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TL49J
RAM NOT HOLDING UNDER LOAD
Releasing the controls must stop the cylinder movements.
•
It is not advisable to leave an extended ma-
chine unattended to for a lengthy period of
time.
•
It is normal to expect slight creep over time
however during normal operating conditions,
the ram should hold the load and not move
once the lock valve cartridge has closed. This
may take between 1-2 seconds after the direc-
tional valve has been returned to the centre
position. The pilot pressure holding the valve
open must be allowed to drain back into the
tank to allow the lock valve to seat fully.
When a cylinder is not holding the load in place, it is
critical to know which part from the following list has
failed.
•
Cylinder piston seal.
•
O/C valve (check valve)
• Emergency lowering cartridge (if fitted)
T
he efficient way of establishing where the failure is,
is by removing all the hoses to determine where oil
is leaking out from.
•
If leakage is from the emergency lowering
cartridge, clean or replace (#3).
•
If leakage is from the O/C valve, clean and
adjust the relief valve or replace (Check
valves are non adjustable and can only be
cleaned or replaced) (#1).
•
If the leakage is from the piston seal kit, re-
place. The leakage is possibly through
annular port which has no lock valve (#2).
DROPNOSE RAM
T
he dropnose ram is fitted with two O/C valves.
There are two ways to determine which component
has failed.
1. Remove all hoses to determine where the oil
is escaping from.
2. If the oil is escaping from the full bore side,
the full bore O/C valve must be faulty.
3. Slowly open the adjusting screw for the O/C
relief valve on the annular side.
4.
The piston seals have failed if oil starts to flow
out from the annular side and the cylinder is
starting to close up at an increased speed.
Replace the piston seals.
SERVICE AND REPAIR
Figure 3-6
: For clarity, the drawing shows
only one hose to each service. In reality,
there are two hoses. One for the platform
controls and one for the ground controls. Only
the emergency lower has one hose.
Figure 3-7
: Dropnose cylinder with welded
on block containing 2 adjustable O/C valves.
3
1
2
2
2
1
1
3
