Running hydraulic pumps backwards?

Have you tried to find the pump info online? As long as the pump is filled with hydraulic fluid there should be no problem with it running briefly in reverse.

To be extra safe you might try disconnecting the coupling and turning the pump by hand to determine the correct rotation. If turning by hand is too slow, then perhaps with a cordless drill, the slower it spins the more likely the fluid already in the pump will provide adequate lubrication to prevent any harm.

A quick review of one pump manufacturer indicated that many (not all though) of the gear pumps are designed for bi-directional operation.

Pete C.

clip) Iny idears?? ^^^^^^^^^^^^^ If it is a gear pump it's easy. The gears carry fluid around the outside, and it gets squeezed as the teeth mesh. So the flow is in the direction that the outside of the gears move. Iny mo questions?

Hydraulic pumps have a case drain that will dump leaked oil back to the intake side. If you run the pump backwards and pressure up the side connected to the case drain you can blow out seals or even hydraulically push a shaft sideways in the housing, causing a lot of damage. While you're trying to figure out which way to go, keep the flow unrestricted.

The intake is larger than the output.

Let go a little farther with this. The fluid flow in a pump ALWAYS takes the longest path through the pump from entrance to exit. Hence the oil in a gear pump travels around the outside of the gears, Someone please give me an example of a pump where this is not true.

Gary H. Lucas

I'll bet there IS an arrow, took me an hour to find one once. You won't hurt it with a quick test but don't run it bakwards for long, that would...suck!

Funny you mentioned this. I did go back, figgering indeed there's *gotta* be an arrow some place. Well, I found what were proly the most cryptic arrows in all of Pump-dom--goddamm....

All seems well. All the advice is appreciated, and I inadvertently followed one, causing quite a mess: Running the pump w/ the hoses disconnected--goodgawd... But, if you know which hoses are the supply, and which are the return (obvious in most cases), effluent oil from one or the other should indicate desired rotation--under low pressure, as the poster mentioned.

Balanced rotary vane pump. Oil at one of the inlets only has to travel less than 90 degrees around the pump before it reaches an outlet. But I've never seen one of those that wasn't marked really well with lots and lots of redundancy.

"B.B." wrote: (clip) marked really well with lots and lots of redundancy. ^^^^^^^^^^^^^^^^ That is really, really, really redundant, as well as being repetative.

gear pump travels around the outside of the gears, Someone please give me an example of a pump where this is not true.

How about an internal gear pump? Chrysler oil pump fer example. The oil goes aronud the Inside of the gear. Pete

Pete, I said it takes the longest path. Take a look at the path of fluid flow in the pump you are talking about. I think you'll find it is the longest path.

Gary H. Lucas

I fully understand it is the longest path. I specifically quoted the part where you stated the oil goes around the

-outside- of the gear. You specifically asked for an example where the oild does not go around the outside of the gear.

I fully believed you were challenging someone to find an example where they could not visually determine the pump operation from the outside of the casting, because you supplied the 'obvious' information that the oil will always go around the outside of the gears.

My example shows where it is harder to look at the outside of a casting, and know where the oil passages are located, which is the point this thread was exploring.

Pete

But didn't pertain to the subject at hand.

Tom

Pete, I read what I wrote again. I read it as asking if anyone knew of a pump where the fluid doesn't take the longest path. It wasn't a challenge, it was a question. I've been using this approach to tell the correct rotation of pumps for a long time. I'd like to know if there are pumps where this is not true, so it doesn't bite me in the ass some day.

Gary H. Lucas