Corey Wayne

I have recently installed a rebuilt original mechanical fuel pump for my '56 Olds, which from everything I've seen the 4317. It's a vacuum pump which is supposed to power the windshield wipers as well. There is an attachment that is supposed to go with it, the air dome, which is almost like a CO2 canister that fits in the side. It somehow regulates the pressure. I'm wondering if it is possible to use this pump without this piece because I've looked everywhere and I can't seem to find it. Also, because I'm not planning on currently using the wipers, I'm wondering if it's okay to just plug the top holes usually used for the wipers. Does anyone have experience with these fuel pumps. I'm new to this and knowledge is sparse.

Ozzie

The air dome is exactly as the name implies. It is a dome filled with air. It acts like a "shock absorber" to smooth the mechanical pulsations of the pump. The intention is to make life a bit easier on the carburetor's inlet valve. It is similar to the air dome on your house's plumbing to reduce water hammer. It was replaced by the pulsator diaphragm in the late 1950s. You can operate without it, but it is better with it. The intent is to remove it from the old pump and add it to the "new" pump. This forum is already loaded with information about it. Just do a search for 4317 and you will have plenty to read about it and other aspects of the pump. You can make a substitute dome from other fittings. It will work just as well, but won't look "original". You can plug the vacuum ports if you like.