Manitowoc 999 Service And Maintenance Manual

Reference Only
INTRODUCTION 999 SERVICE/MAINTENANCE MANUAL
1-34
Published 05-16-17, Control # 233-03
When front drum handle (9) is moved to neutral after raising
load, the PC disables front drum brake solenoid HS-16,
spring-applying front drum brake. When front drum brake is
spring-applied, the PC sends an output signal to shift free fall
enable solenoid valve HS-18 of brake/clutch valve manifold
(12), blocking flow to tank. As front drum brake/clutch pedal
is released, up to 3,000 psi (207 bar) hydraulic pressure
pushes against piston to start compressing brake/clutch
springs to release the brake/clutch. Hydraulic pressure to
piston is in direct proportion to brake/clutch pedal movement
as controlled by the PC. Front drum brake proportional valve
HS-17 pulsates on/off between brake and tank, depending
on PC command or back-pressure. Moving brake/clutch
pedal fully applies brake/clutch without slipping.
CAUTION
Brake/Clutch/Motor Damage!
Do not move a drum handle in either direction from
neutral while a load is free falling. Damage to brake/clutch
and/or motor drive system could occur. Stop the load with
drum brake/clutch pedal before moving drum control
handle in either direction.
Do not turn free fall off or turn off drum brake while a load
is free falling. Stop loads with brake/clutch pedal, then
turn free fall off or turn off drum brake.
FIGURE 1-23
SERVO PRESSURE FROM
TRAVEL CHARGE PUMP
HS17
HS22
HS18
HS23
5 GPM
MOTOR
MANIFOLD
PUMPS
HS19
HS16
FRONT
LOAD DRUM
BRAKE
COOLING
INLET
BRAKE
COOLING
OUTLET
PLUG
PRESSURE
PRESSURE SENDER
BRAKE/CLUTCH
LOW
SIDE
HIGH
SIDE
350 PSI
(24 BAR)
LOW PRESSURE PILOT
BRAKE
PAW L
A
B
HS20
X
FRONT LOAD DRUM PUMP
PUMP DRIVE
.06
X
B
A
ENGINE
MANIFOLD
SUPERCHARGE
GEARBOX
SENDER
3
11
3
14
3
15
3
12
3
13
3
15
3
16
3
3
3
5
3
1
3
2
3
4
999CSM1-123

Manitowoc 999 Specifications

General

Brand	Manitowoc
Model	999
Category	Construction Equipment
Language	English