Replacing the Piston seal on a New Style Gamo with the new two pin Receiver.

I have over 20,000 shots through my Mach 1 which is less than two years old so I figured the piston seal had to be bad. The thing is the rifle is extremely accurate and shooting very smoothly except for some roughness in the trigger. While it has lost about 40 fps it shoots better than when new. So I watched the you tube videos and figured I was ready. WRONG! The videos were of the old one pin models. I figured I would list the differences at the beginning which are. The older models have one retaining pin under pressure which when removed allow the trigger assembly as well as the piston and gas ram to be removed. The new models have two pins. The one toward the but end of the rifle is not under preload pressure and can be driven out to remove the plastic end cap as well as the trigger assembly. The plastic end cap on older models was not retained by the pin. This is handy if you want to clean up the trigger because you don't need anything to compress the gas ram. After removing the first pin and trigger assembly the gas ram will have to be compressed enough to get the pin out and unlike the old model the ram has to be compressed with a two prong tool and compressed enough to get the pin out which has an area removed the allow the fitment of the gas ram retainer cup. Compressing slightly will loosen the pin but not allow removal. You have to compress enough to allow the pins cutout to pass the retainer cup. The other difference is the barrel removal. I have read that barrel removal on Gamo break barrels is difficult to impossible. Not this one. Push one pin out and the barrel comes off. There appears to be a brass bushing that the pins goes through. Also as the photo shows the end cap is retained by the pin. Also as you can see the cylinder is in excellent shape for over twenty thousand shots. The piston seal looked much better than most I saw on videos and the piston had no scarring or galling. I took pics of both sides. You will however see some galling on the gas piston on one side.As you can see for as hard as this rifle has been used it seems to show much less wear than one would expect. I was not expecting to need a two pronged tool to compress the ram so to get the job done I used a socket and crows foot from my auto mechanics tool box. I would like to give a shout out to Custom Air seals of Australia as when I got the pin loose but could not remove it I shot them an Email with my problem and got a reply and several pics from Laurie very quickly. Great customer service as well as quality products. I know many people are down on Gamo for their own reasons but when I wanted to get into air guns I didn't belong to any forums so I just took a chance on the Mach1. I guess I just got a good one but I really like this gun and now that it is back together I look forward to many more shots.