John Deere 300 b backhoe select hydraulic problem

[oldnslo]

Are you thinking about a CCLS hyd system? JD 300B doesn't utilize a pilot signal to put pump in stroke merely a drop in hyd pressure which allows pump pistons to be pushed back by springs against the already rotating pump shaft allowing pump to pump oil.

Yes I thought this was a CCLS system

Does this model have the priority flow control for steering. If the hoe is working then something is blocking oil from getting to the loader valve.

 

[Tx Jim]

Pull the return line on the rear and start the tractor.

May I ask which return line you're referring to pulling?

 

[medic0648]

I have a 301 and the hydraulic return for everything goes through a hose to the rear into the sump. I had a valve fail internally and it bypassed to the return. Nothing worked unless something down the line caused enough back pressure.

 

[Suzukibruce]

May I ask which return line you're referring to pulling?

Update. The backhoe is working but has slowed down. I changed the pump filter. It was torn and full of dirt. If I lift the loader with another loader it will stay only a foot off the ground. I believe I have air in the lines because all worked well until I had to take the fuel tank off for repairs. I am open to suggestions as to how best get the air out.

 

[Suzukibruce]

May I ask which return line you're referring to pulling?

Update. The backhoe is working but has slowed down. I changed the pump filter. It was torn and full of dirt. If I lift the loader with another loader it will stay only a foot off the ground. I believe I have air in the lines because all worked well until I had to take the fuel tank off for repairs. I am open to suggestions as to how best get the air out.

 

[Tx Jim]

Yes I thought this was a CCLS system

Does this model have the priority flow control for steering. If the hoe is working then something is blocking oil from getting to the loader valve.

Yes there's a priority valve but to my knowledge both backhoe & loader are supplied oil after oil leaves priority valve.

 

[Tx Jim]

Suzukibruce
Previous owner must not have changed other hyd filters very regularly. Did you ever check/clean hyd oil sump screen in the bottom of trans case????

 

[Suzukibruce]

Suzukibruce
Previous owner must not have changed other hyd filters very regularly. Did you ever check/clean hyd oil sump screen in the bottom of trans case????

You are correct about filter and fluid changes. The first thing I did 30 tractor hours ago was change both filters and pulled the inline screen behind the 4 inch rubber hose. What a job getting that hose back on. The oil is new hygard. I知 going to try blowing compressed air in the sump to see if I get a positive reaction with the loader. Other than that I have no other filters that I know of to change

 

[oldnslo]

The oil is new hygard. I知 going to try blowing compressed air in the sump to see if I get a positive reaction with the loader. Other than that I have no other filters that I know of to change

Blowing compressed air into the reservoir helps prime the pump but I doubt that you have an air lock to the loader valve. This is a closed center system so if the back hoe is working the pump is moving oil and this oil should also be available to the loader. Can you operate a function on the back hoe and loader at the same time? If the hoe stops working this would point towards a problem in the loader valve circuit dumping oil to tank.

 

[Suzukibruce]

Yes I tried holding the loader in the up position while operating the backhoe.when the backhoe bumps the loader will move a little. I forgot to mention that before all this happened I lost the accumulator input hose. This is probably the problem. Again sorry for omitting this. I didn’t think of it at the time.