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What outer-diameter size of vacuum lines were used on the d-a fuel pump (47-55)?

I have two sets from used pumps that were installed by owners. They are had 1/4" outer diameter lines. Brass adapters are in the threaded pump-ports (the tube ends are compression/ferrule fittings).

Thanks,

Hi Tim,

Denny has some photos of the plumbing for a d-a fuel pump in his 1950 album. Would these help?
http://www.pbase.com/dennygraham/image/137141442

Peter,

Yes, I have seen those. Thanks. I miss Denny. I hope he is getting settled in his new house, yard, and shop.

It looks like they are smaller than the 5/16 fuel line. My guess is that they are not 3/16, but that is my quandary: 3/16 or 1/4. I might send Denny a PM or email.

Tim,

I agree with your analysis both of the vacuum line and Denny. The two of you are some of the best go to guys we have.

Mine has 1/4" tubing on my 37 Buick with a DA pump and the same on a customers 40 Pontiac. One is a straight 8 and the other a flathead 6 so it seems GM used the 1/4 for all. This may or may not be of help.

Tim,
my impression is that they were dealer installed, not factory installed. Is that correct?

Fred

Fred -

Don't mean to jump in front of Tim's answer to your question --

The Fuel & Vacuum Pump was factory installed. 1954 RPO #340, $8.50 list price. Factory Assembly Manual instructions Section 0, Sheet 18.00

Of course it could be installed by the dealer, too.

'29-'54 MPC: "52-54 ALL (2nd design) .... fuel and vacuum, dbl. action (AC-9797 .... 5592675 .... $14.65"

The second design had in-out ports for fuel line that were angled 20deg to the block in order to clear the side mounted motor mounts that were used on passenger cars starting in 1952.

I searched through the MPC and FAM, but couldn't find reference to the size of the lines.

Jump in front any time, Lonnie.

Thanks, everyone, for the posts.

I'll go with 1/4", since I already have those fittings. I'll be using copper-nickel tubing from Advance-Auto (best price).

Bigger is always better on vacuum lines- - - -that's why the big trucks with the Hydrovac used 1/2" hoses from the manifold to the reservoir tank. If you've got an option when installing a new system, use 5/16" hoses and hard lines, and hide a small reserve tank with a one-way check valve somewhere out of sight. It might not be OEM, but it will make the wipers and other vacuum-operated accessories work much better. The softball-sized round plastic vacuum reservoirs from a newer car will mount somewhere out of sight down in a fender well, etc. and won't detract from the antique appearance.
Jerry

I have the dual action pump from Chev's of the 40s. It takes 1/4" MNPT.

Per Jerry's suggestion, I'm mounting a vacuum reservoir tank under the cab and using a brass 1/4" MNPT fitting to a flared 1/4" ID copper line. I'm using an Erson tank which is a bit bigger than a softball but I recently found these 1980-82 Corvette headlamp tanks. They look like tin cans so they blend in with the antique look a bit better.

Mine looks like this...
Erson vacuum reserviour tank

Mine will get tucked up in a frame rail or hidden somewhere. ...the difference is, I got it for $20 with a gauge and all the fittings where as the Vette tank is +/-$60 depending on where you find it.
That said, I might get the vette tank just for the look and sell mine.

BLUEMEANIE,

Where did you purchase your reservoir? Summit has it or $45

ebay. Summit sells the exact same one. Erson, Summit, Jegs, Crane, etc. same tank.
In fact, if you search "vacuum tank reservoir" the first auction to come up is under $3 with four days left for the same tank plus a new Autometer gauge.

Those tin can tanks were original equipment on a lot of 60's and 70's GM vehicles, so a salvage yard search might turn one up on vehicles of those vintages. I think a wrecking yard would just about give one away.
Jerry