"Papa Smurf" - 1966 GMC 1500 Custom

[LordNatedawg]

I don't like to jump the gun, but I think I solved the problem. I installed a new master cylinder. An OEM ACDelco meant for a 1979 GMC C2500 HD. Plumbed some new lines to the proportioning valve, bench bled the master, and then installed it. I also installed larger disc brake calipers because the old ones I had were meant for the light duty C25. Lots of air in my brake system, but the pedal is significantly stiffer and only sinks with some constant, heavy pressure. Quickly stomping the pedal makes it feel rock hard. I think once I get everything bled, I should have a solid brake pedal.

Really don't want to jump the gun or jinx myself, but I'm feeling good about this.
A 1/8" increase in bore size doesn't seem like much. But lets assume that the fluid is moving through a cylinder 8 inches long. A 1-1/8" bore and 8" stroke would push about 7.95 cubic inches of fluid. A 1-1/4" bore and 8" stroke would push 9.81 cubic inches of fluid. Now that's not exactly how master cylinders work, but it proves a concept. The volume adds up over distance.

[James]

Are the brake lines copper plated? From what I been told solid copper brake lines is a no-no and prone to failure. Correct me if I'm wrong.

[LordNatedawg]

Originally Posted by James

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Are the brake lines copper plated? From what I been told solid copper brake lines is a no-no and prone to failure. Correct me if I'm wrong.

They are the NiCopp brake lines. An alloy of primarily nickel and copper, as well as some manganese and iron. They were recommended to my by someone who makes custom brake lines for a living. They have the strength of steel lines, but they bend smooth as butter.

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[LordNatedawg]

Finally got my truck to the driveway. The brakes work great! They're actually too good. When I pushed the clutch in, the truck would slowly stop before I touched the brakes. Couldn't get it started in second gear, had to use the granny gear to get it rolling. It also didn't roll back when it was on the sloped part of my driveway. I probably adjusted my pushrod in too far, or I need to back off my drums a bit. I'm just glad I have solid brakes all around. Next task is to obviously adjust my brakes so they don't drag, check and change all the fluids, and then get this thing sent off for an alignment and new tires.

What honestly surprises me is that, after two years of sitting, there wasn't a single wet spot in the gravel. That either means I have no leaks, or the fluids that might be leaking are completely empty. "If she ain't leaking oil, then she's out of oil."

[LordNatedawg]

Small update. Brakes are still locked up because I've been busy with other vehicles. You can see those in the other build thread. That thread is not yet up to date though...because I've been busy.

Today though, I decided to retackle my leaky radiator. Original solder joint did not hold so I tried again. After 4 failed attempts, I finally got it sealed up. I've never done any plumbing soldering, only electrical soldering. It seems that the trick with plumbing solder is to clean everything with muriatic acid, heat the area, clean it more, then add flux, heat, flux, heat, flux, heat, solder. Follow those steps and you should get a clean solder joint. I'm not too happy with how globby it looks, but it seals and is adhered to the radiator, and that's what counts. I might cover it with some JB weld and then sand it smooth. Kinda like bondo.

I should have some spare time this weekend to get the timing sorted on my engine. Needed the radiator sealed so it didn't spray hot coolant on me while I was working. The timing seems way off. Hard start when it's cold, runs okay hot but it seems like it's running rich.

Also I noticed that all of the fittings on my 1/4" brake line are weeping brake fluid. Not leaking, just weeping. The master cylinder is not missing any noticeable amount of fluid, but all of the fittings are wet and some of them formed droplets. I probably need to go through and loosen each fitting then tighten it back down again. Repeat 4 or 5 times to form the flare to the flare nut. All of my 3/16" flares are fine, so I'm guessing it's just an issue of the flares not being formed properly. Again, it's not a bad leak. The reservoir is still full and no drops have hit the ground.