John deere 300b hydraulic problems

[John deere Chris]

Hi I have a 1980 john deere 300b backhoe/loader. The hydraulics only work at full rpm and are somewhat slow.....I was told the pump sounded good. I am lost and need some help figuring out why the hydraulics are acting up. This is not just the loader, it is the backhoe and power steering. Once the engin is revved up, there is a delay in the movement of the loader. Then they begin to squeak up. As long as the rpms are at its full the controls work. Once the engin is returned to an idle, for about 5 minutes the hydraulic operations will work as should. Then slowly stop working. I changed all filters, drained hydraulic oil and cleaned the transmition screen which was coverd with black junk. Please help me! Thanks

 

[J_J]

I sent you a PM.

 

[Tx Jim]

I'd suggest checking hyd stand-by pressure which should be 2350 psi.

 

[John deere Chris]

How do I check the stand by pressure

 

[J_J]

I believe the standby pressure is at the IN port of every valve in a closed center hyd system.

Activate a valve and max out a cyl and you should see the pump pressure, assuming the cyl is good.

 

[Tx Jim]

Tee into the power steering supply line or any other high pressure hyd supply line

 

[Solly223]

What was the outcome? I'm having the same problem, please help!

 

[Tx Jim]

Solly223
Welcome to MTF
You probably would have more replies if you had initiated your own new thread. What type problems are you having on what model tractor?? 300B?

JD closed center hyd problems require "very good/thorough" diagnostic procedures not just component replacements to correctly solve hyd problems.