Brakes are locked up

[lives4huntin]

Hi. New to this group. I have a 2009 grizzly 550 with only 500 miles on it. The rear brakes have occasionaly made noise, but last weekend became a major problem. The rear calipers will engage, but won't disengage. I have had it torn down twice now... Completely changed fluid, bled, rebled, and bled some more, and the pucks still won't go back to their home. Had them out, and the o-rings are good. No leaks in the lines. No back pressure on the handle or pedal when pressed. I am at a loss for where to go next. The heat created when this all happened, melted the plastic "gaurds" around the brakes. The dealer said they see this when guys ride the brake. I know that this is not the case, because my wife was following me and never saw the brake light on. Any help would be much appreciated.

[desertdweller]

Welcome to the GC lives4huntin Don't forget to post a new member introduction.
It is very easy to have your foot on that rear brake and not know it.
You've had them suckers pretty hot, it may have worped the disc.???
Keep us up to date.

[grizzlymark]

the piston never really "slides back" it just is no longer forcing itself against the rotor when you come off the brake..

as far as riding the brake... do your brake lights work? when my left (rear) microswitch failed, You could ride the brake all day long and the brake light would never come on.

also, (thinking away from the atv so i have to try and remember) take the rear calipers off, and check/clean/lube/replace the guide pins

[AZ08Grizz]

Originally Posted by lives4huntin

Hi. New to this group. I have a 2009 grizzly 550 with only 500 miles on it. The rear brakes have occasionaly made noise, but last weekend became a major problem. The rear calipers will engage, but won't disengage. I have had it torn down twice now... Completely changed fluid, bled, rebled, and bled some more, and the pucks still won't go back to their home. Had them out, and the o-rings are good. No leaks in the lines. No back pressure on the handle or pedal when pressed. I am at a loss for where to go next. The heat created when this all happened, melted the plastic "gaurds" around the brakes. The dealer said they see this when guys ride the brake. I know that this is not the case, because my wife was following me and never saw the brake light on. Any help would be much appreciated.

1st, make sure rear master cylinder is releasing pressure in the line when you let off the brake lever. If it's OK then
check for a pinched/damaged brake line between the rear master cyl and rear brakes. Look closely at any hard lines to be sure they haven't been damaged by trail hazards. Check rubber lines closely for any signs of exterior damage that may have caused internal damage that would interfere with fluid flow.

[lives4huntin]

Thanks for the input. Did all of the above and a little more. Brakes are working, but still have a rather soft pedal.

[Mad Mike]

make sure the calipers a moving free on the slides. If they stick again open the bleeder and if they release it`s either the master or a collapsed line allowing fluid to flow only 1 way. I see flex hoses on cars do it a lot..

[keeter]

x2 on what madmike talking bout, flex hose will break down inside and the fiber lining will act like a strainer letting fuild travel thru and then collaspe to nothing not letting fuild back in. but this is new bike so shouldn't be issue won't stealership do anything due to issues other than disk!