Lull 6K Service Manual - Manual (Page 602)

Brakes
9-28 Service Manual — Models 644B, 6K, 844C, 8K, 1044C, 10K
Park Brake
Fig. 9-16: Park Brake
The park brake is a drum type located on the output shaft of the
transmission (see Fig. 9-16). The park brake cylinder, cylinder mount, and
linkage assembly is located on the transmission behind the valve plate.
The hydraulic cylinder has an internal compression spring that actuates
the park brake.The park brake control is located beneath the instrument
panel in the operator compartment.
When the valve handle is pulled out, hydraulic pressure is routed to the
cylinder. The hydraulic pressure overcomes the spring force and the park
brake is engaged. When the handle is pushed in, the hydraulic pressure in
the cylinder is released to the return side of the hydraulic system. The
spring force in the cylinder then releases the park brake. In the event that
hydraulic pressure is lost, the park brake can still be set.
Two versions of park brake cylinder mounting and linkage assemblies are
described in the following pages. The version used in early production (see
Fig. 9-21 under “Cylinder Removal” below) has a brake cylinder mounted
horizontally. This version includes a cylinder that has 200 pounds of spring
force when the rod is fully extended, a maximum hydraulic retract of 500
psi, and a 2” bore by 2” stroke single-acting spring extend. It has one
grease fitting that requires weekly lubrication (see Fig. 9-21, Item 22).
0
80
60
40
20
-20
1
V
1078
Parking
Brake Control
Park Brake
Cylinder
Drum Brake
H1007