Bush Hog CBH80 - Manual (Page 42)

1. OPEN-CENTER SYSTEM WITH LOADER VALVE
OR OTHER ACCESSORY VALVE CONNECTED TO
THE TRACTOR HYDRAULIC SYSTEM
When a loader valve or other accessory valve must
be connected to the tractor hydraulic system in addi-
tion to the backhoe control valve, a Power Beyond
Kit is required. This kit converts the backhoe valve so
that pressurized hydraulic oil can be directed to
another open-center valve for a loader or other
accessory. This allows the backhoe valve and the
other valve to be connected to the tractor hydraulic
system simultaneously, without the inconvenience of
using a flow diverting valve.
Since the Power Beyond Kit is used with open-cen-
ter tractor hydraulic systems, oil constantly flows
from the pump, through the backhoe valve and then
to the reservoir. See further in this manual for
instructions on proper assembly.
2. CLOSED CENTER SYSTEM: (CBH 60 & CBH 70)
Because a closed -center system requires no flow of
oil through the backhoe control valve when the
levers are in a neutral position, the CBH 60 & CBH
70 backhoe must not be connected to a closed-cen-
ter tractor hydraulic system.
IMPORTANT: Do not connect a CBH 60 & CBH
70 backhoe control valve to a closed-center trac-
tor hydraulic system, or serious damage to
backhoe valve or tractor hydraulic system may
result.
3.OPEN-CENTER SYSTEM WITH RETURN OIL
NOT REQUIRED FOR LUBRICATION -Figure 19
The pressure hose (A) should be connected from
the pressure port on the backhoe to the pressure
port of the tractor remote couplers or directly to the
tractor valve. The return hose (B) should be con-
nected from the tank (return) port on the backhoe to
a port on the reservoir, as shown in Figure 19.
IMPORTANT: Never connect the return hose to a
tractor remote coupler which can be pressur-
ized. Accidental pressurization can cause seri-
ous damage to backhoe valve.
4. OPEN-CENTER SYSTEM WITH RETURN OIL
REQUIRED FOR LUBRICATION - Figure 20
On some tractors, the return oil cannot be routed
directly to the reservoir because it is required for the
lubrication of other functions. Check this characteris-
tic with your dealer. The pressure hose (A) must be
connected from the pressure port on the backhoe to
the pressure port of the tractor’s remote couplers or
directly to the tractor valve. The return hose (B)
must be connected from the tank (return) port on the
backhoe to a surge relief valve as shown in Figure
20.
NOTE: The surge relief valve is not supplied with
the backhoe or mounting kit and must be ordered
separately to complete this type hydraulic hook-up.
Complete the hydraulic hook-up by connecting the
surge relief valve to the return port of tractor remote
couplers or directly to the tractor valve, and by con-
necting a hose from TANK port of the surge relief
valve to the tractor reservoir as shown in Figure 20.
The surge relief valve is used to protect the backhoe
valve from damage caused by accidental pressur-
ization or high back pressure build-up. If this hap-
pens, oil will be vented from the TANK port of the
surge relief valve to the tractor reservoir to prevent
loss of vented oil.
40
Figure 19 Figure 20
Backhoe Control
Valve
CBH 70 & 80
Shown
To Tractor
Reservoir
To Pressure Port
of Oil Supply Pressure
Coupler
Couplers
Backhoe Control
Valve
CBH 70 & 80
Shown
Pressure
To Pressure Port
of Oil Supply
To Tractor
Resevoir
To Return Port
of Oil Supply
Hoses Supplied
by Customer
Hoses Supplied
by Customer
B
A
B
A