Vacuum booster plumbing

[Ryan_M]

Thank you, Bob W, for saving the night. I switched the lines to match your pic (and opposite my old pump) and it fired right up. As I've stated before: it is a miracle I've made it this far with my jeep project given some of the incredibly minor league obstacles that have brought the progress to a grinding halt.

[garage gnome]

These old fuel pumps are an item with high failure rates. It is extremely unlikely that any running CJ-3A still had the original fuel pump past the 80's. I have never seen any documentation to indicate anything other than part number 647911 being used throughout CJ-3A production. 647911 is an AC series CF fuel and vacuum pump.

My '53 was still using the original pump. I changed it out only because I didn't want the vacuum portion. And then I noticed little pieces of rubber in my fuel filter. So I think the diaphragm was starting to give out.

[calvinhunt]

Here's a photo I took some time ago when I removed the left fender to accommodate some problem I was chasing. �
It shows my dual action fuel pump as well as the routing of my vacuum tubing. �

Sorry to be so late to respond. �I've enjoyed the thread. �

[Rob G]

I�m working on my CJ3A wiper system.� I have found the �modifications� to it interesting at best.� I am going to reinstall the fuel/vacuum boost pump but the plumbing has been modified beyond repair. Is it possible to purchase the tubing for the vacuum boost pump or is it something I will have to manufacture myself.

[athawk11]

Hi Rob,
 I have not seen these 3A vacuum lines reproduced.  They were pretty unique to the 3A, so not a very large replacement market for them.  Also, if the manifold was ever changed on the 3A, the connection point , thus the vacuum line design could vary.  This would make it even more difficult to reproduce on a large scale.

They are not super difficult to make if you have a tube bender and flaring tool.  The vacuum lines are inexpensive and carried in multiple lengths at NAPA and other auto parts stores.  Ask them for 1/4" brake line.   

[Rob G]

Thanks for the input!  After search far and wide on the internet I figured I would have to make them myself.  I�ll check NAPA out this weekend.  I would imagine they will have the bender and flaring tools as well.

Thanks again for the information.

Rob

[BillT]

pertaining to the flaring tool be sure to ask for a tool that makes the double flare and you will need to have a tube cutter also.

[Rob G]

Will do!  Do you know off hand if the vacuum fittings are the same thread as the fuel lines?

[BillT]

I would say that they would be. I have a '65 cj5 engine that had  tubes bent at 90 degrees that you just slipped rubber vacuum hoses onto. Lot'sa different stuff out there.

[Rob G]

Thanks for the information!