Removed front wheel and struggled to get the caliper back onthe disc. I had a pad fall out and i struggled to put them back together. Now the brake lever has no pressure on it and the piston doesnt push out now. I am an absolute brake novice. I did unscrew the banjo screw on the brake lever so i could push the piston in.... I hope i didnt screw them up! By the way the bleeder screw wont budge so i cant even bleed the brakes.
Noooooooo! You don't need a new caliper, you just need to bleed your brake. When you loosened the banjo bolt, you introduced air in the system and that's why you have no pressure. Sometimes if you pump the lever around 300 times, you'll build the pressure back up. Another thing you can do is to squeeze the brake lever and wire-tie it that way and leave it over night. Sometimes that will get the air up and out.
To loosen your bleeder screw, clean around it with a small brass wire toothbrush and then spray penetrating oil on it. Use a good quality, Sear Craftsman or better, box end wrench and apply pressure -- right tighty, lefty loosey. Don't hammer on the wrench but keep heavy pressure on. Crack! The screw will come loose.
Now is a great time to rebuild your front caliper. A caliper rebuild kit costs around $25 and rebuilding the caliper is easy even for a newbie.
Once you are able to crack the bleeder free, don't continue to unscrew it. You are not completely out of the woods at this point.
Work it out slowly, by going back and forth, unscrewing and then screwing back in. And apply penetrating oil as you do this.
Get yourself a new bleeder, don't try to re-use it.
What I do with used bleeders is clean and drill them out and use them for my initial vacuum bleeding. I bleed with the vacuum pump until no more bubbles come out and then switch to a regular bleeder for the final bleed. That way, I don't draw air in through the loose threads of the bleeder. I know about using teflon tape to prevent the air leak around the threads but this way I'm sure the bubbles are from within the system.