Air Brakes--- how to use

[speedman42]

I am very new to this, and I am learning how to use (Operate) my first vehicle with air brakes. Can you tell me the proper way to use these. They feel totally different than standard brakes. I had the Brakes and all of the undercarrige inspected. All is good so I just need to learn the proper way to use the air brakes. Any Pointers would be greatly appreciated.

[Steve N Sal]

That's a very good question to ask. A lot of people take them for granted. I'm sure there are some threads that you can either search on the forum or you could "google" air brake instructions. It's a very important thing to know the sytem and how it operates. I can't give any advice on the subject as I have a gas coach with hydraulic brakes. Good Luck.

[Dogpatch]

I have taken the air brake course and highly recommend anyone who will be buying a coach with air brakes to take the course. It's usually put on by truck training companies. Anyone can push a brake pedal, but understanding how they work recognizing the problems and what to do when air loss occurs is important information especially when driving 16 tons of Motorhome down a steep grade. In Canada, it's the law that you have an air endorsement to operate any vehicle with air brakes.

[speed racer]

In the beginning give yourself a lot of room to stop and drive very carfully and give yourself plenty of room in front of you. They are a lot differant but after a while you will get use to the feel and learn how hard and how fast to apply the brakes. It's a matter of how it feels

[pivotdoc]

Basically you just have to learn to "squeeze" the pedal to apply braking - if you jump on it like hydraulic brakes you'll be picking yourself off the windshield...........it'll come natural after a little practice. I have found the engine braking to be very effective to control speed in hills and also use it when approaching turns/stop from highway speeds.......... JB

[johnny101]

Just a few things to be aware of if you are new to air brakes your low air warning device should come on no lower than 55 psi the governor cut in to start building up air pressure is not less than 85 psi and the governor cut out pressure can be no higher than 130 psi I hope this helps

[Mac99]

Use them like any other brake, but do not pump them.
Keep your foot on the pedal, vary the pressure you apply
based on the situation, and remove your foot when you
are done braking.

[RV735]

I would suggest that you go to your state Motor Vehicle Office and obtain the drivers manual for a CDL B license with Air brake endorsement. There is all the driving techniques, Air brake tests before driving each time and safety information for highway driving.


Safe travels and THE JOY IS IN THE RIDE

[jetfromtn]

The thing I had to learn is, the air holds the brakes open and when you apply the brake pedal it releases the air pressure and the spring closes the brake against the drum. Same thing happens when you apply the emergency brake, you release the air and the brakes close. It is completely opposite from what most of us are used to and there is a learning curve.

Jim Thompson
2007 Coachmen Pathfinder 384 TS
2007 HHR

[CaptBill]

There are a few things to remember when driving a rig with air brakes. As previosly said, it won't take a lot of pedal pressure to bring the coach to a stop, and you'll get the feel of that pretty quickly. But you need to remember that if air pressure is suddenly lost (very rare), the park brake will automatically be set, which is not very effective at stopping a moving coach.

*** and ***

If you are driving and the low air alarm goes off (55 psi), you have only 3 presses of the brake for a controlled stop, as each time you release the pedal, you are of course releasing air pressure. So do not pump the brakes in this case.

Most diesel powered motorhomes have an exhaust brake (PAC brake), which can be turned on to use the engine exhaust to effectively slow the coach, to nearly a stop. Learn how to use it, and you won't be on the brake pedal as often. The other "brake" that will be of great value it the transmission shift pad. If you are descending a grade, you should use whatever gear you transmission was in going up the grade, use to go down the other side. You can manually select the gear, and the transmission will only go the that gear if it would not harm (overspeed) the trans or engine.

You can do on-line air brake training, and also attend one of the chassis manufacturer seminars at the bigger rally's. Thanks for asking the question.

[Hooligan]

Good Airbrake manual: http://www.mpi.mb.ca/PDFs/AirBrakeMa...alComplete.pdf

Use of air brakes and exhaust brake is very effective. Your MH will also have ABS, you want to avoid pumping your brakes as it will deplete your air supply faster than the compressor can build it up. When your air pressure gets too low the brakes apply and cannot be released until air builds back..
On a steep downgrade use the engine brake and if speed builds up, apply the foot brake firmly to snub your speed below the max speed you want then get off the air brakes and let them cool and the air build up until your speed builds and you need to snub again. The engine brake will still help control your speed.

[Dwight]

Originally Posted by jetfromtn

The thing I had to learn is, the air holds the brakes open and when you apply the brake pedal it releases the air pressure and the spring closes the brake against the drum. Same thing happens when you apply the emergency brake, you release the air and the brakes close. It is completely opposite from what most of us are used to and there is a learning curve.

Jim Thompson
2007 Coachmen Pathfinder 384 TS
2007 HHR

NO! NO! NO! The brakes are applied by the amount of air that is applied to the empty air brake chamber located at each front wheel & each dual & single rear wheel. The amount of air is controlled by how far your foot pushes down on the brake pedal.

You are correct about the parking brake chambers located on the rear axle only. A coil spring applies the parking brake & air pressure is used to compresses the spring to release the parking brakes.
Dwight

[Cooperhawk]

When I was sixteen I remember my late Father patiently teaching me how to drive tractor trailers. I miss him a lot. I drove semis for him for many years after that. Yep, that's right, he started me off at sixteen. Wouldn't get away with that today.

First he said that whenever you apply brakes you have wasted energy. Your focus should be well in front of the rig you are driving. You cannot fixate on the car right in front of you as it takes a lot longer to stop a heavy rig than it does a car. Plan ahead. Anticipate what's going to happen. Act in advance.

Whenever you can, let the rig slow down on its own rather than use the air brakes. Use the engine brake whenever you have time. It will save on brake pads.

Whenever you can let the rig gather speed on a decline if there is a hill to be climbed to dissipate the energy. Think in terms of energy but don't let the speed get excessive.

If you ride your brakes all the way down a long hill, the brakes will overheat and can possibly be damaged. If you continuously feather, (or apply and release the brakes), you will deplete your air supply and soon be in trouble.

On long steep grades, gear down. Most steep grades will have signs advising trucks to gear down, follow the advice.

Always think of speed as energy and brakes as energy depleaters. Manage your energy.

[sswilson]

As you can see by the responses and some differing opinions, it would be wise to take a course to learn how they work, pre-trip testing, and system maintenance. I had to do it to get an endorsement on my license, but much better that I understood how and why they work. It is not rocket science!

Good luck