Hino 600, Workshop Manual, Page: 246 / 451

SERVICE BRAKE (HYDRAULIC BRAKE) BR02–2
HYDRAULIC BRAKE
INSPECTION AND ADJUSTMENT
EN1680102H600001
1. REMAINING THICKNESS OF PAD
Inspect the pad thickness. If the pad thickness is less than the
service limit or if it is foreseen that it may be worn to the service
limit before the next inspection, replace it with a new one.
Four piston type
Assembly Standard: 18.5 mm {0.728 in.}
Service Limit: 3.2 mm {0.125 in.}
! WARNING
If a pad which has become thinner than the limit is left unreplaced, the
rotor may be damaged by the pad back-plate and the braking force will
be badly degraded. Be sure to check carefully the worn state of the
brake pad of all wheels.
2. BRAKE FLUID LEAK AND POWER STEERING FLUID LEAK
(1) Check for fluid leaks.
a.
Fluid leaks from lines.
With the brake pedal depressed, visually check for leaks of brake
fluid from the brake hydraulic line including the pipes, connection,
hoses, etc. If any leak is found, repair or replace with the corre-
sponding parts.
b. When checking for leaks, check also the following items and
repair or replace with the corresponding parts as required.
a) Check that the pipes and hoses are not hitting or rubbing other
parts. Check that the pipe clips are not loose.
b) Check that the pipes have no cracks and that they have not
become rusty.
c) Check that the hoses are not deteriorated, deformed, or swol-
len.
NOTICE
As a general rule, the brake hoses should be replaced with new ones
every 36,000 miles (60,000 km) or 12 months. When any defects as
above have been found, replace immediately with new ones.
c. Fluid leaks from components other than lines.
If the pedal stroke gradually increases as the brake pedal is kept
pressed (in the worst case the brake pedal reaches the cab floor),
a probable cause is that there is an internal leak in any one of the
following components;
•
Master cylinder
• Hydraulic booster
•
Caliper piston in wheel brake