I have this Ginma 304 Tractor with loader and backhoe. The backhoe stopped working. I removed the Relief valve and found a broken O-ring which I replaced with a generic O-Ring. Put things back together. Worked just a minute and quit! The problem is the relief valve. My question is 1- Are O-Rings specific (size, width, strength, etc)? If not where can I get a rebuilt kit for it? 2- How can I adjust the pressure on the relief valve. Did not notice an adjusting screw? Any help is highly appreciated. Thanks
oldnslo
Super Member
Yes O-rings are made to specific sizes and there different materials or compounds used for use with various types of fluids.
Possible a piece of the old O-ring is holding the valve open.
Don’t just randomly start adjusting the relief valve without installing a pressure gauge so that you know what the pressure is.
Possible a piece of the old O-ring is holding the valve open.
Don’t just randomly start adjusting the relief valve without installing a pressure gauge so that you know what the pressure is.
oldnslo
Super Member
Not sure where you are located but there are O-ring kits available online. I suspect that those are metric sizes. Typically sizing is Inside Diameter and cross section (thickness) of O-ring. For regular hydraulic oil nitrile (Buna N) or Viton - FKM are both acceptable compound materials.
The cap may come off that adjustment stem but could be wrong on that.
That appears to be a pilot operated relief so make sure the small pilot orifice in the spool is open and that there is not contaminates on the seat or pilot pin.
The cap may come off that adjustment stem but could be wrong on that.
That appears to be a pilot operated relief so make sure the small pilot orifice in the spool is open and that there is not contaminates on the seat or pilot pin.