1970 Fuel Pump?

[Kevin Bielinski #13320]

The fuel pump went out on my '70 Coupe DeVille. Every pump I've picked up has a larger output fitting than my stock fuel line. Anyone else have this problem? Can anyone recommend a specific brand that will attach directly to my metal stock fuel line without an adapter? Last one I picked up was from NAPA. He tried selling me an adapter when I returned it

[fishnjim]

The options for older mechanical pumps is getting smaller, only one or two makers now and often they'll use a different pump(superceded) or it's a reman where they use what parts they have on hand. 
I don't see any issue with an one size adapter.
eg:
I bought a rebuilt generator and I took it back because the hole for the bolt was too small.   They told me just to drill it out which is an easy thing to do.  But I changed the end plate.  So if you want one with the right connection, you might be better off, rebuilding your pump, if it's the kind that can be rebuilt, ie. not the "crimped" style.  Or take that part of the housing off and use it.

[TJ Hopland]

This has come up several times recently and I think the upshot is that there are pretty much no more pumps with the 5/16 outlet fitting around anymore.  Earlier this summer I think someone found a fairly low profile adapter fitting that apparently worked fine.

Pretty sure it was a Tanks Inc BF56.   Available direct from Tanks Inc as well as the usual places like Summit.

[Big Fins]

Simply swap out the piece that the line threads into from the old pump to the new. Make sure you use the new washer too. If your fuel filter is incorporated into this fitting, you will be ahead of the game to be able to change the filter out easily.

[TJ Hopland]

Depending on the age of the parts involved swapping that whole big nut fitting may or may not work.  It appears that different manufactures used different threads.  Start out with a visual comparison and don't force it when you try and screw it in. 

[Kevin Bielinski #13320]

This has come up several times recently and I think the upshot is that there are pretty much no more pumps with the 5/16 outlet fitting around anymore.  Earlier this summer I think someone found a fairly low profile adapter fitting that apparently worked fine.

Pretty sure it was a Tanks Inc BF56.   Available direct from Tanks Inc as well as the usual places like Summit.

Do I have to reflare the gas line to install this?

[TJ Hopland]

No re flare required.  That adapter should be flare to flare and the proper gender.  There must be enough flex in the line to make up for the extra height.  The post where I read about it they didn't mention having to modify anything.

If you have flaring tools in theory you could buy a special fitting that has the 3/8 threads but uses a 5/16 line.  They do that all the time with smaller brake lines so I assume its also possible with larger lines.  If you cut it as close to the existing flare as possible you may not loose too much length but then it would be a pain if you ever did find the original 5/16 pump.         

[klinebau]

The big nut with the 5/16 fitting from your old pump will definitely fit on the new pump.  I don't think the holder for the fuel filter will fit but I am not positive.  If you have an old pump where you can swap out the big nut, then that is the easiest solution and will require no further modifications.

[CaddySteve]

i have an extra 1970 NOS fuel pump

NOS AC Fuel Pump # 40695 GM # 6470007 Cadillac V8 472 500 1969-72

[Kevin Bielinski #13320]

I have 2 more on the way. One supplier in NM said it's the correct one. In the meantime, SoCal Speed Shop has the reducer required. It drops the line by about 1/2 an inch. Picked it up today for 10 bucks. We'll see how these 2 turn out.

[Cape Cod Fleetwood]

i have an extra 1970 NOS fuel pump

NOS AC Fuel Pump # 40695 GM # 6470007 Cadillac V8 472 500 1969-72

Wrong numbers
1970 Fuel pump
w/AC Cadillac GM P/N 6417494
NOS + AC pump P/N 40687
This pump DOES take the fuel filter

[TJ Hopland]

When did the fuel outlet change to 3/8?  I though it was 71?  Was it 73?

Was 68 the only year with the 'regular size' fuel pump?  And those had an inline filter?  This was basically same as 67 but a different pump because of the different engine?  The inline filter was what took over from the 50's which had the glass bowl?

And by regular size I mean like your typical fuel pump everyone was using in the 70's vs the large canister with and without the internal filter that Cad used through the 70's. 

[Kevin Bielinski #13320]

Got two more and the same thing. Decided to keep the one from cad500parts.com and return the Carquest pump. Tried 5 different pumps and all the same. Going to use that reducer. This makes me scared for the future. I know it's already happened but I'm worried about it getting worse. Just hope it comes out without any leaks.

[klinebau]

I have never seen a new pump with 5/16 output.  If I knew then what I know now, I would go all 3/8 from pump to carburetor and be done with it.  Everything in 3/8 is readily available: fuel pump, fuel line, carburetor inlet nut.

[Kevin Bielinski #13320]

Finished the job today. Had to get a 3/8 fuel line and a 3/8 inlet for the carb. No leaks, no adapters and no problems. Glad its finished.