Proportioning valve issues

[redSUPRA '88]

so i just redid my whole front end braking system (New Master Cylinder,brakelines, calipers, ceramic pads, clips) and we bled the system. for some reason after braking the equivalent of a mile my brakes become uber sensetive. like if i push the pedal down just a little its almost as if i slammeed it down all the way. along with that the caliper is continuing to apply pressure while im driving so i get a burning smell and the rotors have a rainbow effect to them. ive heard the proportioning valve could be going bad..... is this the case? or am im missing something.

 

[Poodles]

Sounds more like the brake booster adjustment. http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=BR&P=21

 

[redSUPRA '88]

Ok i'll check it out later, im in skool so the link doesnt work.

 

[spencyg]

Yes, and the more fluid in the brake line heats up, the more volume it takes up. Actually, the fluid doesn't expand enough to do this on its own, but if you have a little bit of air in the line, you're going to see expansion when it gets hot. Brakes that drag are known to "self apply" periodically, especially when not fully bled. Sounds like you have a couple things going on here. Also check your calipers are sliding and not binding.

And obviously, don't drive the car until you fix this problem. Brakes are nothing to goof around with...

SGinNE

 

[redSUPRA '88]

yea i know, and it sux cus i love my poopra. anyone here have a proportioning valve?

 

[Poodles]

Proportioning valve wouldn't cause that issue. Most likely causes are air in the lines or booster adjustment as that's what was changed.

 

[redSUPRA '88]

we did a brake bleed and got a ton of air out of the front right brake line yesterday. Probably gonna bleed the left side todayand see wat happens