How to tell which direction a hydraulic pump rotates?

[unioncreek]

A friend gave me a Borg Warner hydraulic pump that came off the hoist of a two ton farm truck. Is there a way to tell what the rotation of the pump is? There's no marking on either of the ports. I remember one time someone saying that usually the in port was bigger and if you look in it that the proper rotation is where the gears mess that they will be turning toward you.

Any help is appreciated.

Bob

 

[dfkrug]

A friend gave me a Borg Warner hydraulic pump that came off the hoist of a two ton farm truck. Is there a way to tell what the rotation of the pump is? There's no marking on either of the ports. I remember one time someone saying that usually the in port was bigger and if you look in it that the proper rotation is where the gears mess that they will be turning toward you.

Some pumps are symmetrical and work the same in either direction. If
the 2 ports look different in any way, I would bet it is intended to run only
one direction. IN ports would tend to be bigger than OUT ports, as you
say, but I do not think it would always work that way. The best bet is
going back to the manufacturer and asking, of course.

 

[MJPetersen]

you look in [the in port] that the proper rotation is where the gears mess that they will be turning toward you.

That is correct. The oil moves around the outside of the gears and is dumped as the gears mesh and return for another load. Many people think it is the other way, but that is correct.

Mike

 

[J_J]

There might be a directional arrow on the pump, or just enter the name, and model number in the search block on your computer.

 

[unioncreek]

I took the fittings off so I could see into the ports, you couldn't see any gears. I decided to clean all the crud off of it, I had already cleaned most of it off. Lo and behold someone has used a chisel to mark the rotation on one of the narrow ridges.

Thanks for the help.

Bob

 

[J_J]

I took the fittings off so I could see into the ports, you couldn't see any gears. I decided to clean all the crud off of it, I had already cleaned most of it off. Lo and behold someone has used a chisel to mark the rotation on one of the narrow ridges.

Thanks for the help.

Bob

What are you going to do now that you got it apart? I would at least put new o-rings and what ever comes in the rebuild kit. Look at the inside real good for scratches and scoring, and if you find such, take it to a hydraulic shop for a professional opinion. You need to know the displacement and pressure for the pump so you can use it correctly. Otherwise, will it do the job that you want.

 

[Yankee Clipper]

Union Creek,

The way rotation is determined on a gear pump is from the shaft end. Look at the ports - the larger will be be suction port and the smaller is the discharge port.

Picture fluid coming in the suction port and filling the outside teeth by the housing - which way will the shaft have to turn to move the fluid to the discharge port? That will tell you whether the pump is CW or CCW.

Good luck!