brakes locking up?

[xyzse]

from leaving the driveway it drives normally and brakes normally.after i drive it for about a mile or 2 it hesitates alot and the brakes get real hard,when i push down on them they only go down about a inch.

[Tippey764]

brake booster is going bad, its leaking or somthing now giving you any power assist

That or your driving around with your foot on the gas thus depleting the vaccum in the engine.

[Monza]

If it's cold where you are sometimes the rubber hose that goes to the booster can get water in it and if it's cold enough will freeze and block vacuum getting to the booster.

Has not happened to my accord, but used to happen all the time in my sidekick.

[xyzse]

the brake booster and master cylinder has only been in there for about a year and a half.im pretty sure thats not the problem.i think i need to bleed the lines,maybe dirt or air in them?

[Old Dog 61]

When you say the brakes are hard....is the car acting as if the brakes are dragging? As if you were driving with your foot on the brake, needing extra power to drive down the road? or is the only symptom a hard brake pedal?

[Monza]

If you had air in your lines the pedal would be soft, going to the floor not hard as a rock.
I'm also assuming that the car didn't stall at the same time as your pedal went hard, right??

[Khristaphoe]

I had the exact same symptoms. I had my mech change the brake booster. Fixed.

[Old Dog 61]

I would suspect the booster if your only symptom is a hard brake pedal. The booster might not be that old....but things do go bad! MAYBE the diaphragm has failed in a way that you have some vacuum to begin with but can not keep vacuum because of the usage as you continue to drive

[199Dakord]

I just fixed that problem on mine I had to change my master cylinder and I had to get a caliper kit

[xyzse]

i bleeded all 4 brakes at the wheels,before the the fluid was just dripping out but i got it to jump out when bleeding.i think the system was clogged up or something.the car has been sitting up for a couple of months.could that have been the only problem.or should i just change the master cylinder to be sure,i have warranty.how do u know when your calipers are bad?thanks

[Monza]

i bleeded all 4 brakes at the wheels,before the the fluid was just dripping out but i got it to jump out when bleeding.i think the system was clogged up or something.the car has been sitting up for a couple of months.could that have been the only problem.or should i just change the master cylinder to be sure,i have warranty.how do u know when your calipers are bad?thanks

A leaking master cylinder would give you a soft pedal. As for knowing if your calipers are bad, there's not much to them but you can remove them from the holder and inspect them.

Check the rubber boot around the piston for rips and tears, get a pair of channel locks and gently push the piston back into the caliper it should push back quite easy.

A seized caliper will be very hard if not impossible to push back in. BUT a seized caliper will also give you a soft pedal. I would be looking around the booster for cracked or frozen vacuum lines or the booster itself.