Brake Assembly Repair 1800 YRM 1005
REPAIR
If a brake assembly is malfunctioning, the cause may
be electrical, mechanical, or a combination of both. If
the brake electrical system is functioning correctly, the
brake should release with one solid "click" when ener-
gized. The brake coil is a large 24 V coil that acts as an
electromagnet to pull the armature plate away from the
friction disk. If the brake coil is too weak to compress
the brake springs and release the friction disk, the brake
must be replaced.
1. Disconnect the brake wiring harness (if brake is in-
stalled to truck).
2. Check voltage to the brake using a voltmeter.
a. Turn the key switch to the ON position.
b. Place the control handle arm in the BRAKE
OFF position.
c. Lightly rotate the directional controls to activate
the brake coil circuit.
d. Touch each lead of a voltmeter to each side
of the MAIN WIRING HARNESS connector
where the brake wiring harness connects.
e. Voltage to the brake should read approximately
24 V.
3. Check the resistance of the brake coil using an
ohmmeter.
a. Touch each lead of the ohmmeter to each side
of the brake wiring harness connector.
b. If the brake coil resistance reads between
30.24 and 27.36
(ohms), the brake coil is
functioning properly.
c. If the resistance reading falls outside the spec-
ified range, the entire brake assembly must be
replaced.
If the brake mechanical functions are not operating
correctly, the brake will not hold a fully loaded lift truck
on a 10% grade. The brake is NOT ADJUSTABLE and
must be replaced when it will not hold to specification.
If removing the drive motor assembly from the lift truck,
visually inspect the brake. Use a feeler gauge to check
the gap between the brake coil and armature plate in
several places around the brake to determine if the
brake is near the end of normal service life. Proper air
gap measurements range from 0.2 to 0.6 mm (0.0078
to 0.024 in.). See Figure 6. The brake must be replaced
if it no longer meets the proper air gap specifications
or if otherwise malfunctioning. The brake hub and the
brake assembly can be replaced separately. However,
if there is damage to the brake hub, there is most likely
damage to the brake assembly.
1. BRAKE COIL
2. AIR GAP
3. ARMATURE PLATE
4. FEELER GAUGE
Figure 6. Brake Assembly
6
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