Hino 600, Workshop Manual, Page: 304 / 451

SERVICE BRAKE (FULL AIR BRAKE) BR02–26
3. REMOVAL
(1) Chock the vehicle wheels or park the vehicle by mechanical means.
(Block and hold vehicle by means other than air brakes.) Drain all air
system reservoirs.
(2) Identify and disconnect all supply and delivery lines at the brake valve.
(3) Remove the brake valve and treadle assembly from the vehicle by
removing the three cap screws on the outer bolt circle of the mounting
plate. The basic brake valve alone can be removed by removing the
three cap screws on the inner bolt circle.
4. DISASSEMBLY
(1) If the entire brake valve and treadle assembly was removed from the
vehicle, remove the three cap screws securing the treadle assembly
to the basic brake valve.
(2) Remove the screw (9) securing the exhaust diaphragm (10) and
washer (11) to the exhaust cover (12).
(3) Remove the four screws that secure the exhaust cover (12) to the
lower body.
(4) Remove the secondary inlet and exhaust valve assembly (13) from
the lower body.
(5) Remove the four hex head cap screws securing the lower body to the
upper body and separate the body halves.
(6) Remove the rubber seal ring (14) from the lower body.
(7) For E-8P: While applying thumb pressure to the primary piston (22),
lift out and up on the three lock tabs of the primary piston retainer
(15).
! CAUTION
Before proceeding with the disassembly, refer to figures on pages
BR02-23 and 24, and note that the lock nut (16) and stem (17) are used
to contain the primary piston return spring (for E-8P: 23), stem spring
(19), and the relay piston spring (21). The combined force of these
springs is approximately 50 pounds and care must be taken when
removing the lock nut as the spring forces will be released. It is rec-
ommended that the primary piston and relay piston be manually or
mechanically contained while the nut and stem are being removed.
(8) Using a 3/8" wrench, hold the lock nut (16) on the threaded end of the
stem (17). Insert a screwdriver to restrain the stem, remove the lock
nut (16), spring seat, (18) and stem spring (19).
(9) Remove the relay piston (20), relay piston spring (21), primary piston
(
E-8P: 22) and primary piston return spring ( E-8P: 23) from the upper
body. Use care so as not to nick seats.
(10) A small washer (24) will be found in the cavity of the lower side of the
primary piston ( for E-8P : 22).
(11) For E-8P: Disassemble the primary piston by rotating the spring seat
nut (25) counterclockwise. Separate the spring seat nut, spring seat
(26), and rubber spring (27) and remove the piston o-ring (28).
(12) Remove the large and small o-rings (30 & 31) from the relay piston
(20).
(13) Remove the retaining ring (32) securing the primary inlet and exhaust
valve assembly (33) in the upper body and remove the valve assem-
bly.
5. CLEANING AND INSPECTION
(1) Wash all metal parts in mineral spirits and dry.
(2) Inspect all parts for excessive wear or deterioration.
(3) Inspect the valve seats for nicks or burrs.
(4) Check the springs for cracks or corrosion.
(5) Replace all rubber parts and any part not found to be serviceable dur-
ing inspection, use only genuine Bendix replacement parts.