OK here is how to fix a cupseal leak in your PT pistol.
1. Unscrew the cupseal counter-clockwise and remove the cupseal
2. The cupseal is actually two parts that are screwed into one another. You will have to unscrew the two parts form each other.
3. When these two parts are apart you will see an oring size 10 that needs to be replaced.
4. Replace the O-ring and reasemmble.
If you're having trouble working on your pistol or cannot find the correct oring call me @(877) 728-2243 via www.GatSplat.com
and I'll be glad to help you out.