TM 5-3825-226-24
AIR CHAMBER AND MASTER CYLINDER OPERATION
AIR CHAMBER AND MASTER CYLINDER OPERATION
1.
Air chamber Inlet
4.
Air chamber assembly.
9.
Master cylinder
12.
Plate.
17.
Valve.
passage from brake
5.
Spring.
assembly.
13.
Cup.
18.
Cup.
valve.
6.
Supply passage.
10.
Master cylinder outlet
14.
Indicator.
19.
Spring.
2.
Diaphragm.
7.
Cap.
passage.
15.
Piston.
20.
Residual pressure valve
3.
Boot.
8.
Bypass passage.
11.
Rod assembly.
16.
Passages.
(check valve).
When the brake is pushed, it sends air from the
brake control valve through passage (I) to the air
compartment of air chamber (4), Pressure air will push
on the back of diaphragm (2) and rod assembly ( I 1 )
and move the diaphragm (2), rod assembly (I 1),
indicator (14) and piston (15) to the right. As piston (15)
moves cup (18) past bypass passage (8), brake fluid in
the master cylinder bore will go through passage (10)
and residual pressure valve (check valve) (20) to the
wheel cylinders.
When the brake pedal is released; pressure air is let
out of air chamber (4) and spring (5) moves diaphragm
(2) and rod assembly (I1) to the released position.
Diaphragm (2) and rod assembly ( 11) moves faster
than piston (15) because of the brake fluid which must
be removed. This will cause a reduction in the pressure
area between cup (18) and, residual pressure valve
(check valve) (20). Brake fluid ahead of cup (13) is
pulled through passage (6), passages ( 16),in. piston.(
15) and past valve (:17).
When the brake fluid moves back through residual
pressure valve (check valve) (20), spring (19) moves
cup (18)"and piston (15) toward plate (12). -
When piston (l ) contacts plate ( 12), bypass
passage, (8) is open to the master cylinder bore.
Residual pressure valve (check valve) (20) keeps a
small amount of residual pressure (back pressure) in the
brake hydraulic system. Cap (7) has passages to let air
pressure out of the master cylinder reservoir. The brake
fluid pushed
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