Hi Guys looking for alittle help here, The other day we took the Vavles apart that control the front bucket of the backhoe. For several months now I couldn't lift the front end up with the bucket or not very well so we figured the o-rings in the vavle or resolvers where giving out. Well the other day loading a dump truck it didn't lift very well either, so I figured time to put it in the shop and take the vavle apart. So they took that vavle apart and yes the O-rings were shot but the Resolvers were still in good shape. Ok now the mechanics put the vavle all back together and put it back on the backhoe, But now non of the Hydraulics are working, including the steering. We Called the cat Dealer today and they gave us some test to run on the pump to see if its putting the correct pressure out, but the pump's not putting any pressure out at all. The Pump was working just fine before we took the vavle apart but the Cat dealer thinks the pump might be shot. Could it be something Else? I would apperciate and Ideas. Thanks
Ok we just took the Hydraulic pump off and took it apart and the pump is just fine, so now we know its not the pump. any help would sure appreciate it.
Go back to the valve you where working on and look for a problem, something is out of place I think. Later Bob
You might have air in the resolver circuit. Loosen the signal line where it joins the pump regulator and work the function furthest away.
Ok thanks for the info I'll try that and see if there's air in the resolver circuit. the serial number for this machine is 5yj01975
I was reading on another post for a case backhoe which says the following: On the relief valves on the backhoe control valve, you can replace the lower and top seal O-rings while you have them out doing the load checks. If you disassemble the relief itself the adjustment for the pressure may/will need to be rechecked. To recheck the relief a test block is used to screw the relief into and the nut and screw is loosened, a portable hand pump is used to pump the relief to its spec pressure by turning the screw until in spec, then tighten the locknut back. This can also be done using the hand pump hooked into the hyd port/line on that relief (like bucket out) you would pump the hand pump watching it's pressure gauge. Say you needed 2500psi on that relief, you pump away and only have 2200psi, you would turn the adjusting screw in until the pressure would build to 2500psi. It is important to put the relief back in the same port, poor machine operation, heating of oil, lack of lifting pressure/holding pressure, bent rods, tubes, blown hoses are just some of the issues you can cause. Is this something that I would have to do to My Cat backhoe?