Backhoe M4900 backhoe keeps tripping the pto

[Rubicon1000]

Hi guys, I have a M4900 with a bradco 509 backhoe and here lately I can only get a couple scoops of dirt and the pto lever on the right side keeps kicking off.
The tractor only has 300 hours on it and maintenance has always been done.
The stabilizers seem to be moving slower than normal and I'm not sure if there could be air in the system somewhere? Any ideas on what might be causing it?
I'm not sure how to bleed the backhoe but the fluid levels are all good and the loader is working normal. Any ideas would be much appreciated. Dan

 

[Tx Jim]

Sounds as if hyd pressure is below spec's allowing pto control valve to disengage. How long since hyd filters were changed. I'll recommend getting a hyd gauge to check system pressure. Sorry but I can't remember what psi hyd pressure should be. By chance is feedback rod on 3 pt adjusted incorrectly allowing 3 pt valve to by-pass or is scv valve control handle not centered.

 

[Rubicon1000]

I'll be back out to the property this week and I'll check out your suggestions and see what I can find.
I'm probably going to go ahead and change the filters, I'm sure they are due for a change. Thanks for the suggestions. Dan