I have a hypro drive. They may be an oem for raymarine.
https://www.hypro.co.uk/products/hyd...eering-system/
Removing the nut will allow you to pull the coil off the spool valve. No
oil should leak.
Even before that check the coil with an ohmmeter. Not sure what resistance I would expect but 10-100 ohms seems about right. If the coil is bad the most likely failure will be open circuit.
When the coil is energized there should be a magnetic field. A
price of
steel, ie a screwdriver, will let you test for that.
If the coil is good you will need to remove and clean or replace the valve.
I had to do this. My valve was intermittently sticking in the on position. Ugh. Wheel locked! Under power! In Boston harbor.
I disconnected the ram and fixed the problem.
This is what I did:
Close the valve where the hose leaves the fluid reservoir. Reopen when operating though.
Remove the cylinder from its mounts for better access. Leave all hoses attached.
Set up a bucket to catch dripping fluid.
Remove the solenoid coil.
Remove the spool valve (simply unscrew it. There are flats. )
I then cleaned the valve by spraying then soaking then spraying with wd-40. I also operated the valve using the solenoid and a couple of (fused) wires from 12v. You can see and hear the valve move. Click.
This reduced the stickiness.
I reinstalled the valve.
The problem was better but not gone.
I dug in further.
The fluid was filthy, had black and brown fine particles, and was discolored.
I learned that hydraulic fluid can oxidize over use and time.
I ended up replacing the valve and draining and
flushing and filling the system with new oil.
The problem was gone.
In short, check the solenoid. If that’s good, clean the valve. You might want to flush the fluid.