-4) Rust in motor. These motors are not rated to be outside of
a toolbox. And sometimes people clean the inside of the toolbox
with a high pressure water sprayer. Not recommended.
-5) Bent valve stem. Usually due to tools being thrown in
toolbox.
-6) Valve coils are not energizing. You can put a screw driver
to the top of the coil, push the button on the controller to see
if either valve is magnetizing. If either coil is not magnetizing, the
wires going to that coil may have a bad connection.
Contaminated hydraulic fluid potential problems
Hydraulic fluid cleanliness. The tolerances within a hydraulic power
unit are very tight. Therefore the cleaner the hydraulic fluid the
less chances for problems like sticking valves. Also, temperature
can play a factor. In colder temperatures the fluid can thicken
causing the battery to pull more amps causing more premature
battery related issues. We recommend transmission fluid for
most applications but especially cooler climates (ATF or Dextron
III). But it is also recommended that you filter the fluid before
putting it into your pump. But field application of this may be
challenging. Fluid contamination can happen a variety of ways.
46
When building the trailer and the hydraulics are first being installed.
Filtering the fluid is more practical. When making the hydraulic
hoses be sure to clean the hoses out after they have been
cut and crimped. If you are going to store the hoses before
installing them be sure to cap them off after you clean them.
Just sitting on the shelf waiting to be installed can potentially
introduce dirt. Then when installing the hoses, the installer needs
to pay careful attention that they do not accidently introduce
contamination. Such as dropping the end of the hose onto the
ground before attaching it to the pump or cylinder. Even if all of
these precautions have been done then there is still the potential
for internal contamination. For example: all of the pumps and
cylinders have been tested on a test bench at their respective
factory. Is the fluid on the test bench clean? On a rare occasion
a gear pump may pass all of its test but may still have a sliver of
aluminum that fails to break off after machining. Then it makes
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