So my bikes was in getting other stuff done and I asked to look at the rear brakes and do what's needed. They replaced the hardware and pads and flushed it. I only have rear brakes(it's a chopper) and as soon as I left the shop the rear brake seized. I got it free and circled back but the shop was closed. I rode home and kept testing it. It's so sharp as soon as I touch the pedal it stops or locks. Once I got home I circled around front of my place and at one point I hit the brake and it wouldn't move. Was solid not braking. I opened the cover and pumped and no bubbles and I haven't seen any issues other than how hard it brakes right away. What the heck did they do and can I fix it myself? I don't trust them to take it back there. It's a 79 shovel chopper not sure what caliper it is but in the receipt from them it says 87-99 mounting hardware so I guess it's 87-99 caliper. I was used to a more active brake, harder you press harder it stops. Now it's stop/lock or nothing.

Please se advise on what I can do to fix it cause it's my only lifeline

 

Ride a while today and all seems okay.