First off, i'd like to say hi. I'm new to the forums.

I have a question about the brakes on my atv. While cold or after some slow riding the braking is fine.. but after long rides or under heavy braking the pedal for the rear becomes stiff. It feels like when the brakes are pumped up all the way on a car.

You can stand on the pedal and still not stop. But the brakes are locked in the rear.
After a few miutes the brakes cool and release.. but today was the second time that it left me with no brakes coming down a hill.

I use the front brakes also, but I'm used to motorcycles where you used the pedal for your main braking.

I'm mainly asking what would cause the brakes to pump up so tight and lock up?
I have thought maybe the brake fluid is getting too hot and it's holding pressure. Also thought it may be air in the lines, but couldn't get any bled out tonight.

Or am I just riding wrong? Should I use the front brakes for all my stopping?
I'm going to do a full system bleed tomorrow and see if it helps the situation.
If anyone has had this problem and has an answer, or even idea I'm open to suggestions.

It's a single caliper rear setup, so there isn't but so many places to be giving me this problem.

Thanks in advance, hope to hear something tomorrow.

 

what kind quad is it?


that shouldent happen on any quad, somthing is wrong.

air could be it.

 

Well I think it's actually an import. It doesn't have any stickers on it..

The brake system is almost like a raptor though.

Single master cylinder, single caliper disc brake on the axle.

None of the 2 hoses is more than 12 inches.. so I think I'm going to try and bleed it up with a cup of brake fluid and a hose. Maybe that will help work the air out... I'm not much on quad brake systems, I'm more of a car mechanic.

But it should be the same principals I would think. It's not like a vacuum boosted cylinder, so there's no vac line to be giving me problem.
It wouldn't bother me if they were this hard all the time, then I coul adjust the pedal out to work with it.
But if I adjust it out for when they are hot, then when they are cold it doesn't make ANY contact.

 

Take the caliper off of the bracket, and check the sliders. They may be rusty or worn crooked, and get hungup when trying to return.

 

I got the caliper off and the sliders were kind of stiff..

The rear brake isn't even working now though.
Even at full stroke the caliper isn't even attempting to close.
It gravity bleeds fine.. but nothing happens when you hit the brake.

I'm thinking of doing a full system bleed. Any clues on where to start.. and how to get the best bleed?

 

With the caliper off, I held the bleeder end up and let it gravity bleed while constantly refilling the fluid.
After a few seconds of nothing but air, in between spurts of fluid it wasn't giving me anymore air.

The brakes now havebraking ability through the full stroke of the master cylinder, rather than half like before.
So I'm almost certain it had air in the lines..
I'm going riding tomorrow again, so I'll see if it still pumps up hard and locks the brakes again.

 

Not sure on your bike but on a lot of them the rear brakes are hydraulic when using the hand lever and cable operated with the foot lever. You get better br4aking action on the rear with the hand lever.

Jaybee

 

Well, guys.. it's stopping perfectly, after adapting some honda pads to fit in the calipers.
Hasn't givin me anymore problems so far, and it's been on a few 12 and 14 hour rides since then.

Now I am having different issues.