The rear brake drums must be removed in order for the shoes may be inspected and measured for remaining thickness. Use a cloth dampened with water to wipe down the components or use an aerosol brake cleaner. Do not use a dry brush or air to clean the shoes. Measure the friction material (not the backing plate) at the thinnest point. Refer to the Brake Specifications chart for minimum thicknesses.
It is a characteristic of brake shoes to show slightly uneven wear or for each shoe to wear differently. A shoe may have very different thicknesses at opposite ends; if the rest of the system is in good condition, this is not a sign of a problem.
REMOVAL & INSTALLATION 1979-86 Models
See Figures 1, 2, 3 and 4
- Raise and support the vehicle.
- Remove the rear wheel, drum retaining clips and the brake drum.
- Remove the brake shoe return springs, noting how the secondary spring overlaps the primary spring.
- Remove the brake shoe retainer, springs and pins.
- Disconnect and remove the automatic adjuster cable from the lever.
- Remove the spring and lever from the shoe web.
- Spread the anchor ends of the primary and secondary shoes and remove the parking brake spring and strut.
- Disconnect the parking brake cable.
- The primary and secondary brake shoes and the star adjuster can be removed as an assembly. If not remove them separately and arrange the components in an order for assembly.
- Apply a thin coat of lubricant to the support platforms.
- Attach the parking brake lever to the back side of the secondary shoe.
- Place the primary and secondary shoes in their relative positions on a workbench.
- Lubricate the adjuster screw threads. Install it between the primary and secondary shoes with the star wheel next to the secondary shoe.
- Overlap the ends of the primary and second brake shoes and install the adjusting spring and lever at the anchor end.
- Hold the shoes in position and install the parking brake cable into the lever.
- Install the parking brake strut and spring between the parking brake lever and primary shoe.
- Place the brake shoes on the support and install the retainer pins and springs.
The spring for the primary shoe is green and the secondary shoe is colored gray. Do not mix them up, as they are different lengths.
- Install the anchor pin plate.
- Install the eye of the adjusting cable over the anchor pin and install the return spring between the anchor pin and primary shoe.
- Install the cable guide in the secondary shoe and install the secondary return spring. Be sure that the primary spring overlaps the secondary spring.
- Position the adjusting cable in the groove of the cable guide and engage the hook of the cable in the adjusting lever.
To check the adjuster assembly operation, pull the adjuster cable toward you to see if the adjuster lever goes into mesh with the next tooth on the wheel. Make sure that when the cable is released, the adjuster lever returns to its original position after the adjuster wheel has moved a tooth ahead.
- Install the brake drum and retaining clips. Install the wheel and tire.
- Adjust the brakes and road test the truck.
1987-93 Models See Figures 5 through 24
Disassemble the brakes one wheel at a time. This will prevent parts confusion and also prevent the opposite wheel cylinder pistons from popping out during repair. While this work can be accomplished with common hand tools, there are several specialty brake tools available in automotive parts and retail stores which can make the job easier. The brake spring tool, in particular, is strongly recommended.
- Raise and safely support the vehicle on jackstands.
- Remove the rear brake drums as described above.
- Using brake spring pliers, disconnect the shoe retainer spring (the bottom spring connected to both brake shoes) and disconnect the shoe return spring (the spring which is wrapped around the adjuster) and brake shoe adjuster.
- Remove the shoe hold-down spring on either side by first depressing slightly and then twisting the retaining cap (there is a common brake tool that is designed to make this almost effortless). The pins can rotate in the backing plate, so reach around with one hand to keep the pin from spinning while twisting the retaining caps. The tangs on the retaining post must line up with the notches in the cap; release the cap in this way and then remove the cap, spring, and spring seat. Remove shoe retaining spring with the pliers.
- Remove the shoe, to which the parking brake cable is not attached.
- Remove the other shoe then disconnect the parking brake cable at the shoe. It's easier to disconnect the cable with the shoe removed from the backing plate, but can be done otherwise if you wish.
- If the parking brake cable is to be removed entirely, you can now remove the snapring at the backing plate and pull the end of the cable through.
- First grease the surfaces of the shoe that will contact the backing plate (this means the side edge of the shoe, NOT the friction surface), the backing plate contact points, and the working surfaces of the anchor plate and wheel cylinder pistons. Use a grease recommended for precisely this application SAE J310, NLGI No. 1); not all lubricants are appropriate.
- Assemble hold down pins and springs and install the parking brake cable to the shoe. Install the shoe and secure the spring pin with the push-and-twist motion. (This can become a three-handed job; an assistant may be required.).
- Install the other shoe and secure it.
Install the adjusting mechanism and springs, making sure the springs are in the correct position. It is quite possible to install the springs backwards; this will cause impaired function and noise. When installing the shoe retainer spring and the shoe return spring, screw the adjuster in to its narrowest setting. To correctly install the shoe return spring and adjuster, follow this procedure:
- Install the right-hand thread brake adjuster to the left-hand side brake, and the left-hand thread brake adjuster to the right-hand side brake.
- Install the brake shoe adjuster, so that the identification grooves face outward.
- Attach the longer end of the shoe return spring to the shoe and lever assembly.
- Turn the brake shoe adjuster to adjust the outside diameter of the brake shoe assembly.
The adjuster on these models has an identification groove on the non-forked end. This groove must face outward at installation.
- Double check the placement and installation of all components. Everything must be accurately placed and securely fastened.
Use the adjuster to set the brakes to the correct diameter. Use an accurate measuring device to measure the outer diameter of the brake shoes. This measurement must be set correctly; otherwise either the drum will not go over the shoes or the adjustment will be too loose. Correct measurements are:
Pick-up, 2WD 1983-86: 24.00-24.05cm
- Install the brake drum as described above.
- Install the wheels. Make sure you depress the brake pedal repeatedly to fully adjust the self-adjusters before operating the vehicle. Operate the vehicle at very low speed in both forward and reverse gears, pumping the brake pedal repeatedly. Bring the vehicle to a full stop and operate the parking brake several times. Pedal feel should be normal, but the vehicle should roll freely (with no drag) when the pedal is released. If any condition is abnormal, the brake adjustment and/or components must be investigated and corrected.