jd448 dipperstick

[tony l]

Loss of pressure on dipperstick when pulling maybe 3psi pushing 2500+ psi changed hose to make sure hose was good .don't know what to try next?this is all new to me.

 

[J_J]

You may have blown a seal on the cyl piston.

Maybe nut on the cyl shaft has came off.

 

[tony l]

Tks for responding .I put a psi gauge on the hose that would go on the rod end and got 2500psi and had a gauge on the hose that would go on the head end of dipper and had maybe 3psi had tractor running and was moving dipper stick lever front and back checking psi

 

[J_J]

Did you shift the gage to the other port, and if not, you would read a low/0 pressure because the fluid from that port is going to tank.

You should have installed the gage in the IN port of the FEL valve.

The gage installed there will tell you the pressure for any hyd action you do.

 

[tony l]

I had a gauge on both hoses at the same time

 

[Farmerford]

I suspect that backhoe has port relief valves on some of the ports. You should be able to identify the port relief for the dipperstick; the relief is probably a screw in cartridge and may have an adjusting screw in the center of the hex nut that is used to tighten the cartridge. There may be a port relief on the crowd port only since that goes to the crowd cylinder base and creates the most force on the dipperstick. If there is a port relief valve on the dipperstick crowd circuit, it may be held open by trash or have a weak or broken spring. You shoud be able to check by removing the relief valve cartridge.

 

[J_J]

I agree with Farmerford with a work port relief held open by weak spring or debris.

 

[tony l]

I suspect that backhoe has port relief valves on some of the ports. You should be able to identify the port relief for the dipperstick; the relief is probably a screw in cartridge and may have an adjusting screw in the center of the hex nut that is used to tighten the cartridge. There may be a port relief on the crowd port only since that goes to the crowd cylinder base and creates the most force on the dipperstick. If there is a port relief valve on the dipperstick crowd circuit, it may be held open by trash or have a weak or broken spring. You shoud be able to check by removing the relief valve cartridge.

Thanks for the help I pulled the relief valve for the dipperstick took it apart and found a torn O ring put a new seal kit in it and checked psi works great thank you all for help