Jd 300b hydraulic pressure

[Boobakar]

My 1978 jd 300b ran good until hydraulic fluid just pushes out of control valve on bucket loader controls. Roght to the right side of steering wheel although fluid spits out opposite on those valve boxes??? How do I fix the pressure issue? I changed fluids and tranny and hydraulic filter elements, cleaned long side screen in center of tractor… thanks for any help!

 

[Jim.ME]

My 1978 jd 300b ran good until hydraulic fluid just pushes out of control valve on bucket loader controls. Roght to the right side of steering wheel although fluid spits out opposite on those valve boxes??? How do I fix the pressure issue? I changed fluids and tranny and hydraulic filter elements, cleaned long side screen in center of tractor… thanks for any help!

Unless it split the valve body, it is likely just a hose or O-ring, maybe a loose fitting. The first thing you need to do is figure out much closer where and what is leaking. Then maybe a picture(s) that show where the leak is, remember we cannot see it, you are the eyes of the forum looking at your tractor. Did you take anything apart in that aera in doing your service work?

 

[Boobakar]

I rechecked fittings and not sure why pressure built up so much. It will just stream out of where I drew those red arrows. They are 2 round heads and move up when fluid is released… thanks for your input and quick reply!

 

[Jim.ME]

I rechecked fittings and not sure why pressure built up so much. It will just stream out of where I drew those red arrows. They are 2 round heads and move up when fluid is released… thanks for your input and quick reply!

Those would appear to be the check valves. They have O-rings and backup rings on them and there are also some small parts inside associated with them. I expect you need to remove the loader control valve to work on them. The Tech manual for your 300B will have info on repair of the valve and also how to check the pressures. The John Deere manual publication number is TM1087. If you do not have a copy this site has a reprint of TM1087, for about $100 and eBay is a place you might find a good used OEM John Deere TM1087 tech manual.

 

[Boobakar]

Those would appear to be the check valves. They have O-rings and backup rings on them and there are also some small parts inside associated with them. I expect you need to remove the loader control valve to work on them. The Tech manual for your 300B will have info on repair of the valve and also how to check the pressures. The John Deere manual publication number is TM1087. If you do not have a copy this site has a reprint of TM1087, for about $100 and eBay is a place you might find a good used OEM John Deere TM1087 tech manual.

Could there be another reason for those to blow fluid out besides bad prints, etc??? Thanks again!

 

[Jim.ME]

Could there be another reason for those to blow fluid out besides bad prints, etc??? Thanks again!

Possibly but since they were blowing oil the way you described I expect the sealing parts have been compromised and need to be replaced in any case. Do the pressure checks called for in the manual and see if you find any over pressure points that could have affected them. Did you change any adjustments when you did the fluid and filter changing you mentioned?

 

[Boobakar]

See these the correct valve diagrams? If yes, how do the valves actually pop out?

 

[Boobakar]

See these the correct valve diagrams? If yes, how do the valves actually pop out?

No other adjustments made:: I hope

 

[Jim.ME]

See these the correct valve diagrams? If yes, how do the valves actually pop out?

You posted a picture of a fast-acting relief valve that threads into a Backhoe control valve, not the same and nothing to do with the check valves in your loader control valve.

I don't know for certain but I think one of the bolts that goes through the loader valve body passes through a slot in the side of the check valves to hold them in. That is why I said i thought the valve needs to be removed to fix it. When you study the manual's info on the loader control valve, it should tell you.

 

[Boobakar]

Will check all that now! Thanks!