Has anyone ever blown a brake line on a downhill?

Hi folks! My old login wouldn't work so I signed on as HighwayMan101.
I'd like to share the time I blew a brake line going down hill to a red light with a car in front of me.

I had not long left the quarry where I got loaded with 20.36 tons of GAB.
The light ahead suddenly changed to red and I hit the Jakes and got on the brake hard and was not delighted that the car bowed up and stopped instead of racing the yellow light like normal. Still braking hard I suddenly heard this loud POP!!!!
My low air horn came on immediately as the Primary air went strait to zero. What I learned that day was something about - Tank Protection Testing.

Now I did not wish to do Tank Protection testing in this fasion but there I was right in the middle of it. I had never actually heard of Tank Protection Testing at this point.

I stay farther back than most but I was gonna hit the car so checked my right mirror and the turn lane was clear so I ducked into it and got stopped a little past the car and I don't think they ever knew that I was in peril.

The cool thing is the secondary tank kept its air and though I didn't have full stopping power I had some.
With a blown service brake line on the left front tandem the other rear brakes could not get enough air to work at all so that left me with only the front. Its hard to stop 20.36 Tons in a dump truck with front brakes alone on a down hill but that's what I had just done. Thanks to someone who thought of Tank Protection!

Its a good idea to do Tank Protection testing regularly and is quite fun especially when you realize how unhandy and dangerous it could be to lose all the air at once. Of course at 20 to 40 PSI the parking brake will come on if you lose both tanks but then your stuck wherever you are without at least one tank.
The idea is that one tank stays to get you out of the road and into a safe parking place.

Here is a very nice article on doing that testing as well as all the other stuff.
Be safe and keep it between the white lines!
https://www.bendixvrc.com/itemdisplay.asp?documentid=7270

Oh and by the way I got a brand new Bendix AD-IS dryer for the dump truck I drive now last Thursday. Its an 07 KW T800 and the 1st thing I wanted to test was the Tank Protection. Guess what.....it failed! I couldn't believe it.
I could drain any one of the 3 tanks on the truck and all tanks drained equally down to zero.

It turns out there was a DC-4 double check valve between the Primary and Secondary tanks that was stuck in the middle. Its job is to cut off the leaking tank from the system to avoid draining all tanks. This system fills the Primary tank first to 104 PSI and then starts filling the Secondary. Now I know that when it started filling both tanks at the same time a couple months ago that the valve had been stuck then and I was without Tank Protection for 2 months.

 

Me too and thank you. I know another guy who blew a brake line and wound up with his rig inside a building that had a 1 floor level drop down all open lobby. He wound up inside the lobby. He came in on level 2 but wound up on level 1.

 

I have thought many times that I should have pulled the park brake out. I think that should actually be taught in the CDL training if its not already.

 

When you say can are you talking about the air tanks themselves?
Brakes are very important. Back in the day without slack adjusters it was easy to get the brakes out of adjustment and blow through a red light grossing 80.
When that happened I pulled over right then and there and adjusted my brakes. I learned to watch out for that sort of stuff after that.