New Backhoe Control Valve Question

[rScotty]

Going with new valves is the best choice given the age of the machine. I think JD was using Gresen so a direct replacement is no longer available. Rich B1 is correct about the different spools. The JD manual shows that each spool had a different housing.

You can restore operability with aftermarket valves. You will have to fabricate brackets, and potentially make new lines. Also the backhoe will not operate as smoothly as it does with the OEM valve because of what Rich B1 noted above. However it will still work safely, just rough.

You will need a closed center valve capable of the full 23 gpm. Most likely your going to have to get a 25GPM valve.

Which JD manual is that? I know that JD published a lot of good FOM (Fundamentals of Machine) manuals on their various tractor systems. Is that the type manual you mean? I'd like to add a JD FOM on closed system hydraulics to my tractor library.

Why do you say it would need a valve capable of the full 23 gpm? Usually PS has a dedicated priority on a portion of the total flow, so that has to be deducted and doesn't leave a huge amount. As I see it, all that would suffer wiith a lower gpm BH valve would be some continuous high end backhoe speed - which most of us don't use often anyway. In a closed system the pressure reservoir handles any short term call for full flow & recharges quickly.

That takes us back to pressure. In a closed system, pressure is constant and the reservoir means that usable flow doesn't vary (much) with demand. Of course the old JD500 was only 2000 psi.. unless some idiot previous owner turned the pressure up in the last 50 years....Hmmm..... turning up pressure for more power and more problems should be easy for a mechanic type to do and would explain everything, btw. .....Includng the leaking O rings. A simple pressure check would answer that question.

rScotty

 

[LouNY]

Here is a link to Prince series 20 valves,
in their catalog and reference section you can find all sorts of information.
Prince Manufacturing Corporation > Products > Hydraulic Valves > Stack
Also they have people available to answer question and to help spec out a valve that will work and do an excellent job.

 

[rScotty]

Here is a link to Prince series 20 valves,
in their catalog and reference section you can find all sorts of information.
Prince Manufacturing Corporation > Products > Hydraulic Valves > Stack
Also they have people available to answer question and to help spec out a valve that will work and do an excellent job.

Nothing wrong with doing that and at least getting the information. But I wouldn't go another step without checking the pressures you have on the system now. That is inexpensive and easy to do - and determines what the next step should be.

I see no reason why a JD500 from the 1960s can't be stored to as good as new and for a fraction of what new ones cost. They were designed to do exactly that.

rScotty

 

[Willie B]

I'm not sure what is wrong with your valve. Could it be repaired by a competent hydraulic machinist, or a used valve from a salvage yard?
25 years ago I bought a JD 410 1973? model year. After an hour run time it hadn't power enough to lift the rear bucket & front bucket was very slow. It was eventually diagnosed as two sections in the backhoe valve were leaking internally, not broken or worn out, defective since new. Parts were unavailable from any source & John Deere offered a whole assembly I remember as $6000. close to the value of the machine.
New Hampshire Hydraulics sold me a 10 part component valve to replace it. $1400. The valve was narrower than the original, so joystick assembly wouldn't fit. Had it been steel I'd have cut it & rewelded, but it was cast iron. I built new of steel.
Fixed it, but by then I had needed a hoe & bought a Case instead. The Case was 4 wheel drive & a lot better for loader work, I sold the John Deere.

 

[Bentrim]

I would be very cautious replacing a backhoe valve without researching the original valve. Some circuit may use a reduced pressure relief valve in the original valve. To replace it with generic valve may overpressure some circuits and damage the hoe.
Check the packing on the piston in the cylinder if it leaks down, I would suspect it quicker than the valve.