air brakes on a downgrade

elton10 · Jan 4, 2006

Im new to AB and Ive gotten two very different lessons on using brakes on a long downgrade. The DOT exam study guide says to apply the brakes until your speed drops to 5 mph below what you consider(or what is posted as) safe speed. Then ease off until you are again just easing over "safe" speed and reapply until 5 mph below..etc.
Another instruction manual I saw said dont ease brakes on and off..just put them on enough to keep the truck at or near safe speed with LIGHT steady pedal.
Any pros or cons from my more experienced forum posters?
It seems to me one way would tend to use up air reserve; the other overheat the brakes.
HELP!!!
:7

Tennesseahawk · Jan 4, 2006

Easiest way is to start in a lower gear. I put pressure until 5 mph below, then let off. No way I want my brakes to glaze over by holding them down. Air pressure always builds back enough... never had the warning go off on me.

RichM · Jan 5, 2006

I operate the same way as the Hawk. Stay about 5 mph below the limit,let it build up ,then moderate braking to bring it back down.

FireGears · Jan 5, 2006

Hello and Happy New Year.

Several years ago I went to Truck School to upgrade my
CDL-B to a CDL-A. There I learned the "Brake on.. Brake off"
method to maintain the vehicle's speed going downhill
was required for the DOT license test.

My first job driving a T/T was from Reno, NV to the Port
of Oakland and back daily on I-80 over Donner Pass.
My boss taught me the way he wanted his trucks driven.

When going down a long steep hill use the following method...
Right Gear
Right Lane
Right Speed (based on road conditions)
Right Brake Pressure

The "right brake pressure" was to apply 5 to 8 psi of air pressure
to the brakes all the way down the hill. Never, Never, NEVER
exceed 10-psi... just LIGHT steady pressure.
There were brake application pressure gauges on all the rigs.

Well, as a fireman I was concerned about hot brakes. So... the first
time I used this method with 80,000 lbs going down the loooong Eastbound downhill of Donner Pass I stopped at the bottom to check the brakes. There was not a bit of heat on any of the brakes...
I must admit I assumed they would at least be warm... LOL.
But nooooo... they were all normal.

No hot brakes and perfect control down these very steep grades.
Of course, I was too slow for the super-truckers who would
flash past my truck but that's OK. Safety is priceless.!!

I hauled heavy coming and going so good brakes were a concern.
Yet, I never had a problem. Not with control and not with the
boss who had the brakes checked each night... he knew who was
not using "his braking method" based upon brake wear....LOL

Hope this gives you some insight.

Be Safe.!!!!

FireGears

elton10 · Jan 5, 2006

thanks guys. Living here in GA I dont get the mega hills you have out west. When I was going thru Denver on I-70 my co-driver was at the wheel. I like the "right lane.right gear.." rule since I tend to stick to the right lane most of the time anyway..just seem to get in less trouble there in general.

elton10 · Jan 5, 2006

>thanks guys. Living here in GA I dont get the mega hills you
>have out west. When I was going thru Denver on I-70 my
>co-driver was at the wheel. I like the "right lane.right
>gear.." rule since I tend to stick to the right lane most of
>the time anyway..just seem to get in less trouble there in
>general.

Tennesse: not that Monteagle isn't a tricky one....

and the one AB truck I drove didnt have an application gauge..just reserve

Tennesseahawk · Jan 5, 2006

I went down Jellico the other day. So smooth, I don't remember having to use the brakes much. Far cry from the first time I went down in a truck. I was driving for JB, and my trainer was in the bunk. I saw my trailer starting to come around at 80mph. Luckily, the braking I used worked! The mountains around Asheville are alot worse.

elton10 · Jan 5, 2006

>I went down Jellico the other day. So smooth, I don't
>remember having to use the brakes much. Far cry from the
>first time I went down in a truck. I was driving for JB, and
>my trainer was in the bunk. I saw my trailer starting to
>come around at 80mph. Luckily, the braking I used worked!
>The mountains around Asheville are alot worse.

Southbound on I 77 from the NC/VA line isnt a picnic either..even in a 4 wheeler.. My poor wife got to run it in the rain, after dark and with fog.. the girl can DRIVE!! Im trying to convince her we need to team..
We used to live in Tullahoma and a short while in Madisonville

slowhand · Jan 6, 2006

T-Hawk. I'm curious to know what kind of braking you used when you saw that trailer starting to come around. Especially at 80 mph. Happened to me around Toledo,in the snow. Thank God I was able to speed up enough to get her where she belonged!!

Tennesseahawk · Jan 6, 2006

That was more than 10 years ago. But if I remember correctly, I put steady pressure on until it went straight again, then released.

Crazynuff · Jan 7, 2006

The old rule for Right Gear was to use the same gear going down a hill you use to go up it . With the higher torque of newer engines they now say use a lower gear .

ATeam · Jan 8, 2006

Because of the air brake issues mentioned in this thread, it is wise to include a Jake Brake (a/k/a engine brake) if you are spec'ing a new truck. A good engine brake makes it possible to maintain safe speeds downhill without touching the brake pedal, thereby saving your service brakes from overheating in case they are really needed.

Broompilot · Jan 8, 2006

East Coast - West Coast a 5-6% downgrade is still 5-6% on either Coast, look at Fancy Gap, Black Mtn.

I have driven around the U.S. 4 times now and it must all be taken with the same caution.

All of the Posts are correct on the braking methods, I choose even with a installed Jake to pump at the 5mph rule, Jake slows it to much and gives no warning to the drivers behind you that you are actually slowing as the brakes applied shows brake lights.

Maybee I am to considerate but I always want to indicate to other drivers what my intentions are, and appriciate drivers who do the same. Like using four way flashers when backing into a parking spot.

mhoy40 · Jan 11, 2006

the way i was instructed was to do the stab braking or (the on and off).get to 5 below the posted speed limit use a lowerr gear and apply the brake pedal on and off (stab brake)to maintain the prefered speed. this is the way fmcsa says to do it which is the way the instructors will teach u and the liscene testing people will look for along with the down shifting when slowing or stopping.

FlameMerc · Jan 20, 2006

I agree with Ateam and Broompilot. The Jake Brake is a Must on any over the road driving. I use the jake and a lower gear and turn on my four way flashers and enjoy the veiw. Let the jake do the work, save your brakes. Once in a while you will have to stab brake, but not often...Have a Safe and Profitable New Year...Butch