Loader 1972 JD 300 backhoe and loader-hydraulic problem
- Thread starter bpperk
- Start date
Folks, it is fixed. The original valve is a closed center valve in that the relief is set greater than the pump pressure. The replacement valve had the relief set too low and was not a closed center valve. So we added the feature that converts it to closed center and set the relief above the pump pressure. With your help we figured this out. What fooled us was that the valve when operated as open center labored the engine. That still does not seem correct, however without the closed center function the fluid runs through the valve to the return line and filter. One would think that fluid running without resistence would not labor the engine, but it did. Thank you.
MAYTAG MAN
New member
- Joined
- Nov 14, 2011
- Messages
- 22
- Tractor
- JOHN DEERE JD300
WOW...bpperk, you love your yellow iron as much as I do...and thanks to TX JIM, I am now very sure my faithful JD300 is a closed system.
The machine I bought last year runs but has some issues...which I shall go over at another time. But for now, what I had to do was put in a 2.2 ohm resistor in the wire to the coil because the wire apparently lost it ability to resist and the coil was throwing high voltage back into the battery. The multimeter showed over 20 volts spiking. I thought about this for a long time and finally tried an experiment. I took a piece of old heater coil wire from a burned out Maytag dryer and cut it to a length (approx 12") that made 2.2 ohms and cut the wire going to the coil and using clips, put the resistance wire in the circuit...voila, no more spikes and I'm sure the coil will run cooler and the points and condenser are probably liking it too. Hope that helps someone. Those old JD300 are nice...small but not too small...cute...when I start it, I destroke the pump with the little destroker valve and the engine starts so much easier.
The machine I bought last year runs but has some issues...which I shall go over at another time. But for now, what I had to do was put in a 2.2 ohm resistor in the wire to the coil because the wire apparently lost it ability to resist and the coil was throwing high voltage back into the battery. The multimeter showed over 20 volts spiking. I thought about this for a long time and finally tried an experiment. I took a piece of old heater coil wire from a burned out Maytag dryer and cut it to a length (approx 12") that made 2.2 ohms and cut the wire going to the coil and using clips, put the resistance wire in the circuit...voila, no more spikes and I'm sure the coil will run cooler and the points and condenser are probably liking it too. Hope that helps someone. Those old JD300 are nice...small but not too small...cute...when I start it, I destroke the pump with the little destroker valve and the engine starts so much easier.
zippo77
New member
- Joined
- Jul 9, 2012
- Messages
- 1
- Location
- stephenville, texas
- Tractor
- 1970 john deere 400 loader backhoe
1970 400 john deere loader hydraulic problem. I have a loader control valve problem. It was leaking oil so I took it to a supposedly hydraulic mechanic. He said he could not find parts for it. He charged me for working on it and when I got it home it was rough and had to manually pull and push the handle in and out of positions. Then it started leaking worse. I got tired of dealing with him. I needed the hoe so I went down to a tractor supply store and got a cheap control valve, probably 10 gpm. It was really slow. So when I got time I took the jd control valve apart and the bolt that when into the end cap was gone and replaced by a short bolt that did not even reach the end cap and had a different size spring on it. I guess he was pretty good because I can't even get it to work now. It squirts oil out the end caps and hardly moves. It has a 1500 psi and a 2500 psi relief valves in the bucket valve, and a anti-cavitation valve in the boom valve. I don't know anything about any of it. I think it says it is a 28gpm valves. I would like to find someone to rebuild it, but it will have to have a new spool or part of it any way., or if I could by a after market one that would work I would be happy. Is there any one out there that knows of a place that could repair this one or sell something compatibly to this one. I would really appreciate it a lot. Broke down in Texas. I don't use this hoe a lot, but like to have where I can.
wmaufschlag
New member
I am looking for a used hyd. loader control valve for a jd300b. It does not have to work I just need the bucket lift spool
if any one can help give me a call 1-908-500-8692 Bill
if any one can help give me a call 1-908-500-8692 Bill
Tx Jim
New Member
May I ask what you think you can do with a used spool. Spools & valve housings are matched and can't be interchanged.
wmaufschlag
New member
don't matter what I'm going to do with a used valve . cause I already found one without any bodies help and got it working again
Tx Jim
New Member
wmaufschlag
Congratulations I'm glad you got it going.
Jim
Congratulations I'm glad you got it going.
Jim