873 Aux Hydraulics inop

[CentralIA8965]

I have a 1999 873 F series. I've never used the aux hydraulics but recently got a backhoe attachment and can't get the aux to work.

Initially, the fuse was blown and the 2 green lights at the top right would not come on. I replaced the fuse and got the 2 lights to come on.

Then I tested the quick connects at the coils with a test light. There is power to the coil connections when I press the right hand controls.

I tested the coils and got 0.002 ohms on a 2k resistance setting. So I replaced both coils and cleaned the stems.

I turn the machine on, lower the bar, press the "Traction Lock Overide" green button at the top left and hear a click, then press the Aux Hydraulic button on the top right and get a green light (2 green lights if I press twice) but do not hear a sound. Then when I press any of the buttons on the right hand controls, I don't hear any engine RPM change and it doesn't act like anything is engaging. I get no movement at the aux hydraulic ram attachment. I have checked hyrdaulic fluid level and it's at proper level.

What else am I missing?

 

[CentralIA8965]

I was able to figure it out so I'll post the solution for anyone that may have the same problem in the future.

Essentially, the auxiliary hydraulics have a coil that goes over the stem. When you press a button on the handle to activate the hydraulics, it sends power which magnetizes the coil. The magnetized coil then causes the valve on the bottom of the stem to open and forcing hydraulic fluid into the auxiliary hydraulic lines. The issue here is that the valve was not opening up and sending hydraulic fluid. I removed the stems/valve, blew them out with an air compressor and soaked them in diesel fuel overnight. They still did not work. I figured I had nothing to lose so I soaked them in penetrating oil, put a ton of heat on them with a torch then used a punch and hammer to manually move the valve/spring inside.

I reconnected the valve/stem/coils and everything works like a charm now. I'm assuming these get siezed up from prolonged periods of not being used and contaminates in the hydraulic fluid. Once you know what it is, it's not hard to fix.