I have an old B20 with a BT750AR backhoe (http://www.tractordata.com/backhoe-loader/000/1/3/130-kubota-b20.html). The backhoe has a auto return feature which is electronical controlled. One of the electrical solenoids (yellow) came apart. I am not sure if the solenoid is the failure point or a symptom of another failure. The original control valve part number is 78621-63010. Due to the inoperable auto return function and age/wear, I would like to find a non-electric alternative. Any advice on where to start?