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TL49J
GROUND CONTROL VALVE
This valve is identical to the platform control valve
except
•
It is not possible to operate the platform slew
from the ground controls. On the ground con-
trol valve schematic shown in Figure 3-10, the
last spool is that of the platform slew.
•
A high pressure carry over plug has been
fitted to the ground control valve to allow oil
under full system pressure to pass through
it. Without the internal plug, it is impossible
to operate the platform valve as all the oil will
flow directly back to the tank.
If it is necessary to operate the ground control valve,
make sure the carry over plug is fitted. The plug is
found inside the valve under the fitting for the return
line. Shine a light down the port to make the Allen
head grub screw visible. If not in place, use the
head grub screw fitted to the replacement valve.
Incase of an oil leak from the valve block, it is most likely to be from the end cap. This refers to either
the end where the lever is or at the opposite end where the return spring is. Never fully withdraw
the spool. Push it out opposite to where the leak is coming from with sufficient space to clear the
“O” ring which can now be observed with a small screw driver. Apply plenty of grease and keep well
lubricated when pushing the spool back in. If the spool is not centring, check that the return spring
and the end cap is well secured.
DIVERTER VALVE
When the diverter valve is not activated (no power on
the coil), the oil will flow to the outrigger control valve.
When activated, the oil flows to the ground control
valve. Incase of a reduced flow and a high pres
-
sure drop over the valve, the valve could be sticking.
Remove the cartridge from the aluminium body and
clean. Also look for contamination in the valve or
valve cavity.
To check that power is reaching the coil, hold a
screw driver against the end of the coil. When the
SERVICE AND REPAIR
Figure 3-9
: A view of the platform controls and check valve location.
Figure 3-10
: Ground control valve.
Figure 3-11
: Diverter valve schematic.