JD 300 hydraulic puzzle

[tezjohnson]

My dad has a 1973 JD 300 industrial with loader ad 3-pt hitch. The loader worked ok when it was really cold (Nebraska in January) but got weak when the system was at operating temp. He installed a rebuilt pump (the exterior one in front of the engine). Now the loader only works when the steering wheel is turned and even then it is weak and chatters. same with 3-pt hitch. What should he do now? How do we bleed the system? Any help is appreciated. Tim Johnson

 

[beenthere]

Welcome to the forum.
Just within the last 2-3 weeks, there was some good discussion on a hyd. prob. with the 300 (am sure it was a 1973 too). Some very knowledgable responses that may help you sort throught your problem.
So, do a search and see if you can find the threads.

 

[true temper]

Sounds to me the priority valve is stuck. If your power steering is working fine that should be the problem. The valve is located under your right foot. If I remember right it is above the trans. oil filter takes a 9/16" wrench, has a couple of steel lines going to it. Pull it off and check to see if the spool is stuck. You might also check the steering valve, sometimes the O rings in them go bad. to check the steering valve run the tractor for tem minutes or so, if the steering colum gets warm you have problems in there.

 

[true temper]

You don't need to bleed the system. You are not building pressure.

 

[mmurphy]

Here in hydraulic section go a couple pages back and you will find "JD 301 hydraulics are dead" started by jeep67. System should be close enough to troubleshoot yours.