'39 Special Double action pump

[Guest Faust]

I recently "recovered" a double action pump from the trunk of an abandonded "project" '39 Special. I am told that this is unique to the '39 Special. Is that the case? Is there a number I should look for?

I have inserted a "thumbnail", click it to enlarge. It had been repainted and there is still masking tape on the actuating lever. The thuimbnail leads to an unusually large pic, so I have also attached one.

[Guest sixpack2639]

Faust, look around the flange where the pump mounts to the engine and there should be a number stampped into the flange. Carl

[critterpainter]

Looks like a late 40's fuel pump. With the tape on the lever I can 't confirm small or large series but I think small. Flange # would help, but not absolute last word as people have been known to change actuating arms.

Bill

[Glassesguy]

Cannot confirm the 39 double pump # for Series 40 --yet. Standard (non-vacuum)pump looked like a regular pump but turned upside down so the glass bowl was on top. Late production 38 Series 40 was that way also. 1938 Series 40 had a double pump available #1523687 as shown in BPS 2.017 It had the same bottom as yours but used a fuel pump section that more resembled that of the 1940 and later versus the one on yours. As the guys have mentioned AC interchanged bodies, and arms depending on their application. Repair shops did it too probably depending on what it took to get the car back on the road especially during the war when parts were harder to get. Check the flange that bolts to the engine for a number. Original number is 7 digits (or sometimes 4 ) but rebuild companies often filed these off and stamped their own 3 or 4 digit number. Take the tape off and let's see that arm assembly. Great picture by the way.

[Guest Faust]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Cannot confirm the 39 double pump # for Series 40 --yet. Standard (non-vacuum)pump looked like a regular pump but turned upside down so the glass bowl was on top. Late production 38 Series 40 was that way also. 1938 Series 40 had a double pump available #1523687 as shown in BPS 2.017 It had the same bottom as yours but used a fuel pump section that more resembled that of the 1940 and later versus the one on yours. As the guys have mentioned AC interchanged bodies, and arms depending on their application. Repair shops did it too probably depending on what it took to get the car back on the road especially during the war when parts were harder to get. Check the flange that bolts to the engine for a number. Original number is 7 digits (or sometimes 4 ) but rebuild companies often filed these off and stamped their own 3 or 4 digit number. Take the tape off and let's see that arm assembly. Great picture by the way. </div></div>

I have scraped the paint off and can only find 3 digits. It appears to be 529. The 9 is a guess. It appears to be doubleor triple stamped, and loks more like an ampersand. I am attaching a picture of the lever. It is about 1 7/8 long and 5/8ths wide. Other than that, all I can find on it are several raided "Made in USA' and a circled "A". These are raised markings and visible through the paint. The stamped numbers were not.

[Guest Faust]

Sorry about the attachment, I will have to learn how to reduce my pictures. The arm is obviously rusted and the contact portion seems to be machined. Although that could be wear from use.

Maybe this is better:

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[Glassesguy]

Faust:

I'll bet that 529 is an Airtex or AC rebuild #. Maybe somebody on the Forum has an Airtex book. I'll check as well. That arm appears to be for the small series and is definitely used but good. Thanks for the great picture and digging for that # on the flange.

[Glassesguy]

Faust:

Sorry for the delay in replying. Been off line for a few days. The 529 number corresponds to part # 1523529 listed as a combination pump for 1940 Ser. 40 & 50 after eng. # 44034048 on Ser 40 and #54034048 on Ser. 50as well as all 1941 thru 1951 Ser. 40 and 50. Admittedly the vacuum section (on top) looks different from the ones I have seen in Buick literature, but who knows what may have been done over the years. The actual # for the 39 pump is the same as the optional pump for the 38 Ser. 40 according to the 28-41 Master parts book. The 36 thru 58 parts book lists AC kit # R-30 as the combo pump repair kit for 1939 Ser. optional pump and all 1940 thru 1951. AC # D-28 is the vacuum pump repair kit while AC # D-18 is the fuel pump repair kit for these years as well. AC calls this a Series AJ pump so while the exteriors may look slightly different, the innards are the same. Interestingly enough, AC stated no exchange pump was avialable for the 38-39 optional pump. Looks like these owners had to have their pump rebuilt vs exchanging for a rebuilt one. That's when it's good to know what other series AC pumps use the same components. I believe the difference between the 39 and 40 early pumps vs that of the later pumps was the size of the mounting holes and bolts holding the pump to the block. Someone possibly could confirm this. Hope this helps.