check to see if you have a frozen caliper and check for rust binding caliper. this is assuming no brake line has been tampered with.
the proportioning valve is in abs unit an dprobably not that. check bushings for calipers as wellmake sure they are lubed.

Answered by hmac300 (expert)
17,932 answers provided

All the above suggestions were performed at the time of the front end bushing/bearing replacement and frontend alignment. The proportion valve is an ABS realated component? The ABS light has been on for quite some time... well within the last couple of months and was gonna replace both frnt hubs here in the next 3 weeks before it gets too dang cold

Response from Oldnavy39
3 questions asked

have the abs scanned to see where the problem is first. dont' spend money unecessarily without doing that.it may be a sensor not the hubor the sensor may need cleaning

Answered by hmac300 (expert)
17,932 answers provided