1975 GMC K25 Sierra Grande

[jon75]

Well folks, the gentleman that I bought this truck from said that I should start a build thread. He said even if no one looks at it, I can at least go back and see my progress. I guess I will do that. Here she is in all her "glory".

It is a 1975 GMC K25 Sierra Grande with HD brakes and suspension. It has an LS9 350 with the Muncie SM465 transmission and NP208???? transfer case. It has a Dana 60 front and 14 bolt GM corporate FF rear axle. Apparently, in 1989, the owner at the time put on this 1986 Chevrolet box because of an accident in the side and wanted a box with dual tanks. The passenger side tank was not hooked up at all, and had a filler tube stuffed up through the hole for the filler neck. The driver side tank was in the back of the truck and is a 16 gallon instead of the correct 20 gallon. It also boasted a manual valve located beneath the driver's seat that looks like it's been there for a long time, but is no where close to factory. The front fenders and hood are aftermarket and it is missing the passenger side fender liner. It came with the unusual Holley 450cfm econo-carb, as the entire engine was stock (except the headers). After getting some fuel to it, I realized the Holley was better served as a paper weight. I threw on an Edelbrock 650 cfm 1406 electric choke with air filter housing. I also put on a new cap and rotor from Accel, Accel 8mm wires and Morosso wire looms to keep the wires off the headers. After these changes, I moved the timing from stock 4 degrees BTDC to 8*. After leaning out the carb a little bit and finding 8* worked best, I rid the engine of any dieseling and it starts immediately.

This past weekend I put on two new front brake calipers and one rear wheel cylinder. Those 3 components were all seized and the one wheel cylinder that was working as bearing grease all over the shoes, so those will have to go soon. I bled the brake system and flushed out all the old fluid. I still have the brake warning light on the dash, so I am assuming the prop valve is failing since I also have a rear lock-up issue as well. I still have yet to source new rear wheel seals and bearings to go with the rear brake job.

My hopes and dreams for it are to get some flat black primer on it to keep the surface rust to a minimum and also to get it to one color. I'm still undecided if I want to keep the factory color maroon or go with a different factory paint. Without further ado, here she is:

[jon75]

ALMOST FORGOT!!!! I purchased this truck via a middle man from the second owner. He had purchased the truck in 1976 with under 2,000 miles on it. The truck now has 123,700 miles and has been sitting in various driveways since 1990 when it was put on non-operational registration. The PO was sooo excited when I told him that I got it running, you could see he missed the truck. Anyways, it's awesome because I don't have to worry about smog stuff (being a '75 in Cali is exempt).

I want to make this thing mechanically sound before I do anything to the body. That means sorting out all the wiring as well as the mechanical issues from a truck sitting for 23 years. And I paid $800 for it.

[Chevymaniac]

Great find and a good deal too for what you got. Sorry to burst your bubble, but the front axle the truck has is a HD dana 44 and not a 60. I can tell by the locking hubs. Still a good axle though and keep the updates rolling with pics. Will like to see what direction you go with the project.

[rgunlock]

Congratulations on your "new" truck, and welcome to the forum. I'll be watching to see how this evolves. Thanks for checking out my build the other day.

[jon75]

More pics of when I picked her up.

[jon75]

Originally Posted by Chevymaniac

Great find and a good deal too for what you got. Sorry to burst your bubble, but the front axle the truck has is a HD dana 44 and not a 60. I can tell by the locking hubs. Still a good axle though and keep the updates rolling with pics. Will like to see what direction you go with the project.

Thank you for the correction on the axle ID. I'm slightly new to this crowd. I trained as a GM factory certified technician back in '07 but they only go back about 10 years!

[jon75]

Just a little update:

Yesterday I tore into the prop shafts to try and figure out a vibration that I was getting at highway speeds. I removed the rear prop shaft and inspected the joints. All of the caps moved freely and the grease wasn't burnt. I also pulled the front shaft (pain in the ASS!!) and inspected the joints. I found the double cardin joints to be borderline at best, but the pivot joint was dry and the grease was burnt. Its the part with the ball socket inside the piece. I ordered the AC Delco replacement part and it should be here tomorrow. The nice thing about this truck is that there is about 1/8" or more of grease on everything so it cleans up really nice...no rust at all!

I FINALLY got someone to order up the AC Delco R44TX plugs for me and got those in. I did not have time to readjust the timing yet, but it sure was nice to get the Autolite plugs out of it. Makes me feel better.

I still have yet to get to the local pick-your-part to investigate what they have there. There is a wonderful salvage yard that specializes in early model trucks and has a ton of stuff for this truck. I would love to get down there but I have to take care of my son during the day and it's a 3 hour round trip.

I also picked up a set of 8-lug GM late model aluminum rims that most of the HD trucks had starting in 04 up to 07. I only paid $120 for them so I'm still on the fence about whether I'm going to use them or sell them. I just couldn't pass up the deal. Plus, if I want to use the stock center caps I would have to change over the lug studs and lug nuts to accommodate the center cap fastening design (not to mention that I would have to cut up the front caps to make room for the hubs).

That's all for now.

[jon75]

Today I tried to put together a constructive day, tying together a bunch of little things that have been bugging me about the truck. I focused on getting together the front driveshaft and fixing some of the gauge issues.

The first thing I did was tear apart the driveshaft and sandblast all the pieces separately with the u-joints out of the shaft and the CV joint. There was a lot of crud built up into the retaining ring slots and the sandblaster made quick work of it. After I had sandblasted all of the parts, I installed 3 new Precision u-joints from the local O'Reilly's and shot a picture before installing it.



After installing the driveshaft I moved on to the gauge cluster. Last night I pulled the cluster and tore it all down to the printed circuit board and shell. I removed all the bulbs and took the bulbs out of the sockets. I then cleaned the bulbs with an alcohol and water solution, then placed two small dabs of dielectric grease on the terminals before reinstalling them back to the sockets. From there, I cleaned the printed circuit board terminals and replaced the bulb sockets. I did find one bulb that was burnt out, so I replaced that one. I removed all of the gauges from the shell and wiped down the interior a mild soap and water solution. For the ammeter and the coolant gauge, I cleaned the contact surfaces and the terminals, coated with a light dab of dielectric grease, and pinched the terminals back to closed. I replaced the gauges and wiped off the faces with the alcohol and water. This did help brighten up the white spaces a bit. After that, I washed down the black retainer ring face and installed that. I really wished I had a replacement plastic lens because this one is shot. It looks like someone sandblasted it.





I also found that the PO had hooked up the oil pressure line to the intake manifold on a vacuum port. Then there was an electric oil pressure sending unit stuck in the oil pressure tap right by the distributor that wasn't doing anything. I tested the gauge with compressed air gun limited to 45 psi on my gun and the gauge read around 42-43 so I am pretty comfortable with its accuracy. I still haven't gotten the coolant gauge or the ammeter to work. In fact, now the ammeter is pointed straight down now instead of straight up like it was. Still doesn't move. I am thinking I probably need a new coolant temp sending unit for the other gauge though. Once I started it up, the coolant gauge didn't move but I'm getting 60+ PSI on the oil pressure gauge.

And finally, my protective gear for sandblasting today made up of stuff I had laying around. Enjoy!

[jon75]

Yikes, size 3 font is a little big. One other thing I did too was to remove the tabs that are on the tailgate that don't jive with the '86 bed that's on the truck. So I drilled and removed the locating tabs at the top of the gate and removed the seized release lever and it shut perfectly snug and lined up. I love it when a plan comes together...

[jon75]

Tailgate work: Once I got the handle off, it was quite a bit of work to get it loose and operational again. I sandblasted it, greased it, worked it, greased it, worked it, etc. I then threw some black primer on to keep the rust away. I still don't have the proper hinge pivots yet, so these pictures are the gate lining up with mismatched hinges. Enjoy.

[jon75]

I also removed the bent up front bumper support bracket from the driver's side. I understand that because it was bent to the point of cracking, that the metal has lost it's integrity. I'm okay with that for now and may replace it in the future. But I had some time and a welder, so I made it work for now. I placed it in my bench vise and brought it back as close to straight as I could. I then placed some relief cuts in the metal where it was cracked with a cutoff wheel and brought it back to straight. I took the picture right after welding the bottom side. I also placed another relief cut in the top side so that I could bring the two surfaces parallel. I welded it from both sides on each cut to ensure proper bonding. It bolted up just fine, so I'm happy with it.

[manimal]

Nice find!

[jon75]

Well, I guess it's official....I'm writing to myself on this thread.

Today I installed a new door jamb switch that I got from O'Reilly's, after diagnosing the problem last night. The part was made by BWD and I do NOT recommend this brand. I ended up having to add a washer to the switch because the threads on the new unit didn't go close enough to the head.

After getting some gas tank straps at the pick-your-part yesterday, I wanted to put the 16 gallon tank up under the truck so that I don't have to keep moving it from the passenger seat to the bed, bed to passenger seat. I quickly found that the mounts don't line up against the long bed frame....although I did luck out and found one bolt hole in the frame to mount the front strap to. Keep in mind here that I am only STORING the tank there. All of the holes in the tank are plugged, there is no filler hooked up to the tank and no sending unit installed or hoses.



I then moved on to my attempt to get the coolant gauge to work. I ordered an AC Delco gauge sending unit from Amazon and put that in the block. I was happy to see the gauge move once the engine was started....but then normal operating temperature was right at the "H"....I'm thinking either the gauge is off or the needle needs to be adjusted (if possible). Who knows how many times that thing has been messed with.

After that, I moved on to the dome light not working. After replacing the door jamb switch, I saw there was a light under the dash that I didn't know about. That was a nice surprise. I quickly found that the orange and white wires supplying power and ground to the dome light, that run along the driver door sill, were corroded through. So I picked up a section of that from a donor truck at pick-your-part, soldered it in, wrapped it in heat shrink tubing, and got a new L90 bulb. Works like a charm.

[jon75]

updated pics

[rgunlock]

Looks like you're knocking out your todo list at a pretty steady rate. And moving toward a single color at the same time! Keep up the good work.

[jon75]

Thanks for the encouraging words! I'm trying to just do a little at a time. And yes, those door panels were over-sprayed with white paint from the PO. Classic.

[rgunlock]

Hard to tell in the pictures, but the door panels look to be in pretty good shape. If the plastic isn't getting too crumbly you can paint them and they should look pretty nice.

[jon75]

Nah, the top sill of the door panels are chipping. I am gong to have to work hard to save the wood grain panels.

I actually just got back from my first sewing class with my new machine that I hope to make seat covers with.

[jon75]

This weekend I got a bunch of little things done. I also realized I'm not the best at taking pictures beforehand, making the after pictures seem obsolete. Saturday I focused on trying to get the inside of the truck cleaned up a bit so it didn't look like a barn floor. I picked up all the loose bolts and screws from the interior and put them into a container, and sorted out the parts that are still left to put on the truck. The parts that could fit, went behind the seat, and the rest are in a small box in the front.

One of the cool things that I like about this truck are the floor mats it came with. I'm not really sure if these are rare or if they still sell them by the hundreds, but I dig them. I sprayed them down, washed them up and they look nice (they actually look nicer dry_).



Then today my wife and I went down to Harbor Freight and picked up a nice media blasting cabinet for $100 (on sale from $160 down to $120 and add a 20% off coupon). I love it already. I had a coil air hose laying around and some extra fittings, so I was able to hook up a permanent in-cabinet coil hose to my blasting gun to make it more maneuverable. It works like a charm.

Then, after sandblasting one of our kitchen cupboard doors for my wife to see, I dug into a few electrical issues I wanted to address. First one was to see if the two ancient 4" speakers in the dashboard actually work. Shockingly, the actually did work. Since they did, I figured I would see if the Sears and Robuk stereo that came with the truck worked or not. No surprise, it made noise, but not well. So I scrapped it.

After that I moved on to hooking up the electric choke on the Edelbrock. I live in Southern California so I don't really need it, but I'm Type A and wanted it hooked up. I ran the electrical wire across the firewall through the conduit and through to the fuse block using yellow 16 ga wire. I attached it to fused accessory power and it worked great. I just have to adjust the choke later.

And finally, my last order of business was trying to get the ammeter to work. I picked up a voltmeter at the junk yard last week, but I really wanted the original gauge in there. Mine was facing straight down and never moved so I thought it was toast. After figuring out that the voltmeter gauge would have been a ton more work to get it work correctly, I figured I would give the ammeter one more shot. I spun it back up to 12 o'clock and turned the key on. Voila!! It worked! I love easy fixes.

With all the extra time, I pulled the gauge cover plastic off and decided to try a headlight restoration kit on the scratches and fogging. I think it turned out pretty well. The fogging isn't completely gone, but all the scratches are gone and the fogging has been significantly reduced. Check it out...

Right side of the lens is cleaned, left is uncleaned.

And a couple of pictures installed...

[jon75]

Yesterday I sold a futon on Craigslist and offered to deliver it to the buyer's house for gas money. The 12 mile trip went great except my arms were so tired from working the steering wheel back and forth from the free play that I was exhausted! I talked to the wife about it, and she agreed...time to fix that next.

So off I went today to the local O'Reilly's (I have a business account there) and ordered up a steering gearbox. Cost to me was $128 +tax. I went home and starting pulling the lines and the box. After seeing the fluid come out and hearing my pump having a little bit of noise, I think my next purchase will be the power steering pump. My steering fluid looked like dirty royal purple oil with grease mixed in. It was pretty bad. Here is the box coming out...



And I would have taken a photo of the new box but it was shiny and black, so use your imagination. I did find this interesting though, some blue paint on the pitman arm as I was sandblasting it...



After adding fluid back in and bleeding the system, I took the truck for a ride. What a feeling!! The steering feels almost as tight as my G37! Now all I have to do is center the steering wheel and I'll be done with that. I will leave you with this sweet looking Jimmy (driver) that I would love to have one of someday.

[rgunlock]

Sounds like you had another productive weekend! I didn't get to drive my truck enough before tearing it down to know what works and what wont. I hoped for the best and just cleaned and painted my steering gear box. Guess I'll find out in a couple of years (when I finally get to drive it again) whether that was a waste of effort or not

[jon75]

Originally Posted by rgunlock

Sounds like you had another productive weekend! I didn't get to drive my truck enough before tearing it down to know what works and what wont. I hoped for the best and just cleaned and painted my steering gear box. Guess I'll find out in a couple of years (when I finally get to drive it again) whether that was a waste of effort or not

Being that we are in a small condo inside an association, I can't afford to have this thing down for very long at all. Overnight would be about the maximum. Driving it and working out all the kinks is necessary and it's been working for me. To tell you the truth, I probably would have done it your way if I had the space you do. One day.... Thanks for stopping in rgunlock!

[jon75]

Just when you think everything is starting to come together oddly well....


That's fine, local O'Reilly's has a replacement for $22 my cost and is aluminum. It will give me a reason to redo the heater hoses and get inside the box to check out what's going on.

[jon75]

I couldn't resist getting down to pick-your-part today, so I had my mother-in-law watch the future gearhead and I was off. I just wanted to see what was in this yard, as I had already peeked at the other. They didn't have too much that I could use there. I found an '80 base model that had body panels left, that was about it. I did find one '77 camper special that offered up a bunch of "okay" parts. Like if you had a nice truck and just really needed that one hard to find piece, that would have been a good donor. I did snag the washer fluid bottle off of it. It had the complete factory a/c system still in tact but I don't have money for that right now and it's not a priority. As I walked down the aisles, I saw a few late 80's k5's, a few late 80's suburbans, not much else. But I remembered that, as I came in, this guy pointed out this truck that had been sitting off to the side. He told me it had a good Edelbrock carb on it, if I could get it off. This is the truck he was talking about....

I looked at him and I said, "okay, thanks" and walked away. But after walking the entire yard looking for sport bumper brackets and a license plate bracket for my truck, I said screw it. I figured if I found a nice enough bumper of any kind, I would grab it. I didn't find one single bumper that was good. They were all bent or rusted. So as I was walking out, I walked over to this truck to see if there were ANY usable parts on it. And wouldn't ya know, the bumper and trailer hitch were pretty much the only good parts on the whole truck.

It was kind of a bummer too. It was probably a good running truck, 4x4 1/2 ton with dual tanks, cloth interior, had the clock gauge, intake, carb, headers, flowmasters, h-pipe, American Racing wheels with 35" all terrain tires that looked just about brand new.

So I grabbed the bumper, threw it sideways into my G37, and cruised home to throw it on.

[Willowrun]

Good to see you bringing the GMC back to life. Keep the updates coming.
Posted via Mobile Device