Brake Drum: Service and Repair
REMOVAL1. Hoist vehicle and remove wheel.
2. Remove brake drum screws (2 pcs).
3. Release parking brake lever.
4. Remove parking brake lever cover screws and loosen parking brake cable locking nut.
5. Remove back plate plug attached to the back side of brake back plate so as to increase clearance between brake shoe and brake drum.
Insert a screwdriver into plug hole till its tip contacts shoe hold down spring and push screwdriver in the arrow direction.
With this push, hold down spring is pushed up and releases parking shoe lever from hold down spring, resulting in larger clearance.
6. Remove brake drum by using 8 mm bolts (2 pcs).
INSPECTION
Brake Drum
Inspect drum for cleanliness. Check wear of its braking surface by measuring its inside diameter.
Inside diameter "a"
Standard: 200 mm (7.87 inch)
Service Limit: 202 mm (7.95 inch)
Whenever brake drums are removed, they should be thoroughly cleaned and inspected for cracks, scores, deep grooves.
Cracked, Scored, or Grooved Drum
A cracked, drum is unsafe for further service and must be replaced. Do not attempt to weld a cracked drum. Smooth up any slight scores. Heavy or extensive scoring will cause excessive brake lining wear and it will probably be necessary to resurface drum braking surface. If brake linings are slightly worn and drum is grooved, drum should be polished with fine emery cloth but should no be turned.
NOTE: When drum is removed, visually inspect wheel cylinder for brake fluid leakage. Correct leaky point, if any.
Brake shoe
Where lining is worn out beyond service limit, replace shoe.
Thickness "a"
Standard: 6.1 mm (0.24 inch)
Service limit: 2.8 mm (0.11 inch)
If one of brake linings is to service limit, all linings must be replaced at the same time.
CAUTION: Never polish lining with sandpaper. If lining is polished with sandpaper, hard particles of sandpaper will be deposited in lining and may damage drum. When it is required to correct lining, replace it with a new one.
INSTALLATION
NOTE:
^ All brake fasteners are important attaching parts in that they could affect the performance of vital parts and systems, and/or could result in major repair expense. They must be replaced with one of same part number or with an equivalent part if replacement becomes necessary. Do not use a replacement part of lesser quality or substitute design. Torque values must be used as specified during reassembly to assure proper retention of all parts. There is to be no welding as it may result in extensive damage and weakening of the metal.
1. Before installing brake drum, to maximize brake shoe-to-drum clearance, put screwdriver between rod and ratchet and push down ratchet as shown in figure.
NOTE: Left figure shows ratchet position where brake shoe-to-drum clearance is maximum.
2. Put brake shoe hold down spring back to its original position as shown. (Put shoe hold down spring in place by moving shoe [ever so that shoe lever comes to the side of shoe hold down spring.)
3. Install brake drum after making sure that inside of brake drum and brake shoes are free from dirt and oil.
4. Upon completion of all jobs, depress brake pedal with about 30 kg (66 lbs.) load three to ten times so as to obtain proper drum-to-shoe clearance.
Adjust parking brake cable.
5. Install parking brake lever cover.
6. Install wheel and tighten wheel nuts to specified torque.
Tightening Torque (a): 85 Nm (8.5 kg.m, 61.5 ft. lbs.)
7. Check to ensure that brake drum is free from dragging and proper braking is obtained. Then remove vehicle from hoist and perform brake test (foot brake and parking brake).