New to 2 ton

[74CustomK20]

Hello all, this is my first big truck, and am having some issues I haven't had on my k20's. Brakes are inop, wiring is worse than anything I've ever seen, the rear is stuck in low range, and the dump bed is leaking like a siv.

The bed works, so I can keep adding oil as needed and figure it out.

Is there anything special I need to know about these brakes? It's hydraulic, has a master cylinder...

The wiring is totally different than my k20. The k20 has a square block that the wires all pass through where the cab wiring meets the chassis and engine wiring, which I guess I'm used to. This c70 has a wide buss bar almost and it's a CLUSTER to say the least. My main question I guess is can I take a wiring harness from a half ton or equivalent truck and make that work on this 2 ton? If so that would be sooo much easier. If not, what or where can I find a wiring schematic? Is there anything specifically different between them?

Anything I need to know about these big heavy behemoths lol?

[74CustomK20]

Little update, got a new Edelbrock 1406. Between that and the new plugs it runs 100x better. Starting to tackle the brakes, and am curious where do I start? There's no booster on the firewall, but there is a huge canister under the driver side floorboard, anyone help me understand what this is, and how these brakes work?

[semn49]

Here's a thread I started. May be a little help?

http://67-72chevytrucks.com/vboard/s...d.php?t=811256

[rkn463]

For your wiring problems, what is the issue? Is it in cab (radio, heater, etc.) or outside of cab (lights, starter, etc.) problems?

The junction block under the hood is awesome when adding trailer wiring, additional lights or whatever you can dream up to add to an existing circuit.

The in-cab wiring is almost identical to the pickups with the addition of a bank of extra warning lights above the instruments.

My recommendation is to just find where it has been hacked and replace wire runs as needed using solder and heat shrink tubing. replacing a complete harness is quite a chore even if you have a direct swap.

For your brake problems I'll let others jump in as I've had no practical experience with the under cab systems. I have a vague understanding of how they are set up but never understood why they thought adding that much complexity to the system was a good idea.

I can tell you that from the under cab master cylinder to the wheels they are just regular old brakes.

[rkn463]

If the junction block under your hood doesn't still have it this is pretty handy. As far as I know they kept the wire locations pretty much the same over the years.