I picked up this 73 Blazer from this guy who did the disc brake conversion on the 14bolt he put in it, one problem, this truck dont stop for shit!! OK it does stop, but it takes along time to,.. Pedal pressure is light, almost no resistance, oh and by the way the tires arnt that big, just 35" radials.

So doing a little trouble shooting,and after reading some tech arcticles, I have run into some questions..

1) When doing the Disc brake conversion, do you keep the stock proportioning valve under the front crossmember? ... cause if your suppose to this guy didnt on this truck, he eliminated it and made his own "T" distribution.
He told me that the stock proportioning valve, gave to much residual pressure and kept the rear calipers locked up all the time.???

2) About the pedal pressure, dood told me, the cam was robbing all the vaccum, makes sense, it is a pretty lopy cam, but is there a way I can check how much vaccum im getting to the booster?

3) Dood also told me I can improve the braking by getting a master cylinder from a old school caddy with 4 wheel disc brakes, Or any gm master cylinder for 4 wheels discs, he told me the master cylinder will put more pressure to the rear brakes.

so if anyone has any info for me, Id appriciate it.

Tom-

how big is the cam?

every thing else should just be bleedin issue.

i put them on my 3/4 lb and they worked great right away.

either hes an idoit or the only one ive ever heard of having any thing wrong that wasnt fixed by bleeding them. repeatedly.

Hello, I finally got my fawkin rear disks working, everything except the e-brake, but anyway the idiot probably didnt bleed the brakes right, you have to take the calipers off and turn them upside down to get the ait out of them while bleeding, it took about a 1/2 hour to get mine bled out and I have more pedal than I ever had with the drums, I havent replaced the proportional valve or mastercylinder yet, but I havent driven it that much yet and it stops pretty damn good on 42,s and 16 inches of lift on a longbed 1 Ton !!!!!! So I recomend bleeding them and I have heard a corvette master cylinder of the 1979- era and I believe there is no pressure difference there is only the resevoir size difference as disks use more fluid than drums, and as the brakes wear in the back you will run out of fluid if not constantly checking the level, the new master cylinder will have two spots for fluid that are both big, and I would recomend the rear add-on prop valve, I am adding one on my truck just to be safe and might mount it in the cab as I drive on the street a lot and go mudding in the mountains on the weekend, makes it easier to adjust for your driving conditions. Just a thought, hope this helps.