68 GMC Project

[mikewoods]

Hi guys, I've been a long time lurker and I just registered after I bought a 68 GMC for a song a few weeks ago.

The truck was an ebay listing that happened to be local and too good of a deal to pass up. I put in my bid and waited it out. Lo and behold, I won!

It was advertised as needing brakes but "running like a top". It has a solid lifter 327 and a 3 speed automatic. Upon start up I immediately noticed that the radiator was leaking from the fins and the power steering box didn't hold fluid at all. Checking in to the brakes, the master cylinder was full, but the truck had a VERY soft pedal. Crawling underneath i saw that the rubber rear brake line wasn't connected to the T block but crimped over (no rear brakes at all)... No leakage out of the front wheel cylinders, but I didn't get a chance to pull the drums off to look before I bought it. Brake parts are cheap, right?

So to recap; it has mismatched wheels, two different sizes of tires and is spray painted orange, doesn't hold coolant, doesn't hold power steering fluid, oh! and I forgot to mention, the front harness was completely hacked/ unplugged...

Here's the truck when I got it home.



Got it in the (ridiculously messy) garage,

[mikewoods]

The first thing to do was get the radiator out and take care of the mess of a front harness.



I ordered two different replacement radiators from Oreilly Auto that didn't fit and were promptly returned.

http://www.oreillyauto.com/site/c/de...yword=radiator

http://www.oreillyauto.com/site/c/de...yword=radiator

I was really bummed that the first one didn't fit as it was very good quality and had a brass tank and copper/brass core.

The second one had plastic tanks and the core was much thinner, but it didn't fit either.

The radiator I ended up with was this one from Advance Auto. It also has plastic tanks, but for the money, even if it only lasts 5 years I'm ok with it.

http://shop.advanceautoparts.com/p/r...161/19920640-P

[mikewoods]

More fun last night! I got the radiator in. Happily, this one fit with only minor modification to the fan shroud. Another trip to the parts store for coolant and I'll be all set.



The old externally regulated alternator was tired, so rather than replace the old 61 amp model, I rewired the front harness to work with an internally regulated alternator and bought a new (reman) 78amp. Still waiting on an alternator belt from RockAuto, then I can get the alternator in and front harness plugged in and see if my wiring skills pan out.


I rebuilt the front passenger side front drum yesterday too. I replaced the wheel cylinder and flex hose while I was at it. I'm glad I took a photo of it before I took it all apart as the driver side was missing some components (probably another reason it was stopping so poorly). Every time I work I drum brakes I am amazed at how much engineering went in to designing such a shi*ty system and understand why disc brakes are the norm now. I will be saving money for a disc brake swap in the near future.



I borrowed a buddies power washer in hopes it would take the orange spray paint off the truck. I'm hoping I can do it without the use of chemicals, but if need be I have some aircraft grade stripper that will come in handy. Hopefully more progress to come tonight.

[duallyjams]

fix all PO and have fun driving it.

[mikewoods]

Hey Guys, I have been moving slow on this project, but my time in the garage is limited to a few hours a night after the kids go to bed.

I finished up rebuilding the drum brakes. Check out what I found when I pulled the rear drums off.



Ha! Nothing! No wonder there was no pedal!

Moving on to the rats nest of wiring under the hood and in the cab,
With the help of a buddy I cleaned up the front harness and engine pigtails. Its amazing what a little bit of time and effort will do! We reran almost everything to get it out of the way and loomed everything that was still visible.



Compare that to the photo above!

You'll notice the Alternator and battery are unplugged. I'm fighting a 0.79 amp draw from the alternator when the key is off. I was thinking it was a short to ground somewhere in the head light/brake light harness since they are about the only things with power when the ignition is off.

I crawled under the dash to diagnose and found this...



Notice the screw and gum wrappers used as fuses. Also note the bare wire on the dome light pigtail. It seems that any wiring the PO did was "twist 'n' wrap with duct tape. Oye. this has all since been remedied as well.

I'm going to continue to chase this key off amp draw. One thing I noticed with digging around yesterday is that the dummy light/turn signal indicator connector is missing, would that cause an open circuit?

[68Gold/white]

Crap,
You have a lot of un-rigging to do!!!
Is that a one wire alternator???

Glad to hear your plans for disc brakes in future, life is too short. The plain old single piston stock type disc brakes do an excellent job, no need to purchase anything fancy. My 67 and 68 will both have disc when they see the road again. Moser has been advertising stock c-clip replacement axles for $260.00 for the pair. A friend ordered a set for his 67, had them make the lug pattern 4-3/4" (5 lug, of course ). If you or anyone orders these, make sure you have them install new studs, the charge is minimal, and worth it. Tracking down appropriate wheel studs isn't worth the time....

Nice firebird! Do you ever look at the Pontiac website, performanceyears.com ?

[mikewoods]

Thanks man! I'm not sure exactly, I think it's a 3 wire with the voltage sensing wire jumper end back to the battery terminal.

I'll look in to the moser axles, sounds like a good buy.

I'm a sucker for Pontiacs and GMCs. I haven't checked out performance years yet, but I will now!

[duallyjams]

It's amazing the things you find that other people do just amazing.

[Xeen]

Here is something that will solve your hacked up rigged wiring harness problem.
http://www.speedwaymotors.com/Speedw...ness,2352.html
For the money it can't be beat considering it will flat out eliminate any and all issues by replacing the stock harness.
Plus upgrading to spade fuses is a nice bonus.

[mikewoods]

I've found that my draw is coming from the wire that goes back to the generator dummy light by disconnecting the fire wall connector and testing each pin with the battery hooked up. The problem is, my generator dummy light is disconnected, so I need to find out where that wire goes on the other side of the firewall. Hopefully that will solve my problem.

[mikewoods]

I assume this is a ground for something in the dash cluster, but where does this wire go?

[mikewoods]

Tracing this issue (20 Brown wire constant .79 am draw), I pulled the gauge cluster off looking for an obvious issue with the wiring under the dash. I didn't find that, but I did find the printed circuit board was peeling and separating. I know the plastic shouldn't be separating, but these pins aren't where I'm having the issue. Could a short in another area of board cause a short to ground in the alternator dummy light?

[mikewoods]

After more searching, I tried a few more things. With the ignition switch and the instrument panel connectors disconnected, I still have a draw. I think that means there is a short to ground somewhere in one of those connectors. Is that safe to say?

[Xeen]

I really wish I could be of some help here but electrical troubleshooting isn't my strong suit.
If it's messed up I rip it out and install a new kit

[mikewoods]

I agree Brian! It would be much easier to swap in a new kit, but I just don't have the funds to do so right now. I think I have it narrowed down, I'll let you know after I swap ignition switch connectors tonight.

[nlped]

Looks like a handful, but just keep plugging along and you'll have yourself a nice ole truck. I absolutely hate tracking down electrical gremlins...such a PITA, but has to be done.

Love the Firebird too.

Sub'd

[mikewoods]

Its amazing what a few hours with some paint stripper and a power washer will do. I still need to do the doors and grill, but I think it turned out pretty cool.

[gdavis]

Screws and gum wrapper is a recipe for a wire fire. I to am looking to rewire my 68. seams like every time I have enough saved for a new harness I see something I want. Like this week I seen a new steering wheel. had to have it. But keep on keeping on and you will get it done. good luck

[thelonerife]

looks like it was my color. Keep it up

[mikewoods]

Took a more recent picture this weekend. Its finally on the road! Proper wheels and all! Next step is to rebuild the front end, swap in some drop coils in the front and an axle flip kit in the rear.

[GAc10boy]

Good progress!

[alsriv2]

Very nice truck you have there. It's a shame there were so many issues with it, but you handled it all nicely. Its amazing how some people disable and remove required items on brake systems in the name of "repairing" something.

[Mr Chevorlet]

Funny what you find after years of other peoples craftsmanship, but it looks like you getting it repaired, great job.

[mikewoods]

Still working on this truck slowly...

New Carb
Valve covers
Cap, Rotor, Wires, Plugs, Boot covers
Fuel Filter

[gdavis]

Dual line at that, good work george