On my 1951 Chevy Deluxe Coupe, my mechanical vacuum/fuel pump is spitting fuel out the side. I replaced this about 8 years ago, but have only driven it a couple hundred miles in the meantime. Was thinking of replacing with a 6-volt electric fuel pump to avoid having the problem again. Is this just the normal life span of a mechanical pump? Any thoughts, recommendations are appreciated. Thanks.

Your fuel pump needs to be replaced. 8 years is a long time for a old pump to last. Replace it with either a new replacement fuel pump or if the old one is rebuildable either get the parts (NOT NEW OLD STOCK) but you need the new material diaphram that will resist the destruction that our presently available gasoline does to NOS materials. I posted a telephone number of Terrill Machine company that specializes in rebuilding vintage fuel pumps. Also The Filling Station should have a replacement fuel pump and a rebuilding kit for your car. Both of these vendors advertise in the VCCA magazine. A 6 volt electrical pump will be just an expensive short term fix that will cause you more pain than gain, in my opinion.

Hope you don't mind me posting a little story here.
Back around 1970 I drove my '64 Pontiac Parisienne 4dr.htp.to Florida.283 2bbl.dual exhausts.On the way home it seemed to be using lots of gas and I opened the hood one time with the engine running and gas was spraying out a vent? hole on top of the pump.
I was near Chatanooga Tenn. and left it at a garage to have them replace the pump. When I returned,paid the bill and went to crank it, there was a large bang. I looked at the pump and it wasn't sitting against the block.They put a Pontiac pump on it, not realizing that Canadian Pontiacs have Chev engines. But they never even ran it after replacing it. I borrowed their tools, a guy gave me a ride to a dealership in a '55 Chevy.The rod that operates the pump lever was all bent out of shape.I was lucky that nothing else broke. I installed it and drove home fine. A friend of mine wasn't so lucky. Same problem and his burned on the way for repair.
Anyway, I do have a question. After what point were fuel pumps okay with modern gas? 1960-70-80-90 ?? Just curious.
Neil

i have never replaced a fuel pump in any of my "old" cars in the last 30+ years due to gas damaging a fuel pump diaphragm. And I have used gas from at least 25 different states.

Replacing a fuel pump diaphragm out here is very common. As a TA I get calls on the problem all the time. Just got a call today as a matter of fact from a VCCA member in Southern California that had a defective fuel pump diaphragm. It lasted about a year and that was it. The gasoline in California ate it to pieces.

Last month got a call from a fellow back east....same thing, so it does happen and it seems to happen fairly often.

I have run tests on the new diaphragms by submerging them in gasoline for long periods. The last one that I tested turned to jelly within six months. Keep in mind that all of the above were new diaphragms that were supposedly impervious to the modern gasoline.