Drum Brake Adjustment (4 2 Model); Servicing The Brake Drum - Isuzu 1999 RODEO Workshop Manual

5C–56 POWER–ASSISTED BRAKE SYSTEM
10. Install lower return spring (5).
f Use brake spring tool.
11. Install auto adjuster lever (10).
12. Install upper (outer) return spring (6).
f Use brake spring tool.
13. Install brake drum (2).
f Adjust the brakes, refer to the "Drum Brake
Adjustment" in this section.
14. Install wheel and tire assembly (1).
f Refer to "Wheels and Tires " in wheel and Tire
System section.

Drum Brake Adjustment (4 2 Model)

NOTE: All brakes are self-adjusting. Brakes are adjusted
by repeated stepping on the brake pedal. (After stepping
on the pedal and releasing it, the rear auto adjuster, in the
rear brake, produces a clicking sound.
The same operation should be repeated until the sound
disappears.)
Take the following steps after overhauling the rear brake
assembly.
1. Move the parking brake handle to its fully released
position.
2. Parking cable must be loosened sufficiently. (Loosen
the adjust nut and the lock nut.)
3. Repeat stepping on the brake pedal firmly, and
releasing it until the clicking sound can no longer be
heard.
If the difference between the brake drum inside
diameter and diameter of the brake shoes is adjusted
to be 0,5 mm, the number of times for depressing the
brake pedal can be reduced.
4. Remove the drum. Measure the brake drum inside
diameter and diameter of the brake shoes.
Shoe clearance: 0.25-0.4 mm (0.0098-0.0157 in)
If incorrect, check the brake auto-adjusting system.
5. Rotate the adjust nut until all slack disappears from
the cable. Set the adjust nut.
6. Applying about 30 kg (66 lb) of force, pull the parking
brake handle to its fully set position three or four
times.
7. If the parking brake is properly adjusted, the travel
between the fully disengaged position and the fully
engaged position will be between 9 and 11 notches.
If the traveling range is not within these limits, again
repeat steps 1 through 5.
After adjusting has been done, check to see if the rear
wheel rotates smoothly without drag when turned by
hand.

Servicing The Brake Drum

Whenever the brake drums are removed, they should be
thoroughly cleaned and inspected for cracks, scores,
deep grooves and out-of-round.
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 any slight scores. Heavy or extensive scoring will
cause excessive brake lining wear, and it will probably be
necessary to machine the drum braking surface.
If the brake linings are slightly worn and the drum is
grooved, the drum should be polished with fine emery
cloth but should not be machined.
eliminating all the grooves in the drum and smoothing the
ridges on the lining would require the removal of too much
metal and lining. If left alone, the grooves and ridges
match and satisfactory service can be obtained. If brake
linings are to be replaced, a grooved drum should be
machined. A grooved drum, if used with a new lining, will
not only wear the lining, but will make it difficult, it not
impossible, to obtain efficient brake performance.
Out-Of-Round Drum
An out-of-round drum makes accurate brake shoe
adjustment impossible and is likely to cause excessive
wear to other parts of the brake mechanism due to its
eccentric action. An out-of-round drum can also cause
severe and irregular tire tread wear as well as a pulsing
brake pedal. When the braking surface of a brake drum
exceeds the specification limit of 0.15 mm (0.006 in) in
out-of-round, the drum should be machined to true up the
braking surface. Out-of-round can be accurately
measured with an inside micrometer fitted with proper
extension rods. When measuring a drum for out-of-round
and wear, take measurements at the open and closed
edges of machines surfaces and at right angles to each
other.
Maximum out-of-round: 0.15 mm (0.006 in)
At this stage,
420RS034