hey guys, I am working on a 420D and it seems like i have a resolver issue in the backhoe valve body does anyone have a diagram or an actual picture of the location thanks
There are 6 different models of 420D so start by posting a Serial Number. That enables info to be found. This thread might help you - HeavyEquipmentForums I know the symptoms are different to yours but the diagnostic procedure is the same whichever circuit is giving the problems.
sorry i forgot to attatch it TBLN01469
Each section of the control valve will have 2 resolvers in it. The illustration below shows the complete control valve and some sectional views of the valve for the backhoe boom (#3). The location of the resolvers in all five sections of the valve are all the same (#4 & #6), shown in Section B-B. Check for broken/missing O-Ring seals or stuck balls. If you find a ball stuck in the seat you can free it but it will jam again, basically the seat needs replacing.
ok thanks a lot
The trouble i am having is the stick in and bucket curl functions are slow until i operate any other function and they come to life i changed all the primary and secondary resolver orings, and it stayed the same any other ideas
Did you make sure that all the ball check valves in the resolvers were free to move.? The one in valve #4 that lies in between 4A & 4C is not visible. You have to shake the valve to hear it rattle. If it doesn't rattle immediately that indicates that it has hammered its way into the seat and that you need a new resolver assembly.
Resolvers are tested by operating the lazy function, and then, while the circuit is still lazy, operate an adjacent function, by looking at the flow chart. Read the chart from left to right on the top line, then on the bottom line. So if you are having problems with stick and bucket functions the problem resolver is likely to be one of the ones to the left of them in the diagram.
Let me check again