doh! look at what I brought home

[shawno72]

Originally Posted by Longhorn Man

drum/drum trucks do NOT have a proportioning valve, just a distribution block.
Pres the pedal down with your hand. Is the pedal real easy to pres and then you get reisitance 1/2 way down? You should only have free pedal travel the first 1/2 inch or so. I've seen this cause what you describe.

I stand corrected. Learned something new today. Thats why I love this site. Longhorn man I just thought the block on the side of my 68 master was the same as the one on my 72. That explains why I have to change it to a prop valve when I do my front disc brake upgrade. Thank you so much for clarifying that.
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[juanz1947]

Nice truck Ive always wanted to go to Alaska soon some day I hope

[a2tripp]

I think my m/c is the same, maybe a larger resevoir, but the way the lines go down to the dis block are identical, I also have a booster

[a2tripp]

Its seems the distribution block is there for safety, isolating the front/ rear, I think the sensor trips a light when theres pressure loss, if thats the case I dont see why that would be causing my issue.

I really wish I had a book or a FSM, even if I order one it willl be a while before it get here. I am on a island about 600 miles from normal civilization. Luckily this forum and the minds on here are way more helpful, thanks for your help!!

[VA72C10]

Nice truck. Hope you resolve the brake issue soon. Take off the drums and take some pictures and post them on here....there's a bunch of knowledgeable guys in this thread who could help out when they have pics to go by.

[RCbowtie69]

Nice buy & a good looking truck.Keep on truckin'

[a2tripp]

well I took a look at everything, made very little progress. First off those bleeders valves are horrible to get to, especially when there rusted and deformed, uh! Anyways got the drums off and like the po said everything is new. No signs of leaky wheel cylinders and everything appears to be hook up right. I bleed the brakes and loosened all the adjustments. It was much better but still locked up. Took a look at the pedal adjustment and got stumped. The PO has a bungee as a return spring but pedal braket does not look like its adjustable, so ??????
So after making a lot of reverse stops I noticed it was better but still not good enough for winter driving. Drove by les scwab on the way home and the manager is a owner of a 68. He said my problem was the adjustment on the drums, that the distribution block is not the cause. He explained to me the if the front brakes are locking up when the pedal is almost to the floor than the rear need to be adjusted, blah blah blah... I told him that I just readjusted the drum so to the point were there was no drag. He swears up and down that this is a common gm drum/drum issues and it was an adjustment issue. So I will drop it off tomorrow and see what he can do....I shamed to do it, but the brakes need to be right to drive on the icy roads up here.

I managed to grab an adapter for my carter afb. mr gasket#1932. not a single person at napa new if this was a squarebore carb to qjet manifold adapter.

[C5Phil]

subscribing--

[a2tripp]

well it been 2 weeks and I am still at a lost with the brakes. So shortly after my last post I adjusted the brakes and brought the front shoes almost all the way in... I had way better brakes but the front still locked up. Took it to les schwab and the first mechanic couldn't figure it out and told me I needed a new prop valve. So out of stupidity I ordered the $100 distribution block and installed it, gues what, the old one was fine, made no difference. So took it back to les schwab because they have another mechanic who knows brakes??????? he had it for 3 days. called me up and it was fixed, resurfaced the new front drums, power bled the brakes, and adjusted the brakes. $300 later I was off. Well the brakes were better, better than they have been. Put about 50 miles on the truck and its back to locking up. So I am out $400 good thing it grows on trees. So after banging my head for not going to disc I am writing this. What could possibly be wrong, This just does not make sense.

Tomorrow I am going to dig back into it, this time in the cab at the brake pedal. I noticed when I was wiring the electric choke that I have a couple of bungees working as a return spring on the brake pedal. Is this a common mod

c'mon drum guys out there, I can't be the only one!

[DaBigKahuna]

I haven't read the whole thread but what kind of shape are the soft lines in? Over the years they can start to swell and reek havoc with brakes.

[a2tripp]

Originally Posted by DaBigKahuna

I haven't read the whole thread but what kind of shape are the soft lines in? Over the years they can start to swell and reek havoc with brakes.

all new

[Vintage Windmills]

How bad are the tires? Even if they show tread they could be old and hard and not grip well. Also maybe try a different set of shoes? Just thinking out loud here. Curious what it will end up being.

[a2tripp]

I swapped to studded tires since I had the truck but both set have had good tread but were probally old. The shoes/drums/hoses/wheel cyl were new napa ones. its just weird....

thanks for the replies everyone