Old Chevy C60 with Air brakes... mystery lever

[danielm]

I just picked up a 69 C60 dump truck to move some dirt around the ranch. There's a lever on the left side of the dash labled "Truck Tractor Protection". It has two positions, left labeled "normal" and right "emergency". It leaks air in the normal position but seems to work fine in the emergency position.
On the bottom it says "Not for parking".

Can anyone tell me what this is for?

 

[mitch504]

When it is in "normal" it supplys air to your trailer brakes, when you have no air-braked trailer, it should be in emergency. A 1969 model pre-dates spring parking brakes on trailers, which is why it says "not for parking".

If you are familiar w/ modern trucks, this is the same as the red octagonal trailer brake knob.

 

[danielm]

Thanks Mitch. That makes sense to me now.

This vid help me understand the system much better.

http://www.youtube.com/watch?v=qJa5-_ExsBE&feature=related