Hi there!
This is my first post here! I am hoping to find some help on a interesting problem...vehicle is a
98chev blazer 4x4
I changed the brake booster last fall due to a internal leak, and boy it was nasty getting that thing in and out, actaully had to do it twice since i cheaped out and got one from a wrecker and the dang thing had the same problem, so i shelled out the 200bucks for a new one. problem fixed.....but now since Ive done that, the front brake will randomly apply themselves, usually only during hi-way speeds and after at least 20mins. The whole vehicle starts to shake and max speed becomes about 40mph. I only figured this out after quite some time, i walked around the to the front and i could feel the heat just radiating off the front wheels!!!
What on earth could cause this???
Ive disconnected the abs fuse, still occurs.
Ive bleed the brakes..still occurs.

So now this is where im heading, during the booster change the master cylinder was shoved out of the way, and there are these stainless steel brake lines that come off the master cylinder to the abs unit. I am thinking that i somehow kinked/collaspsed one of the hoses, or damaged the master cylinder somehow???
Man ive been scratching my head over this one for a long time!!

Anyone have some thoughts or ideas? Think im way out to lunch here?

Thanks

 

Is the check valve working correctly where the vacuum hose goes into the brake booster?

And if those lines are damaged it could cause brake drag.

 

I'm thinking possibly a collapsed brake line by a/the calipers. Rare, but it does happen.
Is the spring that returns the brake pedal ok? If it's weak for some really odd reason the weight of the peddle could be slowly applying the brake. <--- That thought was from the far reaches of space - WAY out there for likely hood!!