Recently we swapped a 14 bolt out of a 79 K20 into my 71 K20, replacing the original Eaton HO52 that blew up. The HO52 had 1/4" brake line while this one has 3/16". The proportioning valve and everything is unchanged. The wheel cylinders were also leaking pretty badly, we replaced those, the shoes, and the hardware. But they still lock up if you brake hard! Do the shoes need time to break in? I was wondering if the smaller 3/16" line is causing too much pressure to be sent to the rear, since the proportioning valve is set for all 1/4" line. Also, the brake light is not on. I get my license in a couple days and definitely want everything working correctly so I don't wreck it.
Thanks!