What brake setups do you have?

[87Skier]

I don't like the brake performance and pedal feel of my current set up. I have a 4x4 72, with front disc, rear drum, I've been through the whole system and everything is new but I'm getting tired of how hard the pedal is. If I'm doing 70+ it feels like you need to get both feet on the brakes to even get them to do anything.

So, what upgrades have you guys made? Do you like them? What did it cost you? Did the truck stop better? Worth the trouble?
I want to stick with front disc and rear drum, but want my pedal to feel like a normal vehicle. I'm considering trying to fit a brake system from a later 70's pickup, anyone had luck with this? Here is a picture of my booster and master cylinder for reference.

Thanks!

[RustyBucket]

Both of my trucks are stock pwr. disc/drum. Booster & master cyl. look pretty much like yours. I can lock the brakes on either one without a lot of pedal pressure. Are yours working right? I see your wire is off of the proportioning valve for your brake warning light.
Recently put new pads & shoes on the GMC. I found one of the rear adjusters was stuck and that brake wasn't working much. One wheel braking on the rear made it want to change ends without much pedal pressure. Stops much better now. We have '02 & '06 GMC's and the old trucks don't require any more effort to stop than the DD's..... just no anti-loc.

[special-K]

I've always been perfectly happy with the stock brakes on my '72 K2500, as long as they were in proper working order. And, the truck is still worked...hauling and towing. The same is true for all the K20/K2500s I've had (always had at least one)

[87Skier]

Originally Posted by RustyBucket

Both of my trucks are stock pwr. disc/drum. Booster & master cyl. look pretty much like yours. I can lock the brakes on either one without a lot of pedal pressure. Are yours working right? I see your wire is off of the proportioning valve for your brake warning light.
Recently put new pads & shoes on the GMC. I found one of the rear adjusters was stuck and that brake wasn't working much. One wheel braking on the rear made it want to change ends without much pedal pressure. Stops much better now. We have '02 & '06 GMC's and the old trucks don't require any more effort to stop than the DD's..... just no anti-loc.

Forgot to mention that was an old picture. Since I took this the master cylinder got painted and the combination valve was switched out. I suspected it was the valve that was causing the rock hard brake pedal. It wasn't.

I've asked this question before and many said it is the right one, but do I have the wrong master cylinder? Is there an easy way to tell the difference form the older drum only setup? Can one of you attach a picture of yours?

[michael bustamante]

i have a2wd disk drum set up but my master cyl, does not look like yours. I only have 1 retainer clip and the front resevoir is bigger than the rear. is that a trailer brake addition on there that is snipped?

[slikside]

Kinda hard to tell, but are you sure that the brake line for the rears, from the prop valve back is larger than the line for the disks up front?

I recently rebuilt my entire brake system (although not a 4X4), and the brakes really didn't feel that much different afterward. I guess they feel just like a stock '72 should. Just the limitation of design from more than 40 years ago. You can't compare them to modern braking systems.

But it does sound like your pedal is overly firm. Have you changed out all the rubber brake hoses? They can (apparently) collapse from the inside, while looking normal on the outside. So, if they've never been changed...

[87Skier]

Originally Posted by michael bustamante

i have a2wd disk drum set up but my master cyl, does not look like yours. I only have 1 retainer clip and the front resevoir is bigger than the rear. is that a trailer brake addition on there that is snipped?

I honestly have no idea what it is. When I changed out the combination valve, I left that off. It looked like something that might cause a leak later on. I didn't find any extra brake lines on the truck though. I will say that I believe something at one time or another was mounted on the front of the vehicle, so it might have something to do with that.

I was going to swap in one of those cylinders but a few people mentioned that in 72 either setup was common. When I got it, it had the same style master cylinder, and when I ordered a new one it was identical. Doesn't mean it is the right one though.

I changed all the rubber lines, calipers, wheel cylinders, master cylinder, and combination valve. I didn't do all this chasing this problem, I did it because it had been sitting for so long.

[72kool]

Mine is not 4x4 but the brake setup looks the same. A hard brake pedal is usually 1: drum brakes are out of adjustment and need loosened. or 2: an issue with the booster. these are vacuum boosters that run off of vacuum through the manifold/carb. I would check to make sure the hose going between these is solid and not cracked, make sure the plastic inlet on the booster is in good shape. if you know the booster is good, i would check that you are getting adequate vacuum from the engine to the booster at those speeds. how does the engine run? did you have anything done to it recently? I know that when i had my carb rebuilt, there was 2 gaskets in the kit and used the wrong one first. the difference was the vacuum port was different and it didnt allow adequate vacuum to the engine and brake booster.

[michael bustamante]

Originally Posted by 72kool

Mine is not 4x4 but the brake setup looks the same. A hard brake pedal is usually 1: drum brakes are out of adjustment and need loosened. or 2: an issue with the booster. these are vacuum boosters that run off of vacuum through the manifold/carb. I would check to make sure the hose going between these is solid and not cracked, make sure the plastic inlet on the booster is in good shape. if you know the booster is good, i would check that you are getting adequate vacuum from the engine to the booster at those speeds. how does the engine run? did you have anything done to it recently? I know that when i had my carb rebuilt, there was 2 gaskets in the kit and used the wrong one first. the difference was the vacuum port was different and it didnt allow adequate vacuum to the engine and brake booster.

looking at your pic i cant see where your vacuum line runs to. it should go to the back of carb i think

[72kool]

I believe i can see the hose connecting to a steel line like mine that runs to the carb.

[72kool]

another thought, it looks like new(er) booster and master cylinder. if you replaced either of those, can you confirm that the push rod is aligned correctly to the master?

[GRX]

Stock system on truck in my sig. 4 manual drums. Completely rebuilt including e-brakes. Stops pretty well. One mistake many make is not turning old drums unless obvious grooves are seen. Speaking as a machinist, will say they can and do wear uneven. Which often results in new shoes not riding square and fully across the entire surface of the drum/s. And you know what that means.

[Bigdav160]

Disc require more pressure than drums.

It's hard to tell from here but it looks like a 1/2 ton brake booster.

[87Skier]

Originally Posted by 72kool

Mine is not 4x4 but the brake setup looks the same. A hard brake pedal is usually 1: drum brakes are out of adjustment and need loosened. or 2: an issue with the booster. these are vacuum boosters that run off of vacuum through the manifold/carb. I would check to make sure the hose going between these is solid and not cracked, make sure the plastic inlet on the booster is in good shape. if you know the booster is good, i would check that you are getting adequate vacuum from the engine to the booster at those speeds. how does the engine run? did you have anything done to it recently? I know that when i had my carb rebuilt, there was 2 gaskets in the kit and used the wrong one first. the difference was the vacuum port was different and it didnt allow adequate vacuum to the engine and brake booster.

Sorry for the delay in getting back to everyone. I have 20 inches of vacuum at idle. Brake booster is hooked onto back of the carb. The carb has a spacer on it that came with the rebuild kit, and I checked before putting it back together that it wasn't blocking this port.

As far as I know the brake booster and master cylinder are original.

I didn't replace the drums or shoes. They weren't grooved, and everything seemed in order. It doesn't shake, make noise or lockup the rear.

The booster pushrod is aligned properly. All linkages are through the original holes and are inline for best angle.