MCi Crusader II 1989 Maintenance Manual page 151

Date
1-1-89 .
Page· ___
4-_2_1 _ _
MC-9 MAINTENANCE MANUAL
4
1
1. Body
3. Seal 5. Spring
2. Cover 4.
Spring
Retoi~er
6. 0-Ring
Figure 4-22. Air Line Check Valve.
When installing valve. make certain that it is installed cor-
rectly with respect to the desired air flow. An arrow indicating
the direction of air flow is cast into the body of the valve.
SERVICE BRAKE STOP LIGHT SWITCH
The stop light switch (figure 4-23) operates in conjunction
with the brake valve and stop light by completing the stop light
electrical circuit when a brake application is made.
When air pressure from the brake valve enters the cavity on
the side of the diaphragm. the diaphragm changes its position.
overcoming the force of the spring and moving the contact
plunger until the electrical contacts close. This closes the stop
light circuit. When the air pressure acting on the diaphragm is
exhausted by the brake valve, the spring forces the diaphragm
and the contact plunger back to their normal position and the
stop light circuit is opened. See figure 4-24.
Figure 4-23. Stop Light Switch Location in Front
Tire Compartment (1).
TESTING
Apply the brake valve and note that with the first downward
movement of the brake valve pedal or treadle. the stop light •
immediately lights. Release the brake valve and note that the
stop light goes off. With the brake applied. no leakage is permit-
ted at the stop light switch.
REMOVAL AND REPAIR
1. Disconnect electrical connections at the stop light switch.
2. Unscrew switch.
3.
Remove the cover from the body and lift out the spring
contact plunger, diaphragm ring, and diaphragm.
4. Clean all metal parts in cleaning solvent.
5. If diaphragm is cracked, worn or damaged. replace with
new diaphragm. ·
6. Inspect the contact points for signs of pitting or wear. If
pitting is not too severe. the contacts may be reconditioned by
filing them with a fine file such as is used for distributor points. If
they cannot be reconditioned, they should be replaced.
7. Check the spring for tension. If it has lost its tension, it
should be replaced.
8. 11 the body or cover is cracked or damaged, it should be
replaced.
TEST OF REBUILT STOP LIGHT SWITCH
Both operating and leakage tests. as indicated under Test-
ing, must be made after rebuilding or repairing the stop light
switch. The switch must meet the following specifications:
A. No leakage is permissible at the stop light switch with the
brake applied.
B. The stop light switch contacts should close at not more
than 5 psi (34.5 kPa) of air pressure.
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