carbide rear brakes
 

Ours has quit working right or maybe I can't adjust it right. Looks like you loosen the locknut then turn the bolt to get a little more rear brake? Or is that just for the parking brake? If it is than I think something screwed up with the caliper. I took it off, cleaned everything, replaced the pads and bled the line but it still doesn't have much rear brake. It looks like the brake is only pushing on the rotor from one side? The caliper seems to flex to one side kinda. Should I just get a new caliper and where from?

if your caliper is like mine on the hammerhead, there are two pins that the pad slides back and forth on when the brakes are applied. those pins need to be lubed or they will hang up. since you have cleaned up the caliper, did you lube those pins? if they are dry the pad will stick and wear un-even.

The caliper should move / slide. It will appear to kick over just a little bit though just by the nature of its design. For the adjustment, you loosen the locknut, turn in the center screw by hand till it bottoms out and then back it off just a tad a lock it down.

Rear brake (parking)
 

I have an ASW Carbide 150, my son has a similar buggy but I forget the make. On both karts we have had trouble adjusting the parking brake. If we adjust it tight enough that it holds when parking, the the calipers rub and overheat the rotor when the brake is released. I finally took the hand lever apart and removed the compression spring in the housing. I dropped in a few lock washers (effectively shortening the spring) then readjusted the brake at the rotor, making sure that the bellcrank was properly positioned for the actuator. I shortened the spring at the bellcrank just to make sure that the inner cable was releasing properly. The adjustment now needs to be very precise so that the brake is fully on when the hand lever is at the detent, and the stop bolt does not allow the the lever to overextend and damage the cable.

best thing to do is pull the rear brake down
lube the pins w/lithuim grease put back together
go for a short ride then adjust the rear brakes