Bendix Commercial Vehicle Systems AH-1B AIR HYD INTENSIFIER 4/04 - Manual (Page 7)

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FIGURE 10
5. Note and mark the orientation of the actuator and master
cylinder to the mounting bracket. Remove the two nuts
and washers from the mounting studs of the actuator
(use a 15/16" socket wrench). Separate the master
cylinder and actuator from the mounting bracket and
retain the actuator for later disassembly. CAUTION:
Piston under spring load and retained by the push rod
only when compensating tilt valve assembly has been
removed. (Refer to Figure 8.)
6. Remove the o-ring from the flange of the master cylinder
and the gasket between the bracket and actuator.
7. Remove the piston assembly and spring from the body
of the master cylinder. (Refer to Figure 9.)
Actuator Disassembly
8. Mark the relationship of the clamp ring, pressure and
non-pressure plates. Remove the two nuts and bolts from
the clamp ring of the actuator (use a 1/2" socket wrench).
Grasp the ears of the clamping ring and spread slightly
until ring will come off and pressure plate and
non-pressure plates separate. CAUTION: Parts are
spring loaded. Use a press or clamp to retain the push
rod and return spring during disassembly.
9. Remove the spring seat, spring, and boot from the push
rod and separate the diaphragm from the push rod.
(NOTE: Do not separate the diaphragm from the push
rod.) If the diaphragm is to be replaced, a new push rod
and diaphragm assembly will be required.
CLEANING & INSPECTION
1. Wash all master cylinder parts retained during
disassembly in clean DOT 3 or 4 brake fluid. CAUTION:
DO NOT use any solvent other than clean brake fluid
for cleaning or flushing master cylinder parts. The use
of unapproved solvents with a trace of mineral oil will
damage rubber parts.
2. Remove all sediment or foreign material from the bottom
of the fluid reservoir. If the reservoir is equipped with
filters, make certain they are thoroughly cleaned. If the
filters are thoroughly plugged and/or cannot be cleaned,
the entire brake system should be flushed. If the filter
cannot be cleaned, it may be removed after the system
is flushed.
3. Inspect the condition of the piston. Measure the major
diameter (around the top edge of the o-ring groove and
piston actuator lip) of each piston in several places around
its circumference. The difference between the largest
and smallest measurement on each of the diameters
measured should not exceed .005 inches (.13mm). If
the diameter of the piston varies more than the maximum,
the master cylinder should be replaced or repaired using
a maintenance kit.
4. Examine the master cylinder bore after cleaning. If pitting,
scratching or visible wear patterns are noted, the master
cylinder should be replaced. Dirt, gum and stained areas
not removed during cleaning can be polished with crocus
cloth. DO NOT USE EMERY CLOTH OR SAND PAPER.
Master cylinder bores may be honed provided that the
diameter is not increased substantially. Honing to remove
scratches and pitting will most likely increase the bore
diameter beyond the sealing ability of piston seals. To
make certain the bore diameter has not been excessively
increased, measure the piston clearance in the master
cylinder bore. Using a feeler gauge make certain the
clearance does not exceed .010 inches (.25 mm). Make
certain that no burrs or sharp edges remain in the cylinder
bore. Thoroughly clean and rinse the master cylinder in
brake fluid after polishing or honing.
5. Inspect the actuation push rod return spring for corrosion
and pitting and replace if necessary.
6. Inspect the actuator diaphragm for wear and abrading.
(It is recommended that the diaphragm be replaced
whenever a complete disassembly of the AH-1B
™
intensifier takes place.)
7. The push rod boot should be replaced each time a
complete disassembly is undertaken.
ASSEMBLY
Actuator Assembly
1. Install the boot onto the push rod assembly. The small
I.D. of the boot must be forced over the larger O.D. on
the shaft of the push rod. Place the spring over the
push rod and boot and place the spring seat onto the
spring. Force large flange end of the boot through the
center hole of the spring seat.