Well, this is my first post, and have to say, this board rocks!



Ok, here's my problem. I replaced the master cylinder the other
day, and now the brakes are sticking after just a few miles of
driving. To the point that the brakes themselves are
burning.



I bench bled it, and installed it and then bled the brakes, all
right. Its like the piston isnt retracting on the calipers.
So I replaced the Calipers. Well, its still doing it. Any
ideas? Could it have something to do with ?hydroboost? I
have no clue what hydroboost is. I dont even know if I have
it. All's I know is that the master cylinder that I got was for
hydroboost. Its nearly identical to the one that was on there,
but I wasnt having this problem before I replaced the Master cylinder.



Any ideas? Could it be a defective Master cylinder? Thanks alot everyone.



Guipo

It sounds like the master cylinder is not allowing the pressure to be released when you let off on the breaks. If I am not mistaken, there is an orifice in the master cylinder that allows the pressure to bleed of slowly. Jack up the front end and apply the breaks. Then try turning the wheels. If they will not turn, try cracking the lines at the master cylinder and see if you can turn the wheels then. If you can, I would say you have a bad cylinder.
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I have also seen the rubber hoses from the body to the wheel cylinder go bad and act like check valves. The way to test them is to crack the lines at the master cylinder – no pressure, then crack the bleeder at the wheel cylinder. If the breaks release then you know it is the hose.

The hydro-boost system is nothing more then the power assist for the breaks. It runs off the power steering pump since a diesel has no vacuum.

I think its the master cylinder, even though its new. it didnt start until I replaced the old one, so thats my guess too. I've only had the blazer since monday, so lots to do to get it up to speed. Thanks for the input!