View Full Version : Fuel Pump dual action to single action on 57 CJ5

05-17-2017, 07:35 AM
Hi, First time poster here, recently purchased 1957 CJ5, dealing with fuel issues. I would like to change from the dual action fuel pump to the single action pump. My jeep uses electric wipers anyway. I am wondering if this is OK to do. What do I do with the vacuum line going from the crankcase vent up to the intake manifold via the fuel pump? Do I just change the plumbing to bypass the fuel pump? Or is there more to this? Thanks, Tom from Mass.

05-17-2017, 08:18 AM
Since the CJ uses electric wipers, the vacuum section of the pump is not needed.

I suspect you have a F-134 in the '57 CJ. The line from the crankcase vent was to assist in oil control - it kept the crankcase at a moderate vacuum to reduce vapor blow-by from worn rings. In the older L and F heads, there was a hose from the oil filler tube to the air cleaner or induction tube. On the L-head there was also a "PCV" valve - but air pollution wasn't the issue back then.

I suspect just routing it to the intake manifold would do the job nicely.

05-17-2017, 12:36 PM
Thanks LarrBeard. That is what I was thinking. The fuel pump line just "T"s off the line going from the Crankcase vent up to the intake manifold. Tom

04-16-2018, 11:06 AM
Did you figure out this swap from dual action to single action pump? I am wanting to do the same on mine.