Cavitation

[TEKelly]

I recently purchased a White 2-135. When it first starts there seems to be no fluid in the hydraulic pump and it cavitation. Is there a check valve that prevents all of the hydraulic fluid from running back into the transmission? Or could it be something else?

 

[rrlund]

I'd have to look it up to be sure anymore, but I think that had a charge pump in behind the main pump didn't they?

 

[TEKelly]

I'd have to look it up to be sure anymore, but I think that had a charge pump in behind the main pump didn't they?

Not sure. I've been told to change the hydraulic filter and something about a screen in the rear end. Would really like to fix the problem before something happens to the pump. I was told the pump was changed. Would make sense since it's blue and not black like everything else.

 

[TEKelly]

I'd have to look it up to be sure anymore, but I think that had a charge pump in behind the main pump didn't they?

Thanks for trying to help.

 

[tom upton]

Yes they have a charge pump. Does it only sound lke it is cavitating after it sits for a day or so or does it do it if you shut it down and then restart shortly after? It could be the seal or an air leak on a suction line, but before I would tear into it especially since pump has been replaced and maybe new pump compensator not set correctly I would go that route first. Simply turn compensator screw counter clockwise a 1/4 turn or so to see if noise diminishes on start up. If it does then get yourself a guage to plug into a remote and someone who knows how to set it or read some of the old posts on compensator setting.

 

[TEKelly]

Yes they have a charge pump. Does it only sound lke it is cavitating after it sits for a day or so or does it do it if you shut it down and then restart shortly after? It could be the seal or an air leak on a suction line, but before I would tear into it especially since pump has been replaced and maybe new pump compensator not set correctly I would go that route first. Simply turn compensator screw counter clockwise a 1/4 turn or so to see if noise diminishes on start up. If it does then get yourself a guage to plug into a remote and someone who knows how to set it or read some of the old posts on compensator setting.

Thank you sir. I learn a little more every day.

 

[TEKelly]

Thank you sir. I learn a little more every day.

I'm not sure if it does it after setting for a short time since I have been afraid to run it because of this problem. Where is said compensator screw located? Perhaps I should aquire a manual. Is the charge pump an electric pump? Should I hear a noise from a pump when I turn the key on?

 

[tom upton]

I'm not sure if it does it after setting for a short time since I have been afraid to run it because of this problem. Where is said compensator screw located? Perhaps I should aquire a manual. Is the charge pump an electric pump? Should I hear a noise from a pump when I turn the key on?

No its not electric. Yes you should get a manual . Compensator is attached to the blue pump you were talking about with 4 socket head screws the adjstment screw is on the end of it. It may look like attached pic or it could be a small srcew with or without a jam nut on it or it could be a hex nut depending on vintage of pump that was replaced. If memory serves me correctly in some industrial applications they had a hex cover nut that you removed to access the compensater screw, but I doubt yours would have that.

 

[TEKelly]

9

 

[TEKelly]

This is what is on my pump

 

[TEKelly]

I loosened the jam nut and tightened it clockwise and it got worse. I backed it out counterclockwise and it seems like it's a lot better. I left it set for a couple hours and restarted it and it hardly cavitation at all ! Progress !!!

 

[tom upton]

I loosened the jam nut and tightened it clockwise and it got worse. I backed it out counterclockwise and it seems like it's a lot better. I left it set for a couple hours and restarted it and it hardly cavitation at all ! Progress !!!

Sounds a lot like it is just the compensator set higher or too close to the main relief. What you need now is someone who knows a bit about hydraulics that has a guage set-up to plug into a remote and get your compensator set at least 200 psi below the main relief valve. Probably a good idea to change out your filter that resides in the big canister to the left of your pump but please get a manual first as there is a procedure for changing out filter so as to not introduce air into system. Also there should be a small tin cap on top of the hydraulic housing at the back of tractor that acts as the breather for the hydraulic sump. Quite often the replaceable filter in it never gets changed and plugs solid with dirt not allowing sump to breathe. If its plugged it can cause cavitation.