Drum Brake System: Service and Repair

REAR DRUM BRAKE






Removal

WARNING: Clean brake lining with a vacuum dust collector to minimize the hazard of airborne asbestos or other materials.

CAUTION: Make sure parking brake lever is released completely.

1. Release parking brake lever fully, then remove drum. If drum is hard to remove, the following procedures should be carried out.





a. Remove plug. Then shorten adjuster to make clearance between brake shoe and drum as shown.





b. Tighten the two bolts gradually.





2. After removing shoe hold pin by rotating push retainer, remove leading shoe then remove trailing shoe. Remove spring by rotating shoes in direction arrow. Be careful not to damage wheel cylinder piston boots.
3. Remove adjuster.





4. Disconnect parking brake cable from toggle lever. Be careful not to damage parking brake cable when separating it.





5. Remove retainer ring with a suitable tool. Then separate toggle lever and brake shoe.

Inspection
WHEEL CYLINDER





^ Check wheel cylinder for leakage.
^ Check for wear, damage and loose conditions. Replace if any such condition exists.

Wheel Cylinder Overhaul





^ Check all internal parts for wear, rust and damage. Replace if necessary.
^ Pay attention so as not to scratch cylinder when installing pistons.

Inspection
DRUM





Maximum inner diameter: 296.5 mm (11.67 inch)
Out-of-roundness: 0.03 mm (0.0012 inch) or less
^ Contact surface should be fine finished with No. 120 to 150 emery paper.
^ Using a drum lathe, lathe brake drum if it shows scoring, partial wear or stepped wear.
^ After brake drum has been completely reconditioned or replaced, check drum and shoes for proper contact pattern.

LINING





Check lining thickness.
Standard lining thickness: 6.1 mm (0.240 inch)
Lining wear limit (A): 1.5 mm (0.059 inch)

Installation
Always perform shoe clearance adjustment.





1. Fit toggle lever to brake shoe (trailing side) with retainer ring.





2. Apply brake grease to the contact areas (indicated by arrows and hatching) shown.
3. Shorten adjuster by rotating it.











^ Pay attention to direction of adjuster.
4. Connect parking brake cable to toggle lever.
5. Install all parts. Be careful not to damage wheel cylinder piston boots.
6. Check all parts are installed properly. Pay attention to direction of adjuster assembly.
7. Install brake drum.
8. When installing new wheel cylinder or overhauling wheel cylinder, bleed air.
9. Adjust parking brake.