
A pushrod that is too short will increase brake pedal travel and cause a groaning noise to come from the booster.
 

If necessary, booster pushrod length can be verified using the following procedure. It will be necessary to fabricate a gauge of the dimensions shown in Figs. 8 or 9.

  1. Without disconnecting the brake lines, disconnect the master cylinder and position it away from the booster. The master cylinder must be supported to prevent damaging the brake lines.
  2.  
  3. With the engine running, gauge and adjust the pushrod length from the knurled area. A force of approximately 5 lbs. applied to the pushrod with the gauge will ensure that the pushrod is seated within the power unit.
  4.  
  5. Install the master cylinder on the booster. Gradually alternate tightening the attaching nuts to 21 ft. lbs. (29 Nm).
  6.  


NOTE
Do not adjust the pushrod too long or brake drag could result.



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Fig. Dimensions for booster pushrod length gauge-1989 vehicles



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Fig. Dimensions for booster pushrod length gauge-1990-93 vehicles



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Fig. Power brake booster pushrod length adjustment

Removal & Installation



With ABS
  1. Disconnect the negative battery cable.
  2.  
  3. Pump the brake pedal until all vacuum is removed from the booster. This will prevent the O-ring from being sucked into the booster during disassembly.
  4.  
  5. Remove the electrical connector bracket retaining nut from the master cylinder stud and disconnect the connector.
  6.  
  7. Working in the engine compartment, remove the cruise control actuator cable and cruise control servo; refer to Section 6.
  8.  
  9. Disconnect the manifold vacuum hose from the booster check valve.
  10.  
  11. Disconnect the fluid level indicator electrical connector from the master cylinder reservoir cap.
  12.  
  13. Disconnect the brake lines from the master cylinder outlet ports and remove the Hydraulic Control Unit (HCU) supply hose. Plug the ports and reservoir feed to prevent brake fluid from leaking onto paint and wiring.
  14.  
  15. Working inside the passenger compartment, disconnect the brake light switch electrical connector from the switch. Disengage the pedal position switch from the stud.
  16.  
  17. Remove the hairpin retainer and outer nylon washer from the pedal pin. Slide the brake light switch off the pedal just far enough for the arm to clear the pin. Remove the switch, being careful not to damage it during removal.
  18.  
  19. Remove the booster-to-dash panel attaching nuts. Slide the bushing and booster pushrod off the brake pedal pin.
  20.  
  21. From inside the engine compartment, move the booster forward until the booster studs clear the dash panel. Remove the booster/master cylinder assembly and place it on a clean bench.
  22.  
  23. Remove the master cylinder-to-booster nuts and slide the master cylinder away from the booster.
  24.  

To install:

  1. Make sure the O-ring is in place in the groove on the master cylinder, then slide the master cylinder onto the booster studs. Install the nuts and tighten to 21 ft. lbs. (29 Nm).
  2.  
  3. Position the booster/master cylinder assembly on the dash.
  4.  
  5. Working inside the passenger compartment, install the booster pushrod and bushing on the brake pedal pin. Install the booster-to-dash panel nuts and tighten to 21 ft. lbs. (29 Nm).
  6.  
  7. Position the brake light switch so it straddles the booster pushrod with the switch slot toward the pedal blade and the hole just clearing the pin. Slide the switch completely onto the pin. Be careful not to bend or deform the switch.
  8.  
  9. Install the nylon washer on the pin, and secure all parts to the pin with the hairpin retainer. Make sure the retainer is fully installed and locked over the pedal pin. Connect the brake light switch electrical connector.
  10.  
  11. Install and adjust the pedal travel switch as explained in this Section.
  12.  
  13. Install the cruise control servo and cruise control actuator cable; refer to Section 6.
  14.  
  15. Connect the brake lines to the master cylinder and attach the low pressure hose to the reservoir.
  16.  
  17. Connect the manifold vacuum hose to the booster check valve and the electrical connector to the master cylinder reservoir cap.
  18.  
  19. Connect the electrical connector and install the retaining bracket and nut.
  20.  
  21. Connect the negative battery cable. Bleed the brake system.
  22.  



Click image to see an enlarged view

Fig. Power brake booster-with ABS

Without ABS
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the master cylinder from the booster and move it aside without disconnecting the brake lines. Be careful not to kink the brake lines.
  4.  
  5. Disconnect the manifold vacuum hose from the booster check valve.
  6.  
  7. Working inside the vehicle below the instrument panel, remove the brake light switch connector. Remove the switch-retaining pin and slide the switch off the brake pedal pin just far enough for the outer arm to clear the pin, then remove the switch. Be careful not to damage the switch.
  8.  
  9. Remove the booster-to-dash panel attaching nuts.
  10.  
  11. Slide the booster pushrod, nylon washers, if equipped, and bushing off the brake pedal pin. Slide the pushrod out from the engine side of the dash panel and remove the booster.
  12.  

To install:

  1. Place the booster in position on the dash panel.
  2.  
  3. Working inside the vehicle, Install the inner nylon washer, if equipped, booster pushrod and bushing on the brake pedal pin. Install the booster-to-dash panel attaching nuts and tighten to 21 ft. lbs. (29 Nm).
  4.  
  5. Position the brake light switch so it straddles the booster pushrod with the switch slot toward the pedal blade and the hole just clearing the pin. Be careful not to bend or deform the switch.
  6.  
  7. Install the nylon washer on the pin, and secure all parts to the pin with the hairpin retainer. Make sure the retainer is fully installed and locked over the pedal pin. Connect the brake light switch electrical connector.
  8.  
  9. Connect the manifold vacuum hose to the booster check valve using a hose clamp.
  10.  
  11. Install the master cylinder and tighten the nuts to 21 ft. lbs. (29 Nm).
  12.  
  13. Connect the negative battery cable. Start the engine and check power brake operation.
  14.  



Click image to see an enlarged view

Fig. Power brake booster-without ABS

Testing



System Operation
  1. With the engine OFF , pump the brake pedal until the supply vacuum is entirely gone.
  2.  
  3. Put light, steady pressure on the brake pedal.
  4.  
  5. Start the engine and let it idle. If the system is operating correctly, the brake pedal should fall toward the floor if the constant pressure is maintained.
  6.  

Power brake systems may be tested for hydraulic leaks just as ordinary systems are tested.


WARNING
Clean, high quality brake fluid is essential to the safe and proper operation of the brake system. You should always buy the highest quality brake fluid that is available. If the brake fluid becomes contaminated, drain and flush the system, then refill the master cylinder with new fluid. Never reuse any brake fluid. Any brake fluid that is removed from the system should be discarded.



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Fig.



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Fig.



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Fig.

Vacuum Leak Test
  1. Operate the engine at idle without touching the brake pedal for at least one minute.
  2.  
  3. Turn off the engine and wait one minute.
  4.  
  5. Test for the presence of assist vacuum by depressing the brake pedal and releasing it several times. If vacuum is present in the system, light application will produce less and less pedal travel. If there is no vacuum, air is leaking into the system.
  6.  

 
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