Disc Brake Operational Test; General; Operational Test - Manitowoc 2250 Service Maintenance Manual

HYDRAULIC AND AIR SYSTEMS

DISC BRAKE OPERATIONAL TEST

General

There is no physical way to check the disc brakes for travel,
boom hoist, luffing hoist, front/rear drums, and swing. An
operational test of each brake must be performed weekly.
See Figure 2-17 for brake and brake solenoid valve
locations.

Operational Test

NOTE: For all pumps, the system pressure is preset at 379
to 448 bar (5,500 to 6,500 psi).
The electrical plugs at the brake solenoid valves must be
disconnected to stall crane functions during tests.
CAUTION
Overheating Hazard!
Avoid equipment damage due to overheating system
components.
Do not hold any function on stall for more than 10
seconds.
1. Start the engine and allow it to idle at 1,500 rpm.
2. Select and confirm SETUP mode (faulty pressures will
be recorded in any other mode).
NOTE: For load drums, make sure the crane is in Full
Power mode.
3. Disconnect the electrical plug for the brake being
checked.
4. Scroll to the corresponding diagnostics screen for the
brake being checked. Monitor PUMP PRESSURE and
PUMP COMMAND while moving the control handles.
5. For all functions, move the control handle in both
directions, one at a time, to check brake operation in
both directions.
6. Slowly move the handle for the function being checked.
The specified system pressure must be reached before
50% pump command is reached, and the brake must not
slip.
2-14
Avoid death or serious injury. Loads could fall or the crane
could move if the brakes are not operating properly.
If any disc brake slips when an operational test is
performed, repair or replace the corresponding brake
before placing the crane back into service. For load drums
with a disc brake on both ends of the drum, repair or
replace both disc brakes.
See the planetary manufacturer's manual for disc brake
repair instructions.
7. Reconnect the electrical plugs at all brake solenoid
valves at the completion of operational tests.
8. If disc brakes were repaired or replaced, retest the
brakes before operating with a load.
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Published 07-19-16, Control # 249-01
2250 SERVICE/MAINTENANCE MANUAL
WARNING
Falling Load/Moving Crane Hazard!
Figure 2-17
Description
Travel Disc Brake Solenoid Valve (both brakes)
Luffing Hoist Disc Brake Solenoid Valve
Swing Disc Brake Solenoid Valve
Luffing Hoist Disc Brake
Luffing Hoist Planetary
Case Drain Port
Swing Brake (disc)
Swing Planetary
Front Drum Disc Brake Solenoid Valve
Right Rear Drum Disc Brake Solenoid Valve
Left Rear Drum Disc Brake Solenoid Valve
Load Drum Planetary
Case Drain Port
Travel Disc Brake (qty 2)
Case Drain Port (qty 2)
Crawler Input Planetary (qty 2)
Boom Hoist Planetary
Boom Hoist Disc Brake
Case Drain Port
Boom Hoist Brake Solenoid Valve
Electrical Plug (typical)
Boom Hoist Planetary Fill Sight Gauge