RV Driving Tips
- Written by Gary Lewis
Most commercial vehicles and large diesel housecars use Air Brakes to stop. As part of the Pre-trip inspection test for a CDL, a driver must demonstrate knowledge of how an Air Brake system works and how to check it. Noncommercial Class B applicants are not required to pass this portion of the test, but all Class B Boot Camp Grads will be proficient in the Air Brake Test.
To check an Air Brake system, the driver is expected to perform an in-cab air check or as it is known in California,
A COLA check.
C stands for COMPRESSOR CUT IN: The Governor will cause the air compressor to Cut In and start pumping, when the pressure in the system drops to between 85 – 105 psi, as indicated by the air gauges. When the air gauge needles rise the driver knows the air compressor pump is working.
O stands for COMPRESSOR CUT OUT: The air compressor, shown in the diagram above will pump air until the system is fully charged, 120 – 130 psi, at which time the Governor will cut out the pump and you will hear an air blow off. (Psssh).
L stands for LOW AIR WARNING: All Air Brake equipped vehicles are required by law to have an audible and a light warning system to alert the driver, should air pressure fall to 55 – 75 psi. This is important information for the driver because if the air pressure were to fall below 45 psi, the brakes in the vehicle will immediately be fully applied!
A stands for APPLIED AIR LEAKAGE TEST: The purpose of this test is to ensure the system is secure and has no leaks. With a fully charged air system and the vehicle securely parked, the driver releases the parking brake, turns off the engine, presses and holds the brake pedal to the floor for 1 minute, making sure the system does not lose more than 3 psi. When finished, the driver indicates to the examiner there was no air pressure loss and applies the parking brake.
PRACTICAL BRAKE TEST:
Parking Brake Test, with the parking brake on, put the coach in gear to see if it holds.
Service Brake Test, release all brakes pull coach forward about five feet, apply service brake making sure the coach stops smooth with no pulls in either direction.
Recently while doing the pre-trip on a mobile clinic with a diesel engine I noticed something I have never seen before, an empty DEF fluid gauge. Unfortunately the drivers I was training had no idea what DEF fluid was or why it’s important, hence this explanation.
What is diesel exhaust fluid? DEF, is an elixir that’s necessary to make sure that what exits a diesel vehicle’s tailpipe is as sweet as an Alpine breeze. The DEF fluid gauge is usually beneath the fuel gauge and in this case, shows 0. When full it would show four green bars.
DEF, is a fluid consisting of urea and deionized water in a 1:2 solution. It’s contained in a reservoir separate from the fuel tank and is metered into the engine’s exhaust stream to control certain emissions. Inside the exhaust pipe, the DEF vaporizes and decomposes into ammonia and carbon dioxide. Those two compounds then react with oxygen and detrimental nitrogen oxides inside the vehicle’s selective catalytic reduction (SCR) catalyst. This produces three benign tailpipe gases: nitrogen, water vapor, and carbon dioxide.
What happens if you run out of diesel exhaust fluid? Diesel exhaust fluid is used to reduce NOx emissions. You will get a lot of warnings to refill the DEF tank before you run out. If you decide to ignore the warnings or the circumstances do not allow tank refill, the engine is designed to limit its power and fueling dramatically. This is a form of punishment to the driver if you like, but also it is a way of mitigating and controlling the increase of NOx emissions due to the lack of fluid.
Is it bad if I ingested DEF? Drinking it should be avoided at all costs. If that happens, contact a doctor immediately. Also, refer to any warnings that may be present on the jug or package (if applicable).
What happens if DEF goes into my eyes? If it gets into your eyes, flush with large amounts of water immediately for at least 15 minutes. Consult a doctor if you have any doubts or symptoms that are concerning.
What happens if I spill DEF, how do I clean it up? DEF residue can be easily cleaned up by washing the area with warm water.
Is DEF fluid corrosive?
It is corrosive to most metals used in automotive applications. Carbon steels, iron, zinc, nickel, copper, aluminum and magnesium are some of them. If it comes into contact with any metals, you should clean the area with plenty of warm water to eliminate accelerated corrosion.
Can DEF go bad?
The fluid typically has a shelf life of 18 months. It does not expire technically, but it can lose its water content and the ratio of Urea/Water could change. This will affect engine emissions, since all the calculations in the ECU expect urea to be 32.5% of the DEF solution injected.
How can I check the DEF quality?
Its quality can be easily checked using a urea refractometer (available at Amazon.com). What happens if DEF freezes? How can you keep DEF from freezing? 67.5% of DEF is water. DEF freezes at -11 C or 12.2 F. When DEF thaws and goes back to liquid form, it maintains it consistency. It is suggested that you store DEF at a temperature between 5°C and 25°C (23°F and 77°F).
How do I store DEF?
Store in sealed containers to avoid contamination and avoid direct sunlight to prevent water evaporation. How long can you store DEF? Is there a shelf life? It can be stored for 18 months at a temperature between 5°C and 25°C (23°F and 77°F). For every 5° (9°F) above the recommended temperature, shelf life is reduced by six months.
Is DEF fluid all the same?
All DEF fluids that are supposed to be used in automotive applications should meet ISO 222411-1 specifications. Assuming that all Diesel Exhaust Fluids meet the ISO specifications, they should all be the same.
- Written by The RV Guy
At our RV Boot Camp Trainings, we begin by determining what our audience knows about the operation of large vehicles. See if you need to learn more about driving your RV - test your RV knowledge.
- How wide is an Interstate freeway lane?
- In your State, what is the maximum width an RV can be?
- In your State, what is the maximum legal height a vehicle can be?
- If your motor home is over 40 feet, what do you require?
- What is the weight of your RV?
- What is the height of your RV?
- What is Off-Track?
- In your State, what is the maximum combined length of your truck and RV?
- Can you tow more than one vehicle in your State?
- When towing, what is the legal speed limit in your State?
- What is a Gator?
- What is an easy way to keep your RV centered in the lane?
- Why is it important to adjust your mirrors?
- What is the easiest way to get more miles per gallon?
- If you double your speed, your stopping distance increases by...
- If you double your weight, your stopping distance increases by...
- If you double weight and speed, stopping distance increases by...
- Name the primary braking system when descending a steep hill?
- If you're in high wind conditions, what should you do?
- If there are 3 lanes, in which lane should an RV travel?
- When stopping in urban traffic, how must space should you leave between your vehicle and the one in front of you?
- On the freeway, how far ahead should you scan the road?
- When driving on the freeway, how many seconds should there be between your vehicle and the vehicle ahead of you?
- At 55 MPH, how many feet will you travel in 1/2 a second?
- If your vehicle has air brakes, why is this figure important? Explain the COLA check?
If you didn't know many of the answers, you're not alone. At our RV Boot Camp Trainings, very few non-commercial drivers know the answers.
If the calls we’re receiving so far this year are any indication of what’s happening in the RV Industry, 2020 is going to be the year of the Big RV and Trailer!
Who needs a non-commercial license?
In California if you’ve purchased a motor home that is over 40 feet
in length, you DO require a non-com Class B license.
If you have a 5th wheel trailer that weights more than 15,000 lbs or a bumper tow trailer that weights more than 10,000 lbs, you DO require a non-com Class A license. The good news is that for the majority of RVers, you do NOT require a special license!
In the other states requiring a non-commercial license for a recreational vehicle the criteria is the weight of the vehicle, over 26,000 lbs. These states include Maryland, Michigan, North Carolina, Nevada, New York, Pennsylvania, South Carolina, Texas and Wyoming.
If you live in Arkansas, Connecticut, Hawaii, Kansas, New Mexico, Washington D.C or Wisconsin, check with your local DMV because if your vehicle is over 26,000 lbs you require a Commercial Driver’s License! For the rest of the country and if you’re traveling to Canada, you are good to go!
How you’ll be tested:
In California the testing procedure is as follows; the examiner will inspect your registration papers, your insurance papers and your interim license, all must be current. He/she will then make sure all of the lights and turn signals are working on the RV and if applicable, they will explain the Air Brakes to you and check to make sure there are no air leaks. (In California you do NOT require an Air Brake Endorsement). Then the examiner will have you do three of the four basic driving skills, straight-line backing, off-set backing and 90 degree dockside backing, no parallel parking. To pass the skills test, you must have no more than 12 errors overall. You are allowed to have two “Looks” and three pull-ups for the dockside backing.
Once you have passed the drive skills test it is out on the road to do your road test. The road test is no different than what every commercial driver experiences. To pass the road portion, you must have no more than 30 errors and no marks in the automatic failure section. You will then have your noncommercial Class A or Class B license.
Remember the non-commercial license is just that, NON COMMERCIAL so do NOT try to get one if you’re being paid to drive! If you receive compensation to drive, you MUST have a full CDL.
This in a nutshell is what the non-commercial is all about. Please contact us if you have any questions.
Thank you! Gary