JD 410 Brakes

[Todd_B]

My dad just purchased a JD 410 backhoe [ we hope it's a good deal ].Every thing is great,but brakes don't work.The unit doesn't get delivered until tomarrow.What should I look for first.Last owner thinks proportioning valve.Is this good start?Oh yeah,it's a 1979,if that makes a difference.Thanks for any tips.

 

[CCer]

First, Isolate the problem. Remove one of the plugs from the top of the brake valve, it should have oil in it, filled by tubing or internal passage. If not, fill it with hydraulic oil. Bleed air from system, using bleed valves on top of the axle housing, next to the transmission case. Same procedure as auto or truck.
Disconnect the oil line at the rear axle housing, and cap the line. Each side. ( I often slip a small, philips-head, flat-head, countersunk-head, sheet metal screw into the tubing and thread the nut back onto the fitting a little to hold it and test) Test each pedal independently. Pedal should be solid. if not, problem is in the valve. If they are solid,
leak is in the pistons, seals, in the axle housing. That's a srart.