Bobcat 743 hydraulic question

[bgarner]

I have a bobcat 743 that I recently got. The transmission warning light is on. It had normal hydraulic fluid in it before i got it. I have drained the tank once and replaced the tank with 10w-30 motor oil like my manual calls for. The machine operates as it should but every 20 minutes of running it will make a very loud noise when operating the lift cylinders. I idle the motor back and it goes back to normal like it should be. It only happens with the lift or tilt, never when moving the wheels. Is there anyone who has any suggestions on what is the problem?

 

[wbecker]

Are you at the limit of lift or tilt when this happens?

 

[bgarner]

Are you at the limit of lift or tilt when this happens?

No it happens even with no load at all

 

[7LBSSMALLIE]

No it happens even with no load at all

port relief anti cav needs looked at. catch it before it explodes and you chasin down the rabbit hole looking for the checkball. seriously . check portrelief anti cav.

 

[bgarner]

port relief anti cav needs looked at. catch it before it explodes and you chasin down the rabbit hole looking for the checkball. seriously . check portrelief anti cav.

Where exactly is this port relief anti cab and what am I checking for

 

[Tazza]

Where exactly is this port relief anti cab and what am I checking for

I'm wondering if it could just be air in the system. Hard to know without hearing it myself.

 

[bgarner]

I'm wondering if it could just be air in the system. Hard to know without hearing it myself.

Wouldn't the air bleed itself out eventually?

 

[Tazza]

Wouldn't the air bleed itself out eventually?

It will self bleed, but if there is a crack or leak, it is possible that air can be drawn in. Even a plugged filter can cause it.

 

[billrbg]

It will self bleed, but if there is a crack or leak, it is possible that air can be drawn in. Even a plugged filter can cause it.

On my 743, the system "self-bleeds" in just a few seconds.

 

[rodbuilder]

Where exactly is this port relief anti cab and what am I checking for

It IS air. That's what cavitation is.