Perplexing Hydraulic Problem

J_J · Jun 29, 2011

Is that not the hex screw that is screwed into the PB port to close off the gallery to the tank port. It seems like if this screw come loose the flow would take the path of least resistance and most of the fluid would just bypass the PB port and go to tank. At a certain rpm, maybe some fluid would flow through both ports, but very little.

With the 3pt in neutral, the fluid would flow through both ports to tank, and when you activated the 3pt, you interrupted the flow, and all the pump flow went out the tank port.

Certain valves don't use this setup as the PB plug makes the seat and closes off the gallery.

J_J · Jul 1, 2011

Here is the hex screw in question. Page 13 item 3 Not saying this is the same valve, but could be.

http://www.princehyd.com/Portals/0/products/valves/LVManual.pdf

jinman · Jul 1, 2011

Since this thread began in 2002, this problem has shown up many times and is well-documented in the New Holland forum with photos and illustrations. As JJ indicates by pointing out the Prince valve, it's not isolated to New Hollands. The symptom is the FEL works, but nothing else in the hydraulic system after it. If you had a tractor where the FEL is not first in the open-center system, then everything before the FEL and the FEL would work.

wdchyd · Jul 1, 2011

Thanx Jinman and JJ......Good to know..!!

RetBFDLtE22 · Dec 5, 2011

Thanks J_J for posting the diagram...but I was hoping weekend warrior would've posted the actual pic of the valve and exposed allen screw for us, not so mechanical members.

J_J · Dec 5, 2011

If your valve has a PB port, and not being used, it will have a plug.

If you look in the PB port and see a threaded hole, that is where the hex screw goes to make the valve PB. If you see a hex screw, the valve has been converted to PB.

If this screw should come loose, you will lose PB and most of the flow will go to tank, and you will lose 3pt, or any other valve after the FEL valve.

Surplus Center - P-BEYOND & CLOSED CENTER PLUG 8 GPM MB VALVES

If you look in the PB port on other valves, you will just see another hole, and when you insert the PB plug, it is long enough to seal off the bottom hole and make the valve PB.

Surplus Center - 3/4" NPT POWER BEYOND SLEEVE PRINCE 660312004