Help Identifying function in hydraulic pump

[JustIH]

When I opened up my hydraulic pump I found a bearing but no spring. This is a pump off a 444 gas tractor. In the picture there is a hole in which the bearing fits. Is this for the overflow on the gear mesh to keep pressure from building up in side the pump.Someone with some knowledge of this your input would be apreciated. Someone had opened up this pump in the past found silicon inside. The pump did work but leaked.

 

[used red MN]

Just taking a wild guess that it may be there to bleed
air. So when just a bit of of fluid is in there and some
air the ball in the horizontal hole drops off the seat and
allows air to pass. Once pressure and flow builds up oil
going past the ball pushes on it enough to seat it. Just
FYI oil is not pumped by squeezing between the
meshing gears. The oil is pumped by being captured
between the teeth and carried around the ends of the
figure 8. The meshing gears seal to force the oil out
the outlet.

 

[wore out]

The lightly spring-loaded check ball relieves any oil pressure buildup next to the seal by opening and allowing it to flow into the suction side of the pump when the pressure there is less than in the seal area.

Spring 371523R1 is still available from CIH for $2.23.

 

[JustIH]

Just wanted to thank you guys wore out and used Red MN . You confirmed
what I was thinking. But it was nice to hear from someone who knows what
they are talking about.