O.K. I just finished my first week of feeder (CDL) school with UPS. On the 4th day we took a drive up I-70 to the Eisenhower tunnel. I got to drive back. Still sweating. Anyway we were taught not to stab our brakes coming down. FYI no jake brake on this truck. UPS says that stabbing brakes causes them to get hot and when you let off the brakes the oxygen gets in there and can cause a fire. They taught us to very lightly ride our brakes down step grades. We also geared down. My instructor did it on a step grade as we were going up to the Eisenhower tunnel. Got out and smelled the brakes and they were fine. I did it coming back down into Denver and while I didn't smoke the brakes I did get them a little hot and I could smell them. Has anyone heard of this technique? My instructor was fine, because I didn't smoke the brakes. Just wanted me to be a little lighter on the brakes.

 

I was always taught, if your wheels are rolling, you will be fine. it is when they lock up you can/will slide. On downgrades, i was taught the amount of time you are off your brakes, should be longer than when you're on them, if they're not, they will heat up. Also, i try to be nice and easy on and off the brake. Keep them from giving that 'hiss' when you let off the brake. cause everytime they 'hiss', you lose tank pressure. never shift on a downgrade, and go down in a gear or two lower than what you went up in.

you can go down a hill as slow as you want as many times as you want. you can only go down a grade too fast, once.

 

I know its strange, but they want very light pressure on the brakes all the way down. Don't let off until at the bottom of the grade.

 

i just got out of training and as odd as it sounds my finisher said the same thing. i'm still perfecting the technique.. i could smell them as well and i still get that "hiss" once in a while.

 

I find that very interesting, considering that in the CDL manual in WI back in about '96, it stated that steady pressure on the brakes going down hill contributed to cracking of the drums. Very interesting indeed.

 

My Colorado manual says the same thing. The light pressure is very very light. I think its just enough to keep the brake lights on. When I came down I think I was a gear to high and the truck would try to run from me and I needed to apply more pressure. UPS is a huge company, so I'm sure they have more than studied this technique out. Just so different from what I learned and studied in the past.

 

This has been the prescribed method of decending mountain grades for years and years. It is what my eldest brother learned in the late 60's(in a truck with a jake no less), and it is what I learned in the 70's. Light pressure and the proper gear, allows you to do your job, with minimal waste of time.

And here I was thinking that UPS had jakes on their trucks.

You will get the hang od it Brown67...and Elk Mountain isn't all that bad...really. Coming down Eisenhower is a good way to learn to drive!!! Smart idea from UPS. LOL...now...there are a couple grades in Colorado worse than that one, when your in a truck...but they are down south and west of you.

 

Light pressure with or without a jake in the proper gear is the way I was taught as well, back in the mid 80's. I've used this technique ever since and have never smoked the brakes. I've been down every major grade in the country that I know of, never had a problem on any of them.

 

I know. That is what I was originally taught too, but when I started training, it was brought to my attention. First, select the proper gear to descend (without an engine brake it will be a lower gear) then use the brakes only if you must... Allow the truck to get up to the maximum speed, then use the brakes to reduce the speed to about 5 miles below (no more than about 15 seconds worth), then allow it to continue with engine braking. It was called "Modified Stab Braking" in the manual. But, when descending a grade, your main means of braking is to be the engine.

 

UPS jobs are so crappy they need to hire trainees??? I would have assumed they'd have experienced drivers lined up and waiting to get one of those union jobs.

OXYGEN??? ha ha!! That makes no sense! What is between the drum and shoe? Nothing but air. Air will not ignite. Otherwise the next guy to light a cigarette is gonna blow up the planet!

If all we had to do to generate oxygen is make friction (by applying brakes) we could all have oxygen generators on our trucks and have direct oxygen injected engines for greater fuel economy/engine performance.
Dry air contains roughly (by volume) 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.038% carbon dioxide, and trace amounts of other gases. Air also contains a variable amount of water vapor, on average around 1%.

When brakes get hot enough to start things on fire, the metal is glowing cherry red and over 1200°F. The stuff that burns is the oil/grease, seal material and finally the tire if the heat continues to transfer through the entire wheel.