Q14-23. In the bottom-up method of bleeding a brake
disassembly, cleaning, inspection, reassembly, and
system, what is the portable tank called that
supplies the pressure?
Q14-24. What is the minimum period of time that an
overheated wheel brake assembly must be
Perform the disassembly in a clean working area.
allowed to cool in ambient air?
As you remove parts, place them in a clean container
for protection against dirt and damage. If the valve is to
BRAKE SYSTEM COMPONENT
be disassembled for a considerable length of time, the
parts should be protected from moisture. Note the
method of lockwiring for reference during the
LEARNING OBJECTIVES: Recognize the
reassembly process. Remove the end cap and the
various components of a representative brake
plunger assembly as a unit. Disassemble the end cap
system, such as valves, reservoirs, and
and plunger assembly for inspection, cleaning, and
swivels. Identify the operation of a brake
replacement of sealing devices. Remove the opposite
end cap and remove the slide and sleeve assembly as a
unit for disassembly.
Components of brake systems are not peculiar to
any one system. A given component will vary in shape,
size, capacity, and manner of operation (depending
upon the manufacturer), but the function remains the
Use P-D-680 cleaning solvent to clean parts.
same. In this section, we will discuss some of the more
Except for the slide and sleeve, remove stubborn
common brake system component maintenance
accumulations of dirt with a stiff bristle nonmetallic
brush moistened in cleaning solvent. Dry all parts with
low-pressure, dry, filtered air.
INDEPENDENT SYSTEM RESERVOIR
NOTE: The slide and the sleeve assembly are
Repair of this brake reservoir is limited to
precision lapped parts; they must be kept together as a
disassembly, cleaning, and replacement of high usage
matched set. You should take extra care to prevent
parts from a cure-date repair kit. These high usage
damage during maintenance.
parts consist of a new sight glass with its O-ring seal,
washer, and retainer; a new filter, packing, and plug;
and a new nameplate for the reservoir housing.
Using a strong light and preferably some
Clean the reservoir inside and out with P-D-680
magnification, inspect all parts for scoring, nicks,
cleaning solvent. Use a fiber brush on threads. Dry the
interior with clean, dry compressed air from a
cracks, burrs, excessive wear, corrosion, or damage.
regulated low-pressure source.
Carefully examine all packing grooves and lands for
burrs and damage. The chrome plating of the plunger
After the reservoir is cleaned and the cure-date
should be inspected for blisters, pinholes, flaking, or
repair kit parts have been installed, conduct a leakage
damage, and plating should be continuous. The sliding
test. This is accomplished by connecting a source of
surfaces of the slide and sleeve should be free from
25-psi air to the filler port and applying pressure. The
reservoir should then be submerged in a tank of water
scratches, burrs, or nicks. Inspect the seating edges of
for a minimum of 2 minutes. No leakage should be
the slide for sharpness and freedom from nicks and
burrs. Any damage to the slide and sleeve will
necessitate replacement of both parts of the matched
POWER BRAKE VALVE
assembly. The holes in the valve-actuating lever are
checked for elongation, and the roller that makes
Maintenance of these valves at organizational-
contact with the plunger is checked for smoothness and
level activities is limited to removal and replacement.
freedom from nicks and flat spots. Test springs for free
After installation, rig the valves. Make an operational
length and test length versus test load in accordance
check of the brake system in accordance with the
with the spring data table provided in the 03 manual.
MIMs. Repair of the brake control valve consists of