"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.

[LordNatedawg]

Been neglecting this forum. A few months ago I got my engine close to perfect on the timing. It doesn't spit flames and backfire anymore, but it still could use a bit of tuning on the vacuum advance.

I also solved my locked up brakes. First, the parking brake was adjusted too tight by the previous owner. Loosened the cable, pulled the handle 4 clicks, then tightened the cable until the brakes started to drag. After that, I had an issue with a kinked brake line at the proportioning valve. Used my last 6" of brake line to recreate the 4" section; no room for error. After that was solved, I had some preload on the master cylinder. Seeing as my pushrod is already as short as it can go, I had to put 2 washers behind the master cylinder. It solved the issue. Wheels spin freely with engine running and engine off, but the brake pedal doesnt have too much travel before the brakes are applied.

This truck is almost road worthy. It still needs tires and the control arm bushings torqued, but I think I can solve those fairly easily. I got a new torque wrench that should help me get the leverage to get 220lb-ft on the upper bushings. Also, I recently got a job at a tire shop. Might be able to bring the loose wheels to work some day and mount up some new tires on my lunch break.

[LordNatedawg]

Tried to finalize the timing on my engine today. Things were going well until my alternator died. Shortly after that happened, my distributor cap decided to snap off. Oh, and I had to stop a few times to let my engine cool down because it was running at 240 according to my thermal gun.

My truck is dead, but it presents at least two opportunities for upgrades. I'm going to install an HEI distributor and an internally regulated alternator. Additionally, while I have the distributor out of the way I will also install an electric oil pressure sensor. I'm hopeful that sorting out the timing will also help the engine run cooler.

Sucks to take 2 steps forward and 3 steps back, but it'll be good to get this engine running smooth and clean.

I know there is some speculation on whether HEI distributors will fit on a 350 in our trucks, the main concern being firewall clearance. From what I've seen it'll be a tight fit but it will indeed work. I'll let you know otherwise.

Tomorrow I'm making a trip to the parts store. Hopefully I can get my truck back up and running before I have to return to work next week.

[LordNatedawg]

New alternator is installed, HEI distributor fits, and my electric oil pressure sensor just barely fits. Tomorrow I plan on actually wiring these all up. I also installed new spark plugs gapped at .045 for the new HEI distributor. I'll be replacing spark plugs wires as well.

When I pulled my wiring harness today I saw the horrors of 50+ years of custom wiring. The harness is a complete mess. After trimming most of the terminated wires I think I can finally makes sense of what the harness was meant to do.

Once I get everything back together I'll let you all know about part numbers and wiring diagrams.

On an interesting note, whoever installed the last distributor forgot the gasket. So I solved one major oil leak there. They also did not use any sort of sealant on the mechanical oil gauge, so that is a second leak solved (assuming I used enough of the proper sealant). At least I know for certain this gauge won't leak inside the cab. Lol.

[LordNatedawg]

My truck did a very good toaster impression today. Lots of smoke coming out of the air vents.

Long story short, something in the original harness was shorted and melted almost every electrical wire inside the cab. And it only took a few seconds. I saw smoke, I unhooked the battery, everything was burnt and melted.

All the wiring I did is fine. It isn't melted, it didnt even get warm. The only thing I did with wiring was remove/replace the resistor wire, remove the alternator external regulator, and repair wires that were spliced for accessories that no longer exist in my truck. Everything is wired up according to my 65-66 GMC FSM.

I don't even know if my truck runs with the new distributor because I never got the chance to crank it over.

[Prowbar]

Man, just read through your entire thread, ungrateful work it seems like. Fixing the crap produced by the previous owners take a heck of a lot of work. Will be following your thread with interest and I commend you on your ability to just carry on (when you aren't out fixing family vehicles!)

Good luck.

David (also a young guy at 22)