GTA
Airguns by Make and Model => Benjamin Airguns => Topic started by: WrongSide on February 12, 2021, 08:57:09 PM
-
I recently acquired an early 90s C9 Silver Streak. It has a very slow leak (sounds good when dry firing right after pumping 5 times, and still holds some pressure after 4 days but with noticeably less power).
I also have an early 2000s Benjamin 392 that I resealed last year that does not leak.
This is my first Sheridan, but I immediately noticed how much easier it is to pump compared to the 392. I've lubed the pins on both airguns with 30wt ND oil, and both sound pretty strong when I dry fire immediately after equal number of pumps (no .20 pellets to test velocity with).
Shouldn't they require the same amount of force to pump, or is it common for one to be easier to pump than the other?
The Sheridan has a soldered valve while the Benjamin has a brass cartridge valve in case that matters.
-
The soldered valve guns are easier pumping than the later removable valve guns. The soldered valve guns had a smaller, weaker spring for the intake side, and a stouter spring for the exhaust side. The removable valves like your 392 just have one longer, stout spring that works for both intake and exhaust. This means that for the initial few pumps, you're fighting that stronger spring to open the intake seal to put air in the valve. After 3 or 4 pumps, both models are probably equal in how hard they are to pump because now you're fighting against the pressure that has already built up in the valve.
-
Sounds like the streak is a canadate for an alcohol flush, Here is a more recent post on it with links to others.
I have brought back some basket cases to serviceable condition, and had one that all it did was help clean it up for a reseal, so worth a shot either way.
https://www.gatewaytoairguns.org/GTA/index.php?topic=178363.20 (https://www.gatewaytoairguns.org/GTA/index.php?topic=178363.20)
-
I would only make sure some oil got down around the pump cup. It sounds pretty good to me.