Basic Tractor Hydraulics Featuring Ken from BoltOnHooks.com

Festus said:

Re: the spring pressure on the pressure relief valve…
When I read about folks here adjusting their max hydraulic pressure, are you altering how this spring behaves? Wouldn’t it require changing to a new spring rate?

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JD for the most part uses a screw and jamb nut setup on their PRV's, so to increase the PRV pressure you tighten the screw thereby increasing the load or "spring rate" of the spring. Some JD's (like the 790/3005) and other manufacturers (like Kubota) use a shim setup where you add in shims to do the same.

Here is a picture from the tech manual for my 3720:

Great video and topic, guys! Hydraulic video on tractors is something I haven’t seen anyone cover before. if I understand correctly, you are going to have a video testing the hyd psi of all the tractors between the two of you? If that is correct, will you be showing a chart of what the factory setting of the tractors should be? If you do, can you also research further and find out what the older compact tractors should be as well, as well as backhoes? My 46 backhoe squeals a lot and i need to test the relief on it as well. I know this sounds simple, but in reality, much more difficult to gather that much information. My JD dealer is fairly hush hush on giving out tech info tractor and backhoe information.

Thanks guys for a great topic and video!