Front disk brake conversion on 4x4 Jimmy

[chadcampbell00]

Everything with my braking system is brand new. I bought the jimmy less than a year ago and the po had changed everything (booster, master cylinder, lines, drums, shoes). I thought that my back brakes were locking up too much so I put an aftermarket adjustable proportioning valve on it and realized that actually it's my front brakes that are not working. I tried adjusting them but they keep self adjusting themselves loose again. I hate to change everything since its new but i really need front brakes. With that said, would the adjustable prop serve my purpose or do I need a factory one? And a couple of you said I should change to brake lines also, is there a different size line for disk brakes and drum brakes or was that just to have new?