I removed a wornout AC Type 4657 fuel pump from my 1960 about 10 years ago and installed an aftermarket (with much difficulty due to inlet/outlet differences). My car is a driver so I am not worried about having a 4657 instead of a 4656. Question, is there any reason not to buy a rebuild kit and do the work myself? Can I purchase the rebuild kit at local auto part stores? Anything to watch out for during the rebuild.
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Re: C1 Fuel Pump
Joe,
The AC pumps are easy to rebuild, but I don't think that you can get a kit at your FLAPS. I usually buy my kits from Paragon, and they are good kits. The hardest part is getting the new diaphram hooked on the lever, but after you have done it a couple of times it is very easy. Just pay attention to the direction that the check valves come out 'cause if you put them in backwards, it won't pump! Don't remove the lever pivot pin unless the lever is very worn. The levers will usually last through several rebuilds and will usually only show wear where the diaphram hooks on the lever.
Regards, john McGraw -
Re: C1 Fuel Pump
The 4656 (late straight axle) and 4657 (mid year) fuel pumps are actually the same with two exceptions: (1) the part ID number embossed on the pump mounting flange, and (2) the orientation of the pump's center body (where are inlet/outlet positioned relative to the upper flange). Since these pumps were intended to be rebuilt and the three body parts screw together, it's a snap to convert a 4656 to a 4657 (and vice versa) by simply rotating the body.
BUT, before you spend the time to rebuild this pump, you might want to check around and see if you can swap it for a correct/original 4656 for your car. The 4657 stamp on the upper flange has more value on a '63-65 Corvette....Comment
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Re: C1 Fuel Pump
I found a page on the Restorer CD that describes how to convert the 4657 to 4656 by rotating the top. Is the Technical Discussion board the appropriate forum to let other members know that I would like to swap? I don't have time to advertise in the Driveline because my engine rebuild will begin in the next few weeks. If there is a more appropriate place to do this, please let me know what you think. I value your opinion.Comment
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Re: C1 Fuel Pump
Joe,
The only problem with converting a 4657 to a 4656 pump, is that there are two styles of 4657 pump bodies used. One is a dead match, but the other is not. On 4656 pumps, the bosses on the upper surface of the pump body that the screws come up through from the bottom are all round in shape, but one of the 4557 body designs has 2 of the bosses which are square in shape. This can be seen from the top side of the engine compartment and will stand out to a knowledgable judge. While it is true that 4657 pumps have value to a C2 owner, I would think that you would have a hard time finding someone to trade you a 4656 pump for the 4657 given the relative scarcity of 4656 pumps. There are a lot of little subtle nuaunces that can be used to determine if a 4656 pump is a converted pump, but a truly skilled craftsman can produce one that is impossible to tell the difference. It also helps to have some NOS rebuild kits with the proper screws and the proper white wavy line pulsator chamber gaskets, but these kits still show up on Ebay every now and then. If you do run across a NOS kit, I would advise very strongly against using the original diaphram unless you never drive your car further than you can walk home. I have tried to use several of these and have found that the have deteriorated so bad in the box that they were not safe to use. A sharp judge would love to see that little tab with the staple in it that holds all the leaves together, but a modern single ply rubber diaphram is way more reliable.
Regards, John McGrawComment
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Re: C1 Fuel Pump
John, thanks as always for sharing good information. I will look to see if I have all round bosses or two square bosses. Since my car is a driver, I am more interested in installing a fuel pump that has the inlet/outlets on the proper side. The aftermarket pump I have on the car now required a short piece of rubber fuel hose with 45 degree elbows and as I recall, very tough to make all the angles correct so the fuel lines would screw in properly. I will order a rebuild kit from Paragon and have the Type 4657 ready to bolt on when my engine is rebuilt next month. Would it be unwise to reuse the two springs or the two one-way valves? The valve diaphragms still have "spring" to them when I pushed on them through the cover plate holes.Comment
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Re: C1 Fuel Pump
Basically, valves and springs last a long time.... It was the main pump diaphram (originally nylon impregnated cloth) that wore out. Like John says, even if you can find a correct/original diaphram, you'd be foolish to 'bet' on it. PLUS, if you DO attempt to install a cloth vs. rubber diaphram, you really need to study the service manual where it describes fuel pump overhaul.
There's a 'trick' to installing the main body to the upper pump housing to prevent over clamping the diaphram and RIPPING it when the pump first fires. Essentially, you start 3-4 of the housing screws, compress the diaphram via the pump lever, THEN fully torque the screws to 'set' the diaphram in it's fully up position. Now, install the remaining screws. With today's rubber diaphrams, this precaution isn't all that essential.
On using this forum to 'attract' others; well you're reaching a minority of NCRS here (maybe 5-10% of the club) and the rules of the road are NOT to use this as a swap meet facility.... But, your current thread already has a dangle of 'contact me off-line' to it!Comment
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Re: C1 Fuel Pump
Thanks Jack, I decided to rebuild the 4657 and keep it. I ordered a rebuild kit from Paragon. Sounds like I could probably reuse the original valves and springs, but since I paid for new ones, I will use them. Do the valves just pop out if I tap on them with a center punch? It looks like the "hardest" part of the rebuild will be reinstalling the "connecting arm" to the diaphragm rod.Comment
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