Dear Tony.
We all feel your pain.
Every one of us went thru the same frustrating moments at this point or another.
I would like to give you couple of advices before you give up.( And believe me, I was on the way to the store to get a case of dynamite more than once).
1. If it doesn’t work for you, walk away. Start over fresh tomorrow, I promise things will look different.
2. Take bmx672 advice, and replace the hoses as well.
3. Get that tool :
Amazon.com: Astro Pneumatic 9409A Hose Clamp Pliers: Home Improvement
No clamp is slipping any ware with that.
Good luck bro. just think of the satisfaction you’ll feel once you will complete the job