The Crosman seal (Part No. 38-128) is a face seal that presses into the CO2 valve of your airgun. While these seals are durable and typically last a long time, they can wear out over time, especially if you notice CO2 leaking rapidly or slowly. Follow these steps to replace the seal and restore your airgun’s performance.

Works for the following Crosman models 

Crosman 357 (CO2 revolver) 

Crosman 38T (Target model, second variation) 

Crosman 38C (Combat model, second variation) 

Crosman 44 (second variation) 

Crosman 99 

Crosman 454 

Crosman 500 

Crosman 1008 (RepeatAir pistol) 

Crosman 1077 (RepeatAir rifle) 

Crosman SSP250

Tools and Materials Needed

• Replacement Crosman seal (Part No. 38-128) – freshly manufactured and unused.
• Screwdrivers (flathead or Phillips, depending on your airgun model).
• Small hex wrenches or Allen keys.
• Cart Gun Oil (or equivalent CO2 lubricant).
• Cleaning cloth or rags.
• Tweezers or a small pick tool.

Steps to Replace the Seal

1. Prepare Your Workspace

• Work in a clean, well-lit area with a flat surface.
• Ensure your airgun is unloaded and depressurized to avoid accidents.

2. Disassemble the Airgun

• Refer to your airgun’s manual for disassembly instructions.
• Typically, you will need to remove the CO2 cap and detach components to access the CO2 valve.

3. Remove the Old Seal

• Locate the face seal inside the CO2 valve. This is the component that ensures a tight seal around the CO2 cartridge.
• Use tweezers or a pick tool to carefully remove the old seal. Avoid scratching the surrounding valve area.

4. Clean the Valve

• Use a lint-free cloth to clean the groove or area where the seal sits. Remove any debris, dirt, or remnants of the old seal.

5. Install the New Seal

• Lubricate the new seal with a drop or two of Cart Gun Oil to ensure smooth installation and prolonged life.
• Press the new seal into the groove of the CO2 valve, ensuring it fits snugly and evenly.

6. Reassemble the Airgun

• Put the components back together in the reverse order of disassembly.
• Securely tighten the CO2 cap after installing a cartridge.

7. Test Your Airgun

• Insert a CO2 cartridge with a drop or two of Cart Gun Oil applied to its tip.
• Test for any leaks and ensure proper operation of the airgun.

Maintenance Tips

• Always snug up your CO2 cap when installing a new cartridge to maintain a tight seal.

• • Apply 1–2 drops of Cart Gun Oil to the tip of each CO2 cartridge during replacement to keep the seal lubricated and extend its life.