Brake seizing help!

sooo, just recently my brake pedal has been getting really stiff and the front passenger has been locking up. I have replace the caliper, pads, line and hose for the pass. side. it seemed fine at first then today i drove to school and it locked back up afer about 15 miles of driving. The guy i got it off of, Squeek, replaced the master cylinder and rear brake seals right before i got it.

I just cant seem to figure it out, seems like its fine until it warms up.

ANY IDEAS WILL HELP.
Thanks, Rob

Did you replace both sides when you replaced the front pads and calipers? You might want to check to make sure the piston isn't stuck. Only other thing I can think of is an issue with the brake booster.

No only the pass. side. and its still the only wheel to seize up. i bled both sides, but will probly end up putting a caliper on the drivers side when i get paid thursday. would changing only one cause a problem?

Also it feels like it doesn't have enough brake pressure w
hen its cold..

So i am pretty sure its all the brakes locking up.. the front just more then the rear..
proportioning valve? Booster?






And what exactly is this? lol

Did the previous owner say why he replaced the master cylinder? I wonder if it was an attempt to fix this issue

The last picture is your clutch resevoir (sp)

Oh shit. I put brake fluid in it......... What is supposed to go in it? tranny fluid? im gonna go drain that out now. .
and no, he said when he got it it barely had brakes... so he replaced it.

or wait.... ehow said to put brake fluid in it. lmao

And its also got new rear seals.

Ok. so i just went out and drove it around till it locked. and then pulled the vacum line off of the booster and it didnt release the brakes. wich in turn eliminates the bad booster.. then i pulled the line off of the proportioner and it released. so does that mean its gotta be the proportioner??