.

INDEX

Brake Drum Removal
Brake Shoe Removal
Brake Drum Installation
Brake Shoe Installation
Cleaning and Inspection
Drum Refacing Recommendations
General Information
Installing Brake Supports
Removing Brake Supports
Special Procedures

GENERAL INFORMATION  (back to CONTENTS)

All drum brake applications are two shoe, internal expanding brakes with application adjusters. The lower ends of the brake shoes are connected by a tubular star wheel adjusting screw (Figs. 1 and 2).

CAUTION: When servicing brake assemblies or components, do not create dust by sanding, grinding or by cleaning brake parts with a dry brush or with compressed air. A water dampened cloth should be used. Many brake components contain asbestos fibers which can become airborne if dust is created during service operations. Breathing dust which contains asbestos fibers can cause serious bodily harm.

SERVICE PROCEDURES  (back to CONTENTS)

BRAKE DRUM REMOVAL  (back to CONTENTS)

(1) Remove rear plug from brake adjusting access hole.
(2) Insert a thin screwdriver into brake adjusting hole and hold adjusting lever away from notches of adjusting screw.
(3) Insert Tool C-3784 into brake adjusting hole and engage notches of brake adjusting screw. Release brake by prying down with adjusting tool.
(4) Remove rear wheel and clips from wheel studs that holds drum on axle. Discard clips. Remove drums.
(5) Inspect brake lining for wear, shoe alignment, or contamination from grease or brake fluid.

BRAKE SHOE REMOVAL  (back to CONTENTS)

(1) Remove rear wheel, and drum retaining clips. Remove drum.
(2) Using Tool C-3785, remove brake shoe return springs (Fig. 3). Note how secondary shoe return spring overlaps primary shoe return spring (Figs 1 or 2).
(3) Slide eye of automatic adjuster cable off anchor and then unhook from adjusting lever. Remove cable, overload spring, cable guide and anchor plate.
(4) Disengage adjusting lever from spring by sliding forward to clear pivot, then working out from under spring. Remove spring from pivot. Remove shoe to shoe spring from secondary shoe web and disengage from primary shoe web. Remove spring.
(5) Disengage primary and secondary shoes and remove adjusting star wheel assembly from shoes.
(6) Remove brake shoe retainers, springs and
nails using Tool C-4070, (Fig. 4), and remove from support.
(7) Remove parking brake lever from secondary shoes. Remove shoes.
(8) Disengage parking brake lever from parking brake cable.

CLEANING AND INSPECTION  (back to CONTENTS)

Wipe with a water dampened cloth the metal portions of the brake shoes. Examine the lining contact pattern to determine if the shoes are bent. The lining should show contact across the entire width, extending from heel to toe. Shoes showing contact only on one side should be replaced. Shoes having sufficient lining but lack of contact at toe and heel may be improperly ground.

Clean the support, using a suitable solvent, then inspect for rough or rusted shoe contact areas. Clean and inspect the adjusting screws for damaged threads, then apply a thin film of lubricant to the threads, socket and washer (Fig. 9). Replace adjuster screw assembly if corrosion of any part inhibits very free operation.

Install new brake shoe return springs and hold down springs where the old springs have been subjected to overheating or if their strength is questionable. Spring paint discoloration or distorted end coils indicate a spring that had been overheated.

DRUM REFACING RECOMMENDATIONS  (back to CONTENTS)

Drum Refacing
Measure the drum runout and diameter with an accurate gauge. There should be no variation in the drum diameter greater than .002 inch. Drum runout should not exceed .006 inch out of round. If the drum runout or diameter variation exceed these values the drum should be refaced. For best results in eliminating the irregularities that cause brake roughness and surge, the amount of material removed during a single cut should be limited to .005 inch. When the entire braking surface has been cleaned a final cut of .001 inch will assure a good drum surface providing the equipment used is capable of giving the precision required for resurfacing brake drums. Deeper cuts are permissible for the sole purpose of removing deep score marks. Do not reface more than .060 inch over the standard drum diameter.

All drums will show markings of maximum allowable diameter (Fig. 5). For example, a ten inch drum will have a marking of MAX. DIA. 10.090 inch. This marking includes .030 inch for allowable drum wear beyond the recommended .060 inch of drum refacing.

BRAKE SHOE INSTALLATION  (back to CONTENTS)

Lubricate the six shoe tab contact pads on support plate with a thin film of MOPAR MultiPurpose Lubricant, Part number 4318063 or equivalent (Fig. 6).
(1) Engage parking brake lever with cable. Install parking brake lever into rectangular hole of secondary brake shoe.
(2) Slide secondary shoe against support plate, at the same time engage shoe web with push rod and against anchor.
(3) Slid parking brake strut behind axle flange and into slot in parking brake lever. Slide antirattle spring over free end of strut (Fig. 7).
(4) Slide primary shoe into position and engage with push rod (if so equipped) and free end of strut. Install anchor plate over anchor, then install eye of adjuster cable over anchor (Fig. 8).
(5) Engage primary shoe return spring in web of shoe and install free end over anchor, using Tool C-3785.
(6) Insert protruding hole rim of cable guide into hole in secondary shoe web. Holding guide in position, engage secondary shoe return spring through both, hole in guide, and hole in web. Using Tool C-3785, install spring over anchor. (Be sure cable guide remains flat against shoe web and that secondary spring overlaps primary) (Fig. 1). Using pliers, squeeze ends of spring loops (around anchor) until parallel.
(7) Install adjusting star wheel assembly between primary and secondary shoes, with star wheel next to secondary shoe (Fig. 1). The left star wheel adjusting stud end is stamped “L” (indicating its position on the vehicle) and the star wheel is cadmium plated (Fig. 9). The right star wheel is black and the adjusting stud end is stamped “R”. Install shoe to shoe spring between shoes (Figs. 1 and 2). (Engage primary shoe first). (Eleven inch brakes, install shoe to shoe spring with coil forward, opposite adjuster lever, Fig. 2).
(8) Install adjusting lever spring over pivot pin on shoe web. Install adjusting lever under spring and over pivot pin. Slide lever slightly rearward to lock in position.
(9) Using Tool C-4070, install shoe retaining nails, retainers and springs (Fig. 4).
(10) Thread adjuster cable over guide and hook end of overload spring in lever (Fig. 1). (Be sure eye of cable is pulled tight against anchor and in a straight line with guide).

BRAKE DRUM INSTALLATION

(1) Install brake drum. Reinstallation of retaining clips is not necessary. Install wheel and tire assembly as described under “Wheel Stud Nut Tightening.”
(2) Adjust brakes as described under “Service Adjustments” at front of this Group.
(3) Reinstall plugs in adjusting access holes.

REMOVING BRAKE SUPPORT

(1) With wheel and brake drum removed, remove brake shoe assemblies and disconnect brake cable.
(2) Using a suitable tool such as an aircraft type hose clamp compress the flared legs of cable retainer and pull brake cable out of support plate (Fig. 10).
(3) Disconnect hydraulic brake tube from wheel cylinder.
(4) Remove wheel cylinder attaching bolts and pull wheel cylinder out of support.
(5) Remove rear axle shaft and retainer. Refer to “Rear Axle,” Group 3.
(6) Remove brake support from rear axle housing.

INSTALLING BRAKE SUPPORT

(1) Install support plate onto rear axle housing.
(2) Insert rear axle shaft and retainer into housing and install axle retainer nuts and washers. Refer to “Rear Axle,” Group 3.
(3) Install wheel cylinder and attach hydraulic brake tube.
(4) Insert parking brake cable into support plate and attach cable to parking brake lever.
(5) Install brake shoes on support plate.
(6) Install brake drum and wheel. Adjust and bleed brakes..