GMC c1500 -83 rear brake drums

[Swed-Chevy]

Hi , i was showing the truck at our two year check for safety things like brakes and it showed that left rear brake was poor. Last time they checked this the brakes was just fine and they approved the truck for driving.

https://www.mynewsdesk.com/se/opusbi...en-del-4-47583

Adjusted the rear brakes and should bleed the fluid but in the left wheel cylinder there was no fluid at all , we must pump the brake pedal several times to get fluid coming out of the bleed nipple. Can not see any leakage anywere so
this was strange , have never seen this before.

Checking level in the fluid cannister at the mastercylinger often. We bleed both rear drumbrakes but still poor ( uneven )brakes .

Any tip about this would be great.