Drum Brake System: Service and Repair

REMOVAL

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

CAUTION: Make sure parking brake lever is completely released.

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.

Brake Drum Removal:

b. Install two bolts as shown. Tighten the two bolts gradually.

Rear Brake Parts Location:

2. After removing retainer, remove spring by rotating shoes.

CAUTION:
^ Be careful not to damage wheel cylinder piston boots.
^ Be careful not to damage parking brake cable when separating it.

3. Remove adjuster.
4. Disconnect parking brake cable from toggle lever.

Toggle Lever Pin Removal:

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.

Drum





- Maximum inner diameter: 181 mm (7.13 inch)
- Maximum out-of-round: 0.03 mm (0.0012 inch)
- Contact surface should be fine finished with No. 120 to 150 emery paper.
- Using a drum lathe, resurface 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: 4.0 mm (0.16 inch)
Lining wear limit: 1.5 mm (0.059 inch)

INSTALLATION
Always perform shoe clearance adjustment.
1. Fit toggle lever to brake shoe with retainer ring.





2. Apply brake grease to the contact areas shown.
3. Shorten adjuster by rotating it.

Brake Adjuster Installation:

NOTE:
Pay attention to direction of adjuster.
- Left wheel (lefthand thread): Depression
- Right wheel (righthand thread): No depression

4. Connect parking brake cable to toggle lever.
5. Install all parts.

NOTE: Be careful not to damage wheel cylinder piston boots.





6. Check all parts are installed properly.

NOTE: Pay attention to direction of adjuster assembly.

7. Install brake drum.
8. When installing new wheel cylinder or overhauling wheel cylinder, bleed air. Refer to Bleeding Procedure.
9. Adjust parking brake.