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Working on my 32 DL and I'm attempting to rebuild my B and B Model 517S updraft carb and have run into a problem right from the get go. I have the three screws that hold the top casting to the lower casting. But when I try to separate them, the accelerator pump hangs up and won't come free. The brass piston is free and will move in the bore, but whatever is attached to the rod that passes through the brass piston and down into the bore seems fixed solid. I don't want to damage anything trying to force it out, In the picture below you can see the two castings separated, the brass piston and the rod that passes down into the bore. The rod will move down, but at a certain point it will not move up.


Is there something attached to the rod that needs to be released? This is my first attempt at an updraft with a mechanical accelerator pump, so please excuse my ignorance.

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Thank you keiser31 and carbking - the pin is out and the castings are separated. Jon, I'll call you Monday, thanks for the offer. You rebuilt a carb for my 29 Plymouth back in the seventies and it's still going strong.


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Well, the saga continues. With a bit of patience and some penetrating oil, I got the plunger in the accelerator out. The bore was full of rust and varnish and that was holding it in.



Once that was out, I removed the float and went to work on the three items pictured below - I'm using these charts to ID parts...



So I guess these three are the Step-up Valve Assembly, the Pump Valve Assembly and the Check Valve Assembly. Naturally, I ran into another problem. As you can see, the assembly to the right (Check Valve?) already had some damage to the top. As it always seems to go, the first two assemblies came out with no problem - just a bit of effort with a large screwdriver and they broke free. Ahhh...but why is it always the last one that's such a bugger? It stuck fast, and all I did, despite using a wide blade screwdriver and trying to be careful, was to tear up the top even more.


So, what's next? This stuff seems delicate, so I don't think blasting a lot of heat in there is a good idea. I might be able to get a pair of vise-grips on it, but that's really going to tear up the part and I'm not sure if a new one of these is readily available down at the local NAPA. As always, suggestions are always welcome. I don't want to tear the poor thing up any more that I already have!

Once I solve this, I'm sure the next catastrophe is right around the corner.

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So, seems to me the best thing is to send the carb to Carb King. Knows what he is doing; a friend of the hobby. Why mess around when there are experts out there. You cannot take it with you!


Carbking no longer rebuilds, he now manufactures and sells quality rebuilding kits. I will take him up on his offer and call him Monday afternoon to see if there is a solution to this problem.

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Jon's advice on removing the Step -up Valve may prevent future carb rebuilders from making the mistake I did. Someone had already torn up the top of the valve and my attempts to turn it with a large blade screwdriver really messed the top of the valve up.

Here is the valve before I really tore it up.


It simply wouldn't come out, so my advice is - if you get to this part and it won't turn, do not force it. Following Jon's advice, I put the lower casting in the oven at 500 degrees for about half an hour. Then I removed it and played a MAP torch over the bottom of the casting in the area where the valve was located for a few minutes and then let the casting cool down naturally until it reached room temperature. Do not quench the casting.. Jon told me that I would need patience, and he was right. The first attempt did nothing and the valve still would not turn. So, I went through the process again. This time the valve turned easily. It might even take three tries on some castings, but it will work. Patience -something I have very little of.

Unfortunately, in my case, I buggered up the valve pretty badly. Aside from tearing up the top, my attempt at turning the valve with a pair of needle-nose vice grips scarred the sides of the valve pretty badly.



The valve comes apart with the bottom cap screwing off the valve to expose the spring and a tiny ball bearing which is not in the photos because it kept rolling away. Jon says the spring will be damaged by the heat, so don't reuse it. So, I'm calling Jon tomorrow to order a complete rebuild kit and the top half of the valve - which is going to set me back in the range of $115. So don't make the mistake I did - go gently and use the heating method, not brute force, and save yourself a bundle.

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This is the link for All American Carburetor. http://www.allamericancarburetor.com

i have been aircraft mechanic for over 40 year and have rebuilt pressurized Carburator and fuel controls,

rebuilt plenty of rochestor and carter for cars,

when it comes to the vintage Carburator the throttle shaft usually have play in them and they will not idle correct because of vacumn leaks,

these see guys are quick turn around , usually in 2 weeks, and they don't rebuild , they remanufactuer back to mfg specification.

They did dual carburetors for my 35 and match the jets,

great work ,


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I'm having to give up on the carb. Heating up the casting worked but also revealed several rust holes in the bottom of the float bowl once i cleaned everything up. Another hole had opened up in the side of the float bowl. Also, two of the threaded holes in the top casting had been repaired with Heli-coils sometime in the past before Phil and I owned the car and they stripped right out when I removed the screws. I also discovered that this is the wrong carb for the car, it's actual application is for a early forties Chevy or GMC C.E.O. truck. It always worked fine back in the sixties when I was driving her, but it is incorrect for the car. Now it will just serve as a parts source.

I have located the correct carb for the car and bought it. Since I needed to buy close to two hundred dollars in parts to try and fix the old one, I guess the three hundred buck price tag was acceptable. Pardon me while I cry myself to sleep.

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Sometimes this happens.

Many of the parts will interchange:

Pump piston, "top hat", both check valves.

Power piston plug


Possibly interchange

Power jet pushrod, high speed bleed, both idle tubes, choke and throttle valves


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I have a BB1 that is filled with dirt. It's yours for $25 that includes priority shipping. The car it came from was swept up in a flash flood so that's why it's filled with dirt. If you want pics let me know.

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