Brake Conversion

[Genes70pu]

Hi All: First I should tell my truck has been in storage for the past 10 years. I recently got it running again and I’m trying to figure out the brakes again.
I’ve got a problem with my them. Several years back I converted my truck to disk brakes using all the parts from a 71, 72 C-10. Most parts were new, just use the spindles and a few other part form a donor truck. Well I have never have been able to get the truck to stop as it should. I even when out and bought a new proportioning valve from Chevy. Didn’t want to use one of those adjustable types. Still no luck, it stop but not well. Back when I did this I use the brakes hose from a 73 cause I was not able to fine the exact ones from the 71 72 truck. Somehow I found out that they would work. I’ve check everything I can think of and still no luck. Any ideas what I should try now. Don’t want to replace everything again. I think it should work with most of the parts I have on it. Those brakes hose are on my mind.
One more thing I need to add, when I bleed the brakes the last time the pedal didn’t go all the way to the floor. It bottom out about 1 ½ inch from the floor. Dose this mean anything to anyone?
Thanks for looking Gene.

[69nova]

I just want some clarification. When you say it doesn't stop as it should, do you mean spongey pedal, pedal fade or hard pedal with no results. Give a little more explanation. Did you add the power booster assembly when you did the conversion? If so is it holding vacuum because they are prone to leak over time? Did you use the pedal rod from the other truck because it may need adjusting to get full travel out of it? You didn't say anything about engine. A big cam shaft will rob the vacuum on power brake setup. Did you add a new master cyl?

[Genes70pu]

Thanks for replying hope this isn’t too confusing for you to understand, I’m not the best at getting my point across. Well I would say a hard pedal with no result. You can’t lock them up, it just won’t happen. Yes I did add a power booster and it’s holding vacuum I think. I don’t hear any noise from it. Master Cylinder was just replaced when I got it running again. It’s a 350 4 barrel and I do have a small cam in it, I lost the paper work for it, but when I bought it I know it was just a RV cam I think they call it at the time. This was about 10 years ago. I mention when I posted that I use the brake hoses from a 73 C-10, and after I posted I was looking at Autozone, I see that they have the right hose now. I don’t know what difference they would make. I might make that change this weekend. Back when I did all this to it I didn’t have the internet to help me. I had to find info where ever I could. I can’t remember where I found half the info I needed at the time. I know I had to replace the centerlink and tie rod ends because the taper on the 71-72 spindle where different that the stock 70. As far as the brake rod, I think I use the right one, I know back when I was driving it about 10 yrs ago I bought a new booster and when I got it running this time when I replace the master cylinder I measure the rod and how far it was sticking out of the booster and how deep it needed to in the master cylinder and I think I’m on the money. As I mention in the post, the pedal done not go to the floor when I bleed the brakes. It bottom out before it hit the floor. Maybe there something with the travel of the pedal. Thanks for helping.

[rsavage]

If you have a hard pedal and it doesn't seem that the booster is applying assist (doesn't feel like you have power brakes) try adjusting the rod that comes out of the booster into the back of the master cyllinder. You should be able to unbolt and move the MC carefully away enough without unhooking lines to adjust it out until you feel normal assist. Had a similar problem with a new booster on my '70 shortbed 4X4. Adjusting the booster rod fixed it. Of course, mine are drum/drum, but it's a simple thing to try. Note: if you adjust it out too far, you will have your brakes engaged all the time. Hope it helps.

[69nova]

I agree with rsavage in that it sounds like you are not getting power assist and you only have the default manual brakes. I don't think its the lines but I've been wrong before and plus it would give you peace of mind by replacing them. I would concentrate on the booster rod and available vacuum. I have a 72 c10 swb step and did an engine swap with what I thought was a small cam setup (rv cam) but after the swap I lost my power brakes. I had to add a vacuum can to regain my power brakes. Good luck with your brakes and let us know what you find.

[moonshinner]

if it did not have pb before the rod from the pedal may need to be lower on the pedal some pedals have 2 holes for the rod one for power the other for manuel if it is in the wrong location it will put the rod in a bind

[Genes70pu]

Thanks for all the replys, I think you all are on to something with the brake push rod. I seperated the M/C from the booster, took a bunch of measurement and I think its too long. I shorten it and tried driveing it with out bleeding the brakes again. It dose feel better and I can lock them up in reverse, not forward. I hear the rt front wheel lock up. So I think you all are on to something. I tried my local parts house and they can't get those front brakes hoses, so I will try elseware online. I'm not sure on the booster yet, but maybe a problem there too.