30 | MDP Operation & Maintenance Manual
Symptom Cause Remedy
Jaw Speed wont shift when the jaws 
are partially opened.
Back pressure is too high in the base 
machine return line.
Use higher diameter hydraulic lines 
to minimize back pressure. Move 
the main spool adjustment screw 
clockwise in small increments until 
the issue is corrected (see “Adjusting 
the Speed Valve” on page 23).
Jaws continue to close after the 
operator has let go of the controls, 
after moving in speed mode. 
The main valve spool isn’t fully 
shifting out of speed mode.
Move the main spool adjustment 
screw clockwise,in small increments, 
until the issue is corrected (see 
“Adjusting the Speed Valve” on page 
23).
The jaws lack power.
The main valve spool isn’t fully 
shifting out of speed mode.
Move the main spool adjustment 
screw counter clockwise,in small 
increments, until the issue is 
corrected (see “Adjusting the Speed 
Valve” on page 23).
Base machine pressure is too low or 
is in hammer mode.
Check the base machine.