
Operation
Functional Description
The HS control consists of a ported housing mounted on a multiblock. External variable signal pressure
fed to port X1 is routed to the 4-way valve. As signal pressure shifts the 4-way valve it ports pressure to
the ends of the servo piston changing motor displacement. A threshold spring and ramp spring(s) act on
the opposite end of the 4-way valve.
HS Schematic
n
T6
T2
T1
T7 T8
T3
T4
U6
U7
T5
max.
disp.
A
L2
M4
M3
N
M1
L1
M2
M7
X1
M5
XA
XB
B
P106 417E
Control
Multiblock
PCOR Valve
BPD Spool
Shuttle
Loop Flush
4-Way Valve
Repair
Disassembly
1. Using a 4 mm internal hex wrench, remove screws (M10).
2. Remove the HS valve housing from the multifunction block.
3. Remove and discard O-ring (M12).
Service Manual
Series 51 Hydraulic Proportional Controls Service Manual
HS Control
11009446 • Rev BA • July 2014
21