The previous owner really did a number on this Trail Boss. Looks like he wanted to bypass the rear brake caliper (it was full of mud, the bleeder screws were broken off, and one brake pad was missing), so he cut the metal line from the master cylinder and crimped the line closed. This created good pressure up front and the master cylinder was getting the front brakes to grab nicely.

I replaced the rear caliper and fixed the line from the front junction. I bled both lines and also replaced the rear pads.

It seems like the system is working (brake light goes on when I pull hand lever or foot pedal), and it slows down the quad, but doesn't have nearly as much "grab" as it did before I "fixed" it.

If I engage either the hand lever or the foot pedal while I'm stationary, the brakes hold when I apply some throttle.

However, when I am riding, it seems as if most of my slowing down is due to releasing the gas and the brakes are only "grabbing" a little?

Is there an additional adjustment I can make?

 

Still sounds like you may have some air in the lines.On this system when working right,most of the stopping power is in the front,a smaller amount to the rear caliper. Something like 60/40 or so. A mityvac can usually remove all trapped air pretty quickly and make bleeding a snap.As far as the auxiliary/emergency brake,the small master cylinder was the weak point on seals sucking air,not building that much pressure.These are cheap on ebay or amazon if needed.