40’ Buick Special fuel pump vent hole

[Bill White]

Hello All,                                                                       A couple of weeks ago I posted a question about 39’, 40’, and 41 Buick Special and Super fuel pumps.  I thank everyone for their responses and views.  I’m including a picture of my fuel pump to see if it is unique to 1940 Specials or Supers. I would appreciate if someone with a 39 or 41 Special or Super could check theirs to see if it looks like mine. I know there is a difference in the arms that ride on the cams from the mod. 40’s and 50’s and the larger models/engines. I was in a bone yard last week and noticed on some of his late 1940 fuel pumps, that there was some sort of mesh in the fuel pump vent hole. I was wondering if anyone has put copper mesh, or something in the vent hole of their fuel pump to slow down the oil leakage that many of us are experiencing. I replaced the felt seal in the vacuum chamber of the fuel pump already, but it still leaks. The old felt seal looked perfectly fine. When doing so, I also found a metal clip like wire that is in the vent hole. I’m guessing to hold in the mesh. I’ve been looking on the internet/EBay to find another fuel pump and called Dave T, but haven’t any luck finding another pump. I’ve also cleaned all the engine vents hoping to make the crankcase breath better to reduce crankcase pressure, thinking that might help. All advice will be happily appreciated.  Thanks, Bill

[neil morse]

Hi Bill:

 

Here's a photo of the pump on my '41 Super -- it looks the same as yours.  I can't get access to explore what, if anything, is in the vent, and I can't remember what was in there when I replaced the pump about six years ago.  I'm not experiencing any oil leaks that I'm aware of.

 

[Bill White]

Thanks to GlassesGuy for the info he provided me in my earlier post. Now knowing that the difference between the 40’ special/Super fuel pump AC 519, and a 41’ Special/Super fuel pump 529 is slightly larger holes in the later where it attaches to the cylinder block, I decided to buy a 529, that I found on eBay. I plan to place tube type spacers (tubes) in the holes to keep the pump centered on the attachment point on the block. Thanks Neil, for posting your photo. I’m feeling better about getting the pump on eBay.  

[1939_Buick]

Not 100% sure but later (compound) pumps also include a vacuum pumps. Earler pumps were fuel only

A little off topic

https://www.teambuick.com/reference/fuel_vacuum_pump.php

 

[37_Roadmaster_C]

@1939_Buick, My 37 Roadmaster 320 has a compound pump.

[kgreen]

The vent opens to the interior of the pump where the actuating arms are connected to the diaphram(s) which is also open to the crankcase.  The filter fabric is an inorganic material, not copper, but not ferrous either.  Stainless steel wool would function fine.

[Bill White]

Good to know. Stainless steel it is.  Many thanks!

[Andrew_Latvia]

On 6/27/2024 at 5:44 PM, Bill White said:

Hello All,                                                                       A couple of weeks ago I posted a question about 39’, 40’, and 41 Buick Special and Super fuel pumps.  I thank everyone for their responses and views.  I’m including a picture of my fuel pump to see if it is unique to 1940 Specials or Supers. I would appreciate if someone with a 39 or 41 Special or Super could check theirs to see if it looks like mine. I know there is a difference in the arms that ride on the cams from the mod. 40’s and 50’s and the larger models/engines. I was in a bone yard last week and noticed on some of his late 1940 fuel pumps, that there was some sort of mesh in the fuel pump vent hole. I was wondering if anyone has put copper mesh, or something in the vent hole of their fuel pump to slow down the oil leakage that many of us are experiencing. I replaced the felt seal in the vacuum chamber of the fuel pump already, but it still leaks. The old felt seal looked perfectly fine. When doing so, I also found a metal clip like wire that is in the vent hole. I’m guessing to hold in the mesh. I’ve been looking on the internet/EBay to find another fuel pump and called Dave T, but haven’t any luck finding another pump. I’ve also cleaned all the engine vents hoping to make the crankcase breath better to reduce crankcase pressure, thinking that might help. All advice will be happily appreciated.  Thanks, Bill

I don't know - maybe it is not a good idea relative to Buick fuel pump, but on a similar fuel pump with problem of oil leaking through actuating arm shaft holes, I'd made a custom fuel pump mounting gasket with center opening just big enough for the arm to pass through. It helped and I don't think there's a need for that much engine oil for lubrication as it gets into the interior of the pump with original gasket.

[Bill White]

I was told that earlier fuel/vacuum pumps, possibly 39’ or a little earlier had something similar to what your talking about. Maybe someone else modified the gasket too,  and the next owner found it and thought it might be original factory.  The pump I just bought on EBay has been rebuilt, but the seller said he had no idea when. It belonged to his grandfather.  I have new diaphragms, so I’m thinking of changing them out. I try not to use ethanol gasoline, but there might be a time when I have no choice.