Attachment III - Technical Instructions
Installation Of A Parking Brake Lock-In WedgeAffected Vehicles:
Certain 1992-1994 Model Year Bronco, F-150-350 Series Trucks and certain 1993-1994 Model Year Explorer/Ranger Trucks equipped with manual transmissions.
Technical Instructions
NOTE:
It is imperative that you fully read the following procedures and complete all the steps in the procedure. This procedure includes some inspection and verification steps in addition to those included in prior TSB's on this subject.
Inspection
1. Park the vehicle in a flat area. Turn the ignition "OFF".
2. If the vehicle is a 1992 or 1993 F-Series or Bronco, inspect the release rod and spring for proper position.
The release rod must be fully inserted into the slot in the bracket and the spring must be located behind the slot in the bracket. Refer to Figure 1.
3. Inspect parking brake control assembly to determine what action is required.
a. If the parking brake control assembly is of the new cam-in post design. it does not require installation of the wedge. See Figure 2. DO NOT PROCEED. File form 1864 for inspection only and release the vehicle.
b. If the wedge has been previously installed as illustrated in Figure 3.
^ If wedge is properly installed, go to PARKING BRAKE FUNCTIONAL TEST.
^ If wedge is not installed as shown in figures, remove wedge as outlined in Steps 1 through 4 of PARKING BRAKE ADJUSTMENT PROCEDURE, then continue with WEDGE INSTALLATION.
c. If the wedge is not present or the vehicle is not equipped with the cam-in post design parking brake control assembly, proceed with WEDGE INSTALLATION.
NOTE:
Previously installed wedges may be translucent rather than white (Bronco/F-Series) or Black (Ranger/Explorer).
Lock-In Wedge Installation
1. Apply and release parking brake at least six (6) times allowing pedal to return each item without any interference. This will "neutralize" the parking brake cable system and allow for proper evaluation of the system once the wedge is installed.
2. Apply foot pressure to the pedal so that the pedal rotates (about 2-1/2" to 3") from the "RELEASED" position. See Figure 4.
WARNING
BE CAREFUL NOT TO ACCIDENTALLY RELEASE THE PARKING BRAKE SPRING LOADED RELEASE ARM DURING THE INSTALLATION PROCEDURE BY PULLING ANYWHERE ON THIS RELEASE LEVER.
3. Check that the pawl is fully seated in the bottom of a ratchet tooth. See Figure 5. If not, re-cycle pedal as outlined in Step 2.
4. After full engagement of the pawl and ratchet is assured, apply foot pressure to the pedal to fully rotate the pedal to the full "APPLIED" position (this allows you more room to make installation easier). See Figure 6.
5. Grab the tab of the wedge (Figure 7) with needle nose pliers and position it so that the small teeth on the concave surface are pointing up.
NOTE:
The Explorer/Ranger and Bronco/F-Series wedges are not the same.
The wedge for the Explorer/Ranger is black, and the wedge for the Bronco/F-Series is white. See Figure 8 for identification of the wedges.
6. Using needle nose pliers, insert the wedge between the pawl and the ratchet with the flange of the wedge behind the pawl and ratchet. See Figure 9.
7. Check that the wedge is properly located between the pawl and the ratchet and that the flange is behind the pawl and ratchet.
8. Use a small hammer and punch to apply light force to the back end (or drive area) of the wedge. See Figure 10.
9. Use sufficient force to ensure adequate seating of the wedge into the ratchet teeth. On Explorer/Ranger models, more force may be required to completely seat wedge. Check the wedge for proper alignment with the pawl after seating. See Figure 11.
10. After the wedge is properly seated, cycle the lever mechanism "APPLIED" and "RELEASED" a minimum of six (6) times, leaving the pedal in the full "APPLIED" position after the last application.
11. Recheck the wedge to be sure it is fully engaged in its proper position.
NOTE:
The parking brake light should be off when the parking brake is released. If the light is on with the parking brake released, check the wedge installation (Step 9).
Parking Brake Functional Test
NOTE:
The installation of the lock-in wedge disables the self-adjusting feature of the parking brake control assembly. The following parking brake functional test must be performed to verify proper parking brake system adjustment.
1. Place vehicle on hoist with the transmission in neutral.
a. Verify the parking brake is fully released. Check for brake drag by turning the rear wheels by hand.
b. Check for a firm pedal feel while fully applying the parking brakes.
2. If vehicle experiences either brake drag or a "soft" pedal, go to PARKING BRAKE ADJUSTMENT PROCEDURE.
Parking Brake Adjustment Procedure
NOTE:
Perform the following adjustment procedure only if directed here from the Parking Brake Functional Test or only perform Steps 1 thru 4 if wedge removal is required.
To perform the parking brake adjustment procedure, the lock wedge must first be removed from the control assembly. Upon completion of the adjustment procedure, the wedge must be reinstalled.
1. To remove the wedge, apply pressure to the pedal until a full travel position is achieved. The pedal will be in a vertical position.
2. Use a pair of standard pliers or needle nose vice grips to grip the tab of the lock-in wedge.
WARNING
CARE MUST BE USED TO AVOID ACTIVATING THE RELEASE LEVER DURING WEDGE REMOVAL.
3. With a twisting motion, pull out the wedge.
4. Inspect the wedge for damage. If the tab is broken off, if it is missing teeth or if it is severely damaged in any other fashion, discard it. Obtain a new wedge for installation.
5. Release the parking brake.
6. With the vehicle still on a hoist, have an assistant rotate one rear wheel to check for drag while you pull on the appropriate cable until a slight drag is felt at the wheel.
a. F-Series/Bronco - pull forward on corresponding rear cable at equalizer.
b. Explorer/Ranger - pull forward on front cable.
7. At this point, push rearward on the cable a slight amount until the wheel spins freely.
8. Have the assistant rotate the opposite wheel and adjust the corresponding cable as outlined in steps 6 and 7.
9. Recheck the first wheel to verify correct parking brake adjustment.
10. Apply the parking brake and install wedge as outlined in steps 2-11 of LOCK-IN WEDGE INSTALLATION.
11. Perform PARKING BRAKE FUNCTIONAL TEST.