First time driving with air brakes, operation question.

[PeterH]

Hello. I am shopping for my first Class A and I drove a 40' DP for the very first time yesterday. As a first experience with such a big rig, it was reassuring because I had no trouble at all.

However, I do want to ask about the braking system. This rig is a 1999 Country Coach Magna with a 385 Cat motor. Acceleration was what I expected, but stopping wasn't. Well, I'm not really sure about that... as I said, this was my first time operating a rig with air brakes. The sales person said it was operating normally. However, I know they are anxious to move this used Class A.

Is it normal to have to fully depress the brake pedal to activate the brakes enough to bring the rig to a stop? Should you be able to apply the brakes enough to cause more dramatic deceleration? As it worked for me, I had to depress the brake fully to bring the rig to a stop. I didn't really notice much slowing until I had the pedal almost to the floor.

I plan to find another, newer rig to take for a test drive but till then, I am hoping someone can offer some help with this question.

 

[Back2PA]

Is it normal to have to fully depress the brake pedal to activate the brakes enough to bring the rig to a stop? Should you be able to apply the brakes enough to cause more dramatic deceleration? As it worked for me, I had to depress the brake fully to bring the rig to a stop. I didn't really notice much slowing until I had the pedal almost to the floor.

Absolutely not normal. With moderate brake input I can get significant braking. I am certain I could chirp or even smoke the tires with full braking, as it should be. I would look elsewhere

 

[PeterH]

Thank you for your reply. That is what I was afraid of.

Wondering if the rig just needs a serious brake rebuild or what else might be the problem. I agree that this rig is probably not for me. I can't get a straight answer from the dealer about how many owners it had or how it was used. Although they've had the rig in their hands for a couple of months, they've done nothing to it so I suspect they just want to flip it with as little investment as possible. I'm just not sure if I want to take on the responsibility for all the repairs or maintenance needed.

Thanks,
Pete

 

[Back2PA]

There are plenty of fish in the sea, I'd move on to the next one.
Live long and prosper.

 

[Roy M]

Either the brakes are worn out or not adjusted properly. It shouldn't take full pedal to stop that coach NOW. That is a 20 year old unit, I would keep looking.

 

[Utclmjmpr]

I doubt you will "chirp the tires" with a 40K rig with an ABS system,, What WILL effect braking to a large degree is oil or grease on the brake shoes..( Caused by inner wheel seal leaks) You can roll under the rig and look for oil on the inside of the tires and backing plates.>>>Dan

 

[kdbgoat]

I would recommend that anyone using air brakes to get the information on CDL air brakes endorsement from their local DMV and learn about them. They're not as simple to use and maintain as a car's brakes.

 

[muskoka guy]

Here are some practice tests from Ontario to get your air endorsement. If you take them all until you get all the answers right, you will have acquired the majority of knowledge you need to know about air brakes. Cheers
http://www.irv2.com/forums/f258/could-you-pass-an-air-brake-test-348054.html

 

[Alfa38User]

Here is the IRL for the same tests without going through multiple steps to get there...

https://www.drivingtest.ca/ontario-air-brake-z-endorsement-knowledge-test-practice/

Here is the handbook that goes with it:

https://www.ontario.ca/document/official-air-brake-handbook

Note that all jurisdictions may not require such endorsements but the knowledge gained is invaluable to owners of vehicles having air brakes.....

 

[timjet]

The brakes on that coach are not working properly. The feel on air brakes is just like your car brakes.

If you buy a coach with air brakes it would be helpful to familiarize yourself with air brake operation. Personally I don't feel an endorsement is necessary but do know that draining the air tanks of water, preform a ABS modulator test and preforming a slack adjustment periodically is necessary. Also you should know how the parking brake system works.

 

[Gary RV_Wizard]

Modern diesel chassis air systems include an air dryer and automatic moisture ejection, so for the most part owners need not worry about draining water from the air tanks.  However, it's still good to be aware of the possibility of moisture in the air, and also to be familiar with the need for periodic replacement of the air dryer desiccant cartridge.

I'm all for a better informed driver, but I suspect most gas-chassis drivers couldn't describe how their hydraulic brakes work or name the top maintenance needs. Yet they largely manage to drive (and stop) OK.  Those who neglect maintenance on their vehicles probably are not going to be change their bad habits merely because they managed to pass a test once.

 

[Chet18013]

Check with your home state DMV. Most states require a special endorsement or non-comerical driver's license for any vehicle over 26,000 GVW and air brakes. Your state DMV should have a CDL license booklet that will explain air brakes and the tests you are supposed to do to check them out.

Your air brake peddle should not need to be pressed almost to the floor. Slight pressure should slow you and hard pressure should apply the brakes just short of locking the wheels - assuming the coach has anti-lock braking. Many air brake systems will self adjust when the brakes are applied when the vehicle is being backed up.

You should learn and know the difference between air and non air brakes to safely drive an air brake vehicle.

 

[muskoka guy]

Having an understanding of how your brakes work is not just  a good idea, it can be life saving. I saw one thread where the person was new to air brakes, and forgot to pull on the spring brakes when parked. They could have ran themselves over or someone else. Also, not being aware that if your low air warning comes on, you had better pull over fast is something anyone driving air brakes should be aware of. The tests are kind of a fun way to learn the basics. They are the same test we have to pass to get our air endorsement here in Ontario.