Posted by Paul (in NY) on Friday, September 22, 2006 at 11:10AM :
In Reply to: pto's posted by Dana (in Ma) on Friday, September 22, 2006 at 6:11AM :
There are many different hydraulic pumps, ie; Gear, gearoller, disk, disk valve. vane and piston to name some. All have a defined in and out port. I use gear pumps. The oil enters into the gears and exits past a very tight tolerance plate (thousands of an inch clearance) where pressure is built. On a gear pump, I can see no direct internal damage resulting from running in reverse direction, however, I dont see how it can build pressure, unless it of a special design to run both directions ( bi- directional).
With this said, may I suggest you consider the following. Your dump bed pump is no doubt a large displacement pump to provide quick dump of the bed. I would break the discharge line right at the dump bed pump and install an 'CENTER OPEN SPOOL' valve with 2 outputs. The out of the pump would go into the Flow IN on the center open spool valve. The main flow output from the valve would then connect to the line going to the dump control (this is the line you unhooked from the pump).
With the center open spool valve in the center position, all hydraulic oil is just passed thru the valve, its like it is not in the circuit. Your dump controls will work as normal.
Take both output lines from the center open spool valve and connect them to your hydraulic motor that turns your winch. Now when you pull the center open spool valve handle, the flow of oil to the dump controls is shut off and diverted out one of the center open spool valve discharge ports to your motor, the other line acts as the return line from the motor back to the system flow . Push the handle on the center open spool valve and the circuit is reversed with the motor now turning the opposite direction. This way you can power the winch in or out. You can swap the output hoses to the winch motor so a push or pull on the control handle will run the motor in the direction you wish.
You will NOT be able to DUMP and WINCH at the same time with this setup. Basically this is exactly the way I have my Carryall set up and will do the M37 the same way. My difference is that I am using the PS Pump to drive Hydroboost, Power Steering and Winch.
You can get a CENTER OPEN SPOOL valve from Northern Hydraulics. I bought a Prince Valve that contains a adjustable pressure relief built in the valve. If I remember back to 2004, the valve was about 60 bucks and a few bucks for high pressure hydraulic hose and your all done. Remember any fittings used to plumb the system MUST be STEEL FOR HYDRAULIC. If you use anything else you may end up pulling pieces out of your body OUCH !!!! The main flow IN/Out of the center open spool valve MUST be of the same size as the output of your dump pump so you dont restrict the flow. The hoses running to the hydraulic motor should be 1/2". To operate the system, just engage your dump bed pump as usual and the select if you want to dump or winch
You can email me if you have any questions and want to get into more detail, or we can do a phone call.
Paul