Gary,
Sorry for this long post, but hopefully it will be helpful to anyone doing a 40083 pump rebuild.
A note about rebuild kits. The 40083 rebuild kit is different than the 4656, 4657 and probably other bolt together pumps. The base of the 40083 has two ears where the base screws to the bottom pump housing, thus the bottom gasket also has these two ears.
The first picture is what I was referring to. Not sure what it is really called, but the shaft with the rubber diaphragm and 'cups' on each side. The cups and shaft are swaged onto the shaft. With the kit I purchased you need to carefully grind away enough of the swaged material to remove the bottom cup retainer to replace the diaphragm and then reassemble the cup and swage the end of the shaft.
The picture from Ecklers does not look correct to me. For the 40083, the bottom gasket has two ears for the two screws on the bottom. Second picture is of the bottom of the 40083 fuel pump that I rebuilt 10 or so years ago when I was restoring my old 66 L79. This is the original tiger striped lower gasket. When I did that pump, I used a kit that I probably got from Paragon or Corvette Central at the time. As I recall that kit did include a new shaft/diaphragm assembly which I used.
Something else to be aware. The 66 I am currently working on had an aftermarket Carter or Airtex carburetor. We were able to find a 40083 than another friend was willing to sell. He had owned it for at least 10 years and had purchased it as a professionally restored pump.
We installed the 40083 pump and tried to start the car. As soon as we cranked the car, fuel started to pour out of the vent hole in the front float bowl. I then took the pump off and disassembled it. Fortunately, I still had the original 40083 shaft/diaphragm from when I rebuilt the 40083 for my 66. I compared that assembly to the one in the current 40083. I found that the shaft from the pump I was working on was about 3/16" longer than the old shaft/diaphragm assembly. So, I installed the old one and the pump works fine.
I assume the longer shaft must produce more fuel pressure and it was great enough to blow fuel by the needle and seat. My caution is if you do rebuild a 40083 and the kit include a pumping shaft/diaphragm assembly, make sure to measure and compare the length to the original from the pump.
Don
Sorry for this long post, but hopefully it will be helpful to anyone doing a 40083 pump rebuild.
A note about rebuild kits. The 40083 rebuild kit is different than the 4656, 4657 and probably other bolt together pumps. The base of the 40083 has two ears where the base screws to the bottom pump housing, thus the bottom gasket also has these two ears.
The first picture is what I was referring to. Not sure what it is really called, but the shaft with the rubber diaphragm and 'cups' on each side. The cups and shaft are swaged onto the shaft. With the kit I purchased you need to carefully grind away enough of the swaged material to remove the bottom cup retainer to replace the diaphragm and then reassemble the cup and swage the end of the shaft.
The picture from Ecklers does not look correct to me. For the 40083, the bottom gasket has two ears for the two screws on the bottom. Second picture is of the bottom of the 40083 fuel pump that I rebuilt 10 or so years ago when I was restoring my old 66 L79. This is the original tiger striped lower gasket. When I did that pump, I used a kit that I probably got from Paragon or Corvette Central at the time. As I recall that kit did include a new shaft/diaphragm assembly which I used.
Something else to be aware. The 66 I am currently working on had an aftermarket Carter or Airtex carburetor. We were able to find a 40083 than another friend was willing to sell. He had owned it for at least 10 years and had purchased it as a professionally restored pump.
We installed the 40083 pump and tried to start the car. As soon as we cranked the car, fuel started to pour out of the vent hole in the front float bowl. I then took the pump off and disassembled it. Fortunately, I still had the original 40083 shaft/diaphragm from when I rebuilt the 40083 for my 66. I compared that assembly to the one in the current 40083. I found that the shaft from the pump I was working on was about 3/16" longer than the old shaft/diaphragm assembly. So, I installed the old one and the pump works fine.
I assume the longer shaft must produce more fuel pressure and it was great enough to blow fuel by the needle and seat. My caution is if you do rebuild a 40083 and the kit include a pumping shaft/diaphragm assembly, make sure to measure and compare the length to the original from the pump.
Don
Comment