Rear brake 2000 F4

I'm having a little trouble with my rear brake on my bike. When i would apply on the back brake I would feel nothing and then once the pedal was pushed all the way down then the brakes would lock up.  So i purchased new back pads and bleed the brake lines took it for a test drive and still the same thing. I called a honda tech and he said it sounds like there is still air in the brake line, that it doesnt sound like anything else. So we bleed the brake line again and nothing. Anyone know what else it could be?

when did you get the bike?
 
the rear brake usually sucks like that. you don't feel much when you step on it and then it locks.

Bought the bike last year. Bike has 30,XXX miles on it.

so it just recently started doing this right?
 
check the pins that hold the pads, see if it's pitted, etc. i usually put some grease on this to makes ure the pads are able to move.

yeah, lube the sider pins up good. Then check the rotor to make sure its not warped.

oh and also check to make sure the pistons are not gunked up around the sides. clean that part out and also lube it if you want...but no crazy lube that will fling. you don't want this stuff on your pads or your rotor.
 
could be possible that the piston is stuck until you put lots of pressure on it then it comes out.

+1000 on all that, and use the front more. The front is your real stopping power, the rear just assist n stabilizes, used for low speed manuvars, grass, gravel etc.

Thanks guys I'll check them out.

Brake return spring look okay?
 
Air in lines can do some weird things... it's also not a super simple process when you're just using a wrench for the bleeder valve.  Speed bleeders are great.