Bendix Commercial Vehicle Systems A2LS HYD DRUM BRAKES W/PARKING 2/08 - Manual (Page 7)

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4. Place the recessed end of a 3/8 inch (9,53 mm) square
drive socket extension over the end of the wheel cylinder
end shoe return spring, Figure 12. Tap the end of the
socket extension until the hook end of the spring passes
through the brake shoe web.
5. Shape a length of drill rob, or equivalent tool steel, into a
tool as shown in Figure 13.
6. Insert the end of the tool into the loop on the end of the
shoe return spring. Using the expander unit body as a
fulcrum, unhook the spring from the brake shoe web,
Figure 25. Be careful not to damage the rubber dust
boot. Note: The brake shoe return spring is hooked into
the back side of the shoe web.
7. Ease the shoes from under the shoe hold down clips
(where fitted) and remove the back shoes.
8. Remove the tappet head and manual override assemblies
from the wheel cylinder units.
9. To rapidly un-adjust the adjusters, fit a piece of 3/4 inch
(19,05 mm) heater hose inside a suitable 12 point socket,
Figure 14, on either a speedbrace or ratchet drive. Place
the heater hose over the piston neck and fully wind back
the adjusters as shown in Figure 14. A load must be
applied to the wheel cylinder piston while winding back
the adjusters.
Note: To avoid locking the auto-adjuster mechanism in the
fully un-adjusted position, wind out each wheel cylinder
piston one complete turn after fully un-adjusting the
pistons.
10. Inspect the wheel cylinder unit and expander unit for
leaks. Lift the dust boots at their inner diameters from
the tappets and pistons. If fluid escapes when the dust
boots are lifted, the wheel cylinder or expander must be
removed for service. Follow the instructions in this
manual for wheel cylinder unit and expander unit removal
and service.
11. If there is no evidence of brake fluid leakage in the wheel
cylinder unit or expander unit, install new dust boots (if
necessary). Refit the tappet head and manual override
assembly to the wheel cylinder. Temporarily install an
elastic band around the wheel cylinder adjuster pistons
to prevent them form becoming displaced.
WHEEL CYLINDER AND EXPANDER
UNIT REMOVAL
1. Disconnect the hydraulic inlet hose and bridge pipe
from the wheel cylinder and expander unit.
2. If the expander unit is being removed at this time, remove
the parking brake chamber from the expander body
and backing plate (dirtshield). Refer to the vehicle
service manual.
3. Remove the fixing bolts that secure the wheel cylinder
and expander to the backing plate (dirtshield) and
remove the units.
4. Move the wheel cylinder and expander to a clean work
bench for service.
FIGURE 14 - DE-ADJUSTING ADJUSTER MECHANISM
CLOCKWISE TO
DE-ADJUST
PUSH DOWN
FIGURE 15 - WHEEL CYLINDER
SPRING & LOCATOR
ASSEMBLY
SEAL
GASKET
ADJUSTER SHAFT
ASSEMBLY
DUST BOOT
PISTON
MANUAL
OVERRIDE
WHEEL
TAPPET HEAD
TAPPET HEAD AND
MANUAL OVERRIDE
WHEEL ASSEMBLY