1979 Chevrolet C70 Conversion to OEM Air Conditioning

[Robert1970C20rstbukt]

You're welcome, we did our best to locate things when I worked at the parts store and that stuck with me. I look up my own parts before I go to the store to avoid unnecessary headaches haha. Seems like that fan would work, the 2" difference in diameter shouldn't hinder the cooling any I would think. The depth that the fan goes into the shroud is important for sure. The height of the 2797 clutch is about 3 5/8" roughly. The bolt spacing for mounting the clutch to the pulley/pump is 2.5".

[Airdirect]

I need to measure the depth to make sure I have room for it. I will take some more measurements and post the results.

Thanks Robert!

[Airdirect]

Shortened the frame back to its original wheelbase (203 in).

[Airdirect]

Been going through the brake system replacing wheel cylinders and hoses. I have also taken the opportunity to strip and prepare to repaint the Dayton hubs. I have new tubeless 11 - 22.5 rims and radial tires ready to be installed. I wanted to keep the original 9.00 - 20 rims, however radial tires for them were almost impossible to find and very expensive. I know in the long run the tubeless is a much better option.

[Airdirect]

Continuing to make progress on the brakes. Front brakes, master cylinder, and hoses are finished. The passenger side rear is ready to have the drum reinstalled and it will be finished.

[Airdirect]

New front brake lines:

[Airdirect]

Can anyone tell me what the sender on the Secondary fuel filter does? It has a single wire going to it. I assume it applies a ground when the pressure reaches a given threshold. I have grounded the terminal and do not get any light showing on the dash. I have reviewed the wire schematics and do not find any information about it.

[gmtech68]

On our 8V71 's at work it is connected to a circuit that allows the engine to stay running. No fuel pressure; shuts off. However those engines have a Woodward hydraulic governor. Yours does not. May also be used as a "run" circuit to send power to various things to signal the engine is running. It has been a while since I've had to mess with that engine. Pretty reliable.

[Airdirect]

Finishing up the last brake. Here is a picture showing my sons Micah and Noah learning how to reinstall the rear brake shoes. They were fascinated with how the brake spring installation tool worked. In this picture they are installing the lock rings on the brake shoe retainer castle nut.

[jumpsoffrock]

Can you post a picture and hopefully a part number of the brake spring tool you used?

When disassembling my C50 brakes I used big ass sheetmetal pliers but it was not fun.
Thank you.

[Airdirect]

Originally Posted by jumpsoffrock

Can you post a picture and hopefully a part number of the brake spring tool you used?

When disassembling my C50 brakes I used big ass sheetmetal pliers but it was not fun.
Thank you.

Here is a picture. It makes spring removal and installation a breeze. No effort required.

[Airdirect]

Finished brakes, installed new rear transmission seal and parking brake shoes. Installed new front shocks, my sons Noah and Micah stripped and repainted the front and rear hubs and clamps. Installed new tubeless rims and tires (11.00R 22.5 radials) Next step is to acquire a bed and we will be ready to haul.

[Airdirect]

Drove the truck to town and got it inspected and licensed. The truck rides terrible with the new tires. The air pressure is 85 psi. The old bias ply tires rode much smoother. The left rear duels wobble just a bit, will have to loosen and re tighten them to see if I can correct. I sure hope the bed weight will smooth things out! Any ideas?

[Robert1970C20rstbukt]

Best thing to do is jack up the front/rear and spin the tires by hand and check for run-out. We had that happen on our old '79 Ford L8000 water truck at the fire department. The front wheels were actually worse, when I looked out the driver's door while rolling I could see the tire/wheel wobbling in and out. Local tire shop apparently never worked with Dayton wheels before. I'm actually going to look at a 1989 C70 cab and chassis next weekend if they don't sell it by then. Has a 366 and a 5+2, has the same wheels but it has 10.00-20 tires.

[Airdirect]

Thanks Robert, I will jack it up and check the run out. Hopefully that will fix the problem. I hope it is not a bad tire. I still need to get the A/C fan clutch installed. I am sure it will reduce load on the engine and noise. The current fan is fixed and very noisy. With a Detroit Diesel cooling is not much of a problem. I cannot imagine why GM did not make the clutch standard on this model. Thanks for all your input!

[Airdirect]

I am having trouble with my new Accuride de-mountable rims. The part of the rim that clamps to the wheel runs true. However the outer rim wobbles. It appears that when the welded the clamp ring to the wheel they did not have it square. Anyone else had problems with Accuride rims?

[DT3Ton]

Thanks for documenting this so well.

Were the AC donor parts from a pickup or MDT? I would like to add air to my crew cab.

[gmtech68]

Find an experienced tire guy. It is part art, part skill to tighten clamp nuts so the wheel runs true.

[Airdirect]

The parts were from both a C65 and 70's pickup. The evaporator and heater core are all the same. The parts that are unique to the 2 ton are the vent distribution in the dash and the mode selector control (no bi-level mode on the truck). I believe that a pickup unit would work, you would just have to use hose instead of the molded plastic parts to distribute the air to the drivers side of the dash. I am not totally sure as I was able to rob those parts from the C65. I know the heater floor distribution is different. I reinstalled my original heater floor distribution unit and it mated up with the pickup evaporator housing. The pickup condenser is very similar and can be made to work. The lines on it are aluminum where the C65 used steel. Hope this helps.

David

[Airdirect]

Originally Posted by gmtech68

Find an experienced tire guy. It is part art, part skill to tighten clamp nuts so the wheel runs true.

Thanks!

[Airdirect]

More progress. I am purchasing a Jerr-Dan rollback bed off a wrecked GMC/Chevy Medium Duty truck. The bed has been removed and is being prepped for installation. The bed was purchased from Jon Wickham and Associates, a Danco Products dealer in the Dallas area (jonwickham.com).

[Airdirect]

Picture taken by Jon Wickham & Associates of the truck awaiting bed installation.

https://www.facebook.com/jonwickhama...ciates/photos/

[jumpsoffrock]

What is the bed Weight? I am so envious..lol
Man that's gonna be one sick truck.

[Airdirect]

I weighed the truck, without the bed it was 9,600 lbs. I do not know what the bed weighs.

[Airdirect]

PTO is installed, awaiting hydraulic pump which will be bolted to the flange.