New to board & GMC trucks! Just bought a 72 Sierra Grande

[centuryhousedw]

Hi everybody - I'm new to the forum though I've been avidly reading it for the last few days. I've just bought my first GMC - a 1972 Sierra Grande. I've wanted a late 60s-early 70s Chevy or GMC pickup since I was a teen back in the late 80s. It is pretty beat, but it was the price point that I could afford to start off with ($1800). The truck runs and drives but had a number of problems when I bought it earlier this week. I understand this will be a project, and there are a lot of things that need doing.

I can't afford to do a full restoration, so my goal will be to have a safe, well driving truck, and while not being hung up on 'all original' I would like to keep it / get it reasonably 'original' where possible.

More info below and questions below the pics:









* Transmission wouldn't shift into 3rd gear until around 45 mph, but I just fixed it by replacing a vacuum line that had come loose.
* Power steering was out but is working now once I tightened the belt and added fluid; there is a leak that I'm working to fix.
* Radiator leak which was just a hose clamp that wouldn't tighten.


* Factory AC is not connected, and appears to my uneducated eye to be missing components.
* Heater not working, but once I learn where the heater core is I'll get it figured out.
* Wipers not working; the push/pull switch itself appears to be broken (?)
* Needs a sway bar, some bushings replaced in the front end, and the shocks are ancient.
* Oil leak - most appears to be the power steering leak that blew back; the rest looks like valve cover gasket leaks.


* The only serious rust is just inside the doors, mainly on the driver's side. The rest actually looks pretty good.
* Missing most of the trim, and has the wrong tailgate (Chevrolet instead of GMC).


Now that I've got the transmission working, next is replacing the power steering rubber hose section and hoping that ends the leak. I bought a variety of hose sizes and will be replacing the vacuum and fuel line hoses as they all look dry rotted. Then the fluids and filters.


In addition to this introduction, I'd like to pick your brains on a few things:



1) how do I get the instrument cluster / bezel off? I removed the screws, found a write up on removing the headlight switch, but can't figure out how to remove the wiper switch assembly.



2) What should this hose from the driver's side valve cover go to? I can't find any fitting on the carb or nearby. There is a similar elbow fitting and hose on the passenger side valve cover, and it goes to a fitting on the back/left of the carb.







3) The splines showing on this bit of driveshaft - is that right???





4) I am guessing this is the AC stuff, and I see a lot of cut hoses. Is the heater core back in there too?






5) Best place to get decent condition trim pieces at the best price? Our local wrecking yards seem to not have much of these trucks.

[MARKDTN]

2-that is your PCV valve. It should go to the carburetor. See these diagrams, they should help with routing. Since the engine is black, it is not original. Hard to say what year the carb is, but most small blocks are similar in thar respect.

http://www.autozone.com/repairinfo/r...00c15280083688

3-that appears to me to be too much spline showing. I would expect 2" or less. I can't find an exact spec, but it looks like too much to me.

4-heater hoses and a/c hoses have been cut (probably when they swapped the engine). They can be put back, but who knows what is good or bad in heater core and evaporator. I would fix it, but be prepared for some expense.

Looks like a cool truck to work on. Enjoy!

[centuryhousedw]

Originally Posted by MARKDTN

2-that is your PCV valve. It should go to the carburetor. ... Since the engine is black, it is not original. ...

http://www.autozone.com/repairinfo/r...00c15280083688

There is what appears to be an identical valve & hose on the passenger side valve cover, and it is run to the fitting on the carburetor. Should I just cap this one off?

As to the engine - could the color be because it was rebuilt and painted, rather than swapped? And is there a definitive way to know if it is original or not (serial# somewhere, etc)?

[68350]

Look in front of the passenger head and there is a little 3-4" wide flat spot. There will be a three letter code on there which will determine what the motor is out of. Driveshaft looks to have to many splines showing. I'm guessing the front shaft has been replaced? The heater core is inside the cab. You will need to take off the inner and outer heater boxes to get to it. You may want to hook the heater hoses up first to see if the core is bad or not. The heater hoses are cut coming out of the a/c box on the firewall. The windshield wiper knob just has a little set screw that holds it on. The whole assembly doesn't get removed until dash bezel is out of the way. Hope this helps you some

[68350]

And I'd watch the parts board on here for a full set of trim. Lots of trucks are parted out and used trim should be fairly cheap

[centuryhousedw]

Originally Posted by 68350

Look in front of the passenger head and there is a little 3-4" wide flat spot. There will be a three letter code on there which will determine what the motor is out of. Driveshaft looks to have to many splines showing. I'm guessing the front shaft has been replaced? The heater core is inside the cab. You will need to take off the inner and outer heater boxes to get to it. You may want to hook the heater hoses up first to see if the core is bad or not. The heater hoses are cut coming out of the a/c box on the firewall. The windshield wiper knob just has a little set screw that holds it on. The whole assembly doesn't get removed until dash bezel is out of the way. Hope this helps you some

Thanks, I'll look for the 3-digit engine code when I get home.

I don't know if the driveshaft has been replaced. I have the disadvantage of not having owned a Chevy or GMC before, so this is the first one I've ever looked at. Wish I had another GMC here to compare it to.

Any idea what I should hook those two heater core hoses to? I don't know where they originally went.

The wiper knob is broken and already off, as is the shaft. The trim ring is there on the bezel and I can't seem to unscrew it. I'm trying to get to the wiper switch wiring so I can 1) see if it works at all, and 2) figure out a way to rig a switch there until I can find a replacement (assuming there are any available anywhere).

I need to take the cluster off anyway though, as the oil pressure and temperature gauges don't work either. I'm assuming someone cut the wires or they got pulled out.

Thanks for the help.

[68350]

The wiper switch washer just does just screw off, may need to use a channel lock or something. Replacement switch should be very easy to find. The oil pressure gauge doesn't have a wire, it uses a copper "tube" that runs down by the oil filter. Make sure that it is even there. Temperature guage uses a sensor that screws into the motor, usually by the drivers head. Or it will use a wire that "hooks" onto the sensor on top of the intake. When I get home I'll take a picture of where the heater hoses go, unless someone has one handy already and posts it before. Really the parts you are needing, should all be fairly cheap and readily available. It may not hurt to become a subscribing member ($25 a year, which goes to maintenance for the board), then you can post a want to buy ad on the parts board. Or you will have to wait til the stuff comes up for sale to buy it.

[centuryhousedw]

Great info, thanks for the advice and help!

[68350]

Here's some pictures. As you can see, on my valve covers one hole is for breather, one is for pcv valve, and one oil fill hole. The red wire running to the intake is the wire for the temp guage. The top heater hose coming out of the a/c box goes to the water pump. The bottoms hose out of the a/c box goes to the valve, then to the intake. That valve also has a vacuum line running to it, that is how it operates I believe.

[centuryhousedw]

Today I replaced the power steering hoses as they were hemorrhaging power steering fluid pretty badly. There is still a tiny leak, but it appears to be from the small part at the rear (toward back of car) of the gear box. Any idea what that is called or why it would leak?

ps - I am buying a manual, just don't have it yet. Hopefully that will help with the parts identification in the future.

[68350]

All of the factory service manuals I believe are on PDF. You should be able to use the search box on top of this page and use the 67-72trucks tab, and find them. They will help a ton

[centuryhousedw]

Thanks, I'll check it out.

If I end up replacing the radiator (there is a crack in it) is there something in particular I should look for, or just go for any old replacement? I'm in Texas, and running cool is very important to me.



BTW - primered it today - at least now the truck isn't 13 different colors