rebuilt fuel pump has no pressure

southpw · Post by **southpw** » Thu Aug 06, 2015 2:32 pm

I have a AC4260 dual action pump and bought a rebuild kit from Then and Now. I hook up a vacuum tester to the vacuum side and get about 4psi while pumping and then gradually drops to zero after I stop pumping. Takes about 5 seconds to drop.
Hook up vacuum tester on fuel side and get no action on the gauge at all. Tried both ports and nothing. Any ideas why?
could the hand lever cause a loss of vacuum because it doesn't have a seal where the shaft enters the body of pump?
The stem of diaphragm is sitting on the two arms that are attached to pump lever. Should they just sit on top of these 2 arms or somehow clip into/onto them some how? The exploded view of the pump doesn't really explain how this should be attached.
Brad

southpw · Post by **southpw** » Thu Aug 06, 2015 4:02 pm

Correction.... vacuum side of pump sits on X and Q (Link on pg 60 of ORD 9 SNL G-740)
The fuel side diaphragm clips onto W (Link). But when I remove K (body) and pump the arm iI see the diaphragm is not moving at all. The center link (W) doesn't move during the pump action and the hand primer lever doesn'tdo aanything either.
I am totally baffled. It was difficult to see how it was all hooked up prior to disassembling but documented as much as I could with pictures but hard to get pictures of the inside during disassembly.

southpw · Post by **southpw** » Thu Aug 06, 2015 5:08 pm

Well ORD 9 - 1828A States dual pumps can not be bench tested on page 120 section f. So this could be the reason.
But after reading this book, it states to soak diaphragm in kerosene but the instructions from Then and Now said nothing about that. What are your thoughts? Needed or not?

RICKG · Post by **RICKG** » Fri Aug 07, 2015 7:14 am

The guys at then and now are easy to talk to and willing to help. I'd call 'em..