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PROBLEM
Cylinder rod will not move
Slow cylinder shaft speed when extending or
retracting
Trencher will not dig or digs extremely slowly
Engine stalls during digging motion
Engine will not turn or stalls under low load
conditions
Leaking pump shaft seal
CAUSE
A - Broken driveshaft on pump
B - Engine/pump misalignment
C - Loose shaft coupling
D - Small gear section damaged
E - Gear sections damaged
F - Frozen or seized pump
G - Poorly positioned shaft seal
H - Pump check valve leaking
I - Plugged oil breather
J - Excessive pump inlet vacuum
K - Low horsepower / weak engine
L - Slow engine speed
M - Low relief valve setting
N - High relief valve setting
O - Damaged relief valve
P - High unloading valve setting
Q - Hydraulic lines blocked
R - Too little oil to the pump
S - Air in the hydraulic oil
T - Control valve leaking internally
U - Damaged control valve
V - Blocked control valve
W - Internally damaged cylinder
Troubleshooting
SOLUTION: A,C,E,O,Q,R,U,V
SOLUTION: E,J,L,O,R,S,T,W
SOLUTION: D,H,J,M,R,S,T,W
SOLUTION: K,N,P
SOLUTION: B,F,K,Q,V
SOLUTION: A,B,E,G,I
Return pump for authorized repair
Correct the engine/pump alignment
Correct the engine/pump alignment
Items D through H require repair of the pump by an authorized service
center
Make sure the reservoir is properly vented
Clean inlet hoses and free them of any leaks
Have engine serviced at an authorized service center
Have engine serviced at an authorized service center
Adjust while using a pressure gauge and with assistance of a
professional
Adjust while using a pressure gauge and with assistance of a
professional
Return directional valve for authorized repair
Adjust while using a pressure gauge and with assistance of a
professional
Flush and clean the hydraulic system
Add oil to the reservoir
Clean reservoir and add oil.
Return directional valve for authorized repair
Return directional valve for authorized repair
Flush and clean the hydraulic system
Return cylinder for authorized repair
12
SOLUTION
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