355C Posted September 22, 2021 Share Posted September 22, 2021 We are in need of a complete fuel AC Type B Model 855751. Found one on EBAY, looks correct however, numbers don't type up. Here's the link https://www.ebay.com/itm/223935306918 Eric Voigt voigt2106@sbcglobal.net 951-315-1168 Link to comment Share on other sites More sharing options...
hwellens Posted September 22, 2021 Share Posted September 22, 2021 The one on ebay is not complete even if it is correct for one of the Buick 1931 series; missing cam arm. Based on the data below, there may be a couple options depending on your series. Link to comment Share on other sites More sharing options...
Dave39MD Posted September 22, 2021 Share Posted September 22, 2021 The 31 Buick pump did not have a cam arm like I am use to seeing. It is operated by a push rod and the ebay pump looks just like my 31 Buick pump. Dave Link to comment Share on other sites More sharing options...
Dave39MD Posted September 22, 2021 Share Posted September 22, 2021 I posted a picture of a 5751 below. Hwellens may be on to something as the arm is slightly different but is still a push rod arm. Like you the number on the ebay pump does not show up in any of my catalogs. Then and Now should be able to help find a pump, https://www.then-now-auto.com/ . Dave Link to comment Share on other sites More sharing options...
Dave39MD Posted September 22, 2021 Share Posted September 22, 2021 Here is an illustration from the 1942 AC pump catalog and unless I am not seeing it right it looks more like the ebay pump than mine. What do you think? Dave Link to comment Share on other sites More sharing options...
355C Posted September 24, 2021 Author Share Posted September 24, 2021 Thank you to all. Mark Shaw had new pump that he was not going to use and we bought it. Should arrive today Eric 1 Link to comment Share on other sites More sharing options...
1wonton Posted March 2, 2022 Share Posted March 2, 2022 My fuel pump (5751) doesn't seem to deliver enough fuel to the carb. Diaphragm looks ok; can the problem be a worn push rod from the engine? Link to comment Share on other sites More sharing options...
Pete Phillips Posted March 3, 2022 Share Posted March 3, 2022 If your car has sat a lot and not been used for weeks at a time, this new gas we have these days tends to solidify and clogs up the pick-up tube in the gas tank. Take the fuel line loose at the tank and blow back into the tank with an air hose to clear it out, or run a thin strand of wire back and forth into and out of the pickup tube. Link to comment Share on other sites More sharing options...
1wonton Posted March 3, 2022 Share Posted March 3, 2022 Thanks Pete; the line is clear but the pump does not seem to move enough to deliver the gas. Thinner gasket doesn't do the job. I was just wondering if anyone had experience with the old Buick 90 engine fuel pump push rod.ron Link to comment Share on other sites More sharing options...
Mark Shaw Posted March 3, 2022 Share Posted March 3, 2022 (edited) The push rod may be too short. Remove the pump and compare the stroke length of the current rod (measure from the flat on the block) with the maximum stroke of the pump. These measurements should be close to the same. Also, remove any filters between the pump and the fuel tank that may be restricting flow. Gasoline is a low vapor liquid that can easily vaporize due to the intermittent characteristic of the stock diaphragm pump. If your filter is on the suction side of the pump, it may reduce flow as the filter becomes dirty. I always install fuel filters between the pump and the carb. to avoid this eventual problem. Edited March 3, 2022 by Mark Shaw (see edit history) Link to comment Share on other sites More sharing options...
1wonton Posted March 3, 2022 Share Posted March 3, 2022 Thanks Mark, looks like the rod doesn't push the diaphragm lever all the way. I guess the rod is hardened but I'll build it up a little with weld. 1 Link to comment Share on other sites More sharing options...
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