Jump to content

1940 6 cylinder fuel pump spitting oil

Recommended Posts



I have the vacuum pump fuel pump combo and I've replaced the diaphragm and seals on it with a kit from bopparts.com. so I know the seals are new. I'm having a problem though that the oil gets past the gas side oil shaft seal and them it leaks out the two small breathing holes (I think). Has anybody seen this before? Not sure how to keep the oil out of the diaphragm chamber. 

Link to comment
Share on other sites

@mtl92 I've had quite the time with my old Carter fuel pump. It came off of my 1952 Pontiac Chieftain straight-8, when I first bought the car there was a significant hole in the diaphragm yet it still somehow ran even though it couldn't have been making vacuum and was filled with oil..


You may have to take it apart a few times, did you install your oil seals correctly? There should be two thicker round O-shaped seals with a bit of a lip in them, they need to go a specific way and then they are hammered in with a steel ring. If they aren't set properly it's very possible these are leaking. Send me some pictures of what you have so I can see where it's leaking and what pump you have. Is the pump at least pulling & feeding as it should? If so, you've done a good job so far. These things are very tedious!











Edited by MercMontMars (see edit history)
  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...