New front hydraulic pump on my NAA. Do I need a relief valve?

pknapp · Jan 15, 2017

Hi,

I just installed a new higher flow hydraulic pump on my NAA and the tractor stalls when reaching the end of ram travel. The original pump
was mounted on the Wagner loader frame and matches the one in the wagner manual. There is a brass nut on the back of the old pump
which looks like it might be a bypass valve. The new pump does not appear to have a bypass valve. It is sold as a replacement for the
original pump by many sources. I attached a picture of the new and old pumps. Do I need a relief valve with the new pump? I went with
The new pump to speed up my log splitter which it does well. New pump is in the first picture.

KWentling · Jan 15, 2017

Always need a pressure relief. Your valve may have one built into it. If it doesn't, you need to add one, I'd adjust so it relieves before it kills the tractor. Please don't use pipe fittings on the pressure side. They are not rated for the pressures seen in hydraulic circuits.

pknapp · Jan 16, 2017

KWentling said:
Always need a pressure relief. Your valve may have one built into it. If it doesn't, you need to add one, I'd adjust so it relieves before it kills the tractor. Please don't use pipe fittings on the pressure side. They are not rated for the pressures seen in hydraulic circuits.

Made some headway tonight. Found that after a short time when the fluid warms a bit the loader does not stall the engine. I found my log splitter valve online and found where the relief was hidden under a small plug. I backed off the relief adjustment a turn and a quarter and the tractor no longer stalled but the splitter still has a ton of power. Either the old pump was really weak or it has a bypass built in since the tractor never stalled with that pump.

I am not using the pipe fittings that came with the pump on the pressure side. Everything is steel or hydraulic hoses. Thanks for your concern. This can be easily overlooked.

LD1 · Jan 20, 2017

So what pressure are you now supplying to the splitter?

Nothing is free. More flow at the same pressure requires more power. You didnt have more power so had to sacrifice some pressure. Its a trade off. How many GPM is the new pump supposed to be? and what was the old one?

Dave M7040 · Jan 28, 2017

It is best to not work on any hydraulic system without an inexpensive pressure gauge.
$30 at a local hydraulic shop will get you a gauge and a quick connect fitting so you can plug it into your system and see what is happening.
Making adjustments without a gauge can lead to very expensive things breaking.

The splitter valve would have its own relief.

Where is the hydraulic oil for the engine front pump getting filtered? Filtering is key to long life.

Dave M7040