2003 Chrysler Town & Country?

[Kim]

My 2003 town & country is having brake issues. It has been in the shop 3 times. The calipers (sp?) have been changed, the master cylinder has been replaced & they have been bled. The brake pressure lasts about 3 months then they go to the floor again. The shop that has been doing the work stated I may have to take it to the dealership. Anybody have any ideas of what could be going on?

 

[Michael]

could be a proportional valve, if it has drums in the rear the drums could be over sized causing the shoes to expand more and not full come back, causing a low pedal.