hipower wrote:
WayneLee wrote:
Congrats on your new coach. I was in your shoes some 8 years ago, and I am still learning, especially from the pros on this site.
To get you started, my first, and hardest thing to understand was the function of the accelerator in a DP vs a gasser. In a gasoline motor, when going up a hill, you depress the accelerator to increase engine RPM, and climb the hill. In a DP, the engine and transmission work together. Higher RPM does not mean better. You need to learn the "sweet spot" in your engine, mine is around 1400 to 1700 rpm's, you can usually find the sweet spot on the manufacturers web site. When going up a hill, you keep your RPM's in this "sweet spot" and you let the engine/transmission decide what gear to be in. Coming down the hill, you use your engine brake, or exhaust brake, to keep your speed down and under control, trying to avoid using the brakes as much as possible.
Then, there is the issue of air brakes, which act totally different from hydraulic brakes and feel quite different. Air pressure, supplied by on-board compressors, keep your air lines under pressure and your brakes retracted. Stepping on the brake pedal allows air to release, which then allows the brake pads to come into contact with the rotor/drums (depending on what kind you have). Usually beginners stomp on the brakes, causing sudden jerking in the coach. You will need to get a good feel of your brakes and how feather them to slow down or to stop.
There's a lot more that you will need to learn. Plan on using the "search" feature of this site under the Class A Motorhome category to find out a lot more about fueling, filters, tires, and general handling and maintenance.
Wayne, the info you posted about air brakes is incorrect. Air pressure applies the brakes, not retracts them, except in the case of the parking brake.
You and the OP might be well served by studying an air brake operating manual, like the ones supplied for CDL drivers testing centers so that you both understand their operation better.
OK, I think we have a problem here.........
Air pressure retracts the brakes. It's the BIG SPRING that applies the brakes. Air pressure acts against the spring releasing the brakes.
If your tooling down te road at 55MPH and you start loosing air pressure you better get pulled over and stopped B4 the brakes loose air pressur and lock up!
You see this with the big truck trailer rigs. Bust a hose to the trailer & the trailer brakes lock up!
w/o air pressure the brakes SHOULD be applied by the spring in the air brake canister. Don't know how many unexperienced mechanics get their face torn off while pulling the strap holding the canister. Once that stap gets loose that spring, and all its pressure is released and the end of that canister goes subsonic flying off the back of that air canister! it will kill you if your in it's way!
Their is a specal tool that is used to COMPRESS the spring & lock it into place while pulling apart the air canister.
It is a good idea to readup on how air brakes work. I'm sure someone has some links. I just upgraded my coach. Old rig had Hydraulic disc's on all 4 corners. My 07 Discovery now has air bags/brakes.
Just want everyone to know I'm not an expert on air brakes. Been around my younger brother who has driven sand & gravel trucks for years.
