Vacuum pump

Mjfire1949 · Post by **Mjfire1949** » Fri Jul 18, 2014 7:48 pm

The '52 M38, SN-65666, that I bought has the original dual fuel/vacuum pump. I have sent it off to be rebuilt. The guy I bought it from didn't have any of the vacuum lines hooked into it. When I put it back on, is it ok to block all of the vacuum inlets and outlets with plugs? I plan to plumb it eventually, but I have other priorities first. (Oil leaks) I don't want to leave these open unless I have too. I know the vent inlet on the carburator needs to be open. I want to make sure none of the inlets/outlets on the vacuum pump need to be left open. Thanks in advance.

Post by **wesk** » Fri Jul 18, 2014 8:54 pm

If you are running the original military 24 volt distributor you need to go ahead and install the three short pieces of tubing to keep the ionized gases in the distributor from reaching an explosive level and to keep the coil cool during the summer.

1-Line from pump outlet to the intake manifold.
2-Line from pump inlet to the wiper "T".
3-Line from wiper "T" to distributor.

It would be a good idea to plumb the other port on the distributor to the induction crossover where it belongs as well.

You can find all the pieces at your local hardware &/or auto parts store. Should cost about $20 and two hours hobbyist labor. You can use copper coated steel tube and fabricate your own, or just buy the ready made brake lines in the closest length. Or you can use the easier to work with copper line.

At any rate I would not plug the two ports on the pump. That would place undue stress on the diaphragm.

Mjfire1949 · Post by **Mjfire1949** » Fri Jul 18, 2014 10:31 pm

Thanks Wes. I made a pretty good deal on this M38, but I'm starting to realize there's still a lot to be done. It does have the 24 volt distributor. I need to replace the rear main seal, and then I'll tackle the vacuum lines. The engine has a miss in it that I suspect may be resolved when I get these lines plumbed. Have a good weekend.