John Deere 300B hyd. pump question

[Jallcorn]

Have recently inherited an older JD300B w/ loader, no backhoe but does have 3 pt hitch. When running, I can hear a noise from the hyd pump in the front when NOT under load. I'm not a mechanic so all help will be appreciated.

Put under load and noise goes away.

W/ load or not, the 3 pt will raise and lower by itself a couple of inches regardless of height setting.

Turn the hyd pump shut off screw IN and the noise will stop (this shuts the pump off), turn the screw back OUT (normal position) and noise starts again.

Sometimes when the bucket lift lever is depressed to raise bucket, nothing happens or you get a jerky action from the bucket, arms, etc. This is not ALL the time, just some of the time.

Sounds like there is something possibly in the pump or somewhere else that is obstructing flow of fluid at times, might be something broken in the pump?? I don't have a clue where to start looking.

Thanks.
Email me at jballcorn@gmail.com with your thoughts.
James

 

[mmurphy]

I would say the noise you are hearing is because of a radial type pump. It is also probably a closed center system. (Hence the radial pump)When system pressure is reached pump is taken out of stroke. As far as noise, it is hard to go by sounds like, but they tend to be quiter when something is activated like a loader. The jerkiness could be from air, or an accumulater (cylinder shaped object down probably by your right foot) that needs replaced, or serviced. Not a typical DIY project.
It really is not a good idea to adjust settings on that pump with out any manual.

 

[Jallcorn]

I talked to a fellow SE of Memphis whose business is rebuilding hydraulic pumps for this type of tractor. he said the noise would not likely be the pump itself (or it would have self-destructed), but probably was the connecting shaft between the pump and the engine. Said there are 2 bolts that hold it in place and keep it tight and they will occasionally get a bit loose and can make a noise when not under load. Loaded, the noise goes away.

So I will attempt to locate the shaft/bolts, etc. and tighten same and see what happens.

he also said there was a screen in the transmission itself that screens oil from the transmission pump to the front pump that occasionally will get a bit of trash, etc. and restrict flow. Remove a plug, remove screen, clean and replace. i will look at that too.

That's all I know at this moment, but at least it is a starting point.