Gradall 534B (9103-1390) Service Manual - Manual (Page 50)

HYDRAULIC SERVICE BRAKES
Brakes for the 534B are provided at both of the front
wheel hubs. Each wet disc brake is fitted with a
service brake port (P) and a park brake port (D).
When the service brake port (P) is pressurized,,the
service brakes are applied. When the park brake port
(D) is open to dump, the park brakes are applied.
WET DISC BRAKES
This illustration shows the inside of the wet disc
brakes. The discs are set and brakes applied when
pressure is applied thru port
(P) and moves the piston
(A) The spring (S) also sets the parking brake when
the drain port (D) is open to dump.
SERVICE BRAKE APPLICATION
When the operator presses down on the brake pedal,
the service brake valve
(D) is actuated, routing oil to
the wet-disc brakes (G) on both of the front axle hubs.
When the pedal is released. the oil is routed to dump
from the disc brakes and the brakes are off.
PARKING BRAKE APPLICATIONS
When the pilot circuit is not pressurized or when the
parking brake knob
(E) is pulled up, the springs in
the wet disc brakes close on the discs and lock the
front wheel hubs.
When the system is pressurized and the park brake
knob
(E) is pushed down, oil pressure routed to the
wet disc brakes where the springs are compressed
and the brakes are released.
9
PARKING BRAKES
SERVICE BRAKES