front brakes lock

i was trying to my car this past weekend, it was able to drive perfect but when i started to dive a few houses down my front brakes and only my front brakes were getting locked finally as i was trying to put that sucker in my garage they did get lock, why? what would couse this? i did put new calipers, brake fluids are ok.

 

So when you put your foot on the brake the front wheels lock up??

 

yes, after me trying a few times pressing the brakes and driving it, they finally locked.

 

Simon, im almost sure that he has disc(see quote).... not to mention you cant assume all 75's had disc because half of them didn't. Just some FYI for thought...

Since the calipers are new, try the brake hoses or M/C

 

front brakes are disc and rears are drums.

 

Rusty Rotors?? maybe from sitting ?

 

its just being sitting for about a 1 month.

 

Was it in a damp place? they can rust pretty quick. Get under the front and have a look.

 

the discs were rusted, you think thats the problem?

 

Proportioning valve bad?

Disc being rusted shouldnt be a problem. The will rust as you wash your car or overnight in a dense fog. Theyre made of iron. The first time you hit your brakes it all comes off.

 

One or both sides locking? Have you replaced the rubber lines? How old is the master cylinder? Faulty new calipers?

 

both front brakes, i really dont know how old the m/c is, i just bought the car last year in early summer from a guy in tx.

 

if it's both, i'd start with the M/C. they're only $20 (or less) from your local parts house

 

have you bled the brakes properly? air in the lines would do it as well

check the rotors.. a warped rotor would def lock up

 

My first instinct is that you have a caliper/rubber brake line problem, but I'd otherwise have to agree... I've had both the master cylinder and proportioning valve go bad. When the prop. valve went, the pedal just got hard as a rock and the car would barely stop, or with only a very slight bit more pressure, the brakes would just flat out lock up. When the master cylinder went, the brakes were very unpredictable, you'd hit them one time and the car practically had no brakes, then the next time you'd barely touch them and it would about throw you through the windshield.