Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
I have always found it funny that any fool with enough money or credit can purchase and drive an RV up to certain weight or size and NOT have to get a special license.. AND most of these people you would NOT want behind the wheel of one....
Sorry, but wrong again. You apparently missed my point that "air brake systems are safer" because of the duality of the parking (spring) brake actuation compared to hydraulic service brakes having no automatic parking brake actuation upon failure of the hydraulic system.
The service brake air system and lines are one unique set of components.
The parking brake air system and lines are one unique set of components.
The only thing they share in common is that the parking brake spring actuator assembly is "piggybacked" on the service brake assembly so that the mechanical portion of the brakes are applied whenever either system actuates to apply the brake.
The following addresses your mistakes better than I wish to take the time to bother with.
What could make them safer is that in the event of a loss of pressure the brakes apply vs a hydraulic system that in the event of large fluid loss, well, you're up a creek without an anchor, as in you aren't going to stop unless you're smart enough to hit the mechanical actuated E-Brake and are smart enough to keep it adjusted up enough to work.
With hydraulics you (now) have disc brakes instead of drum, some opine that those are better...
These states that require a non-commercial special license to drive RVs:
California
Connecticut
Georgia
Hawaii
Illinois
Kansas
Maryland
Mississippi
North Carolina
New Mexico
Nevada
New York
Pennsylvania
South Carolina
Texas
Wyoming
Thank You for posting that most informative video which proved my points.
It clearly shows at 45 seconds the foot actuated brake pedal, and at 55 seconds shows the air diagram schematic with the SEPARATE air system for the service brakes and the "spring" parking brake. If you look at the cut-away picture of the assembly, you'll see that there are two air connections to the brake actuator ... one for spring brake release and one for service brake application. When the Spring Brake is compressed by air application, it allows the brake actuator rod to retract. But the other portion of the brake application rod in the service brake air chamber section is now free to extend from the spring brake portion and apply the brakes. The spring brake is still held back by the air pressure of that system so the vehicle can drive down the road with the brakes released. The key here that the service brakes and the spring brakes utilize the same brake shoes to apply the braking force; ie, there's not a separate parking brake friction system from the service brakes with "S" cam drum brakes as are typically found on school buses and semi's.
Sorry, jimj ... but all you've done is prove that I'm correct in how these air systems operate. They are two independent air systems with their respective control valves and air application lines to the respective portions of the brake actuator assembly.
I spent years as a senior tech at Denver Peterbilt working on semi-tractors, diagnosing and repairing these systems. For the most part, they're pretty durable and have a good safety record ... but now and then the hoses or air supply can fail. Especially when the industry went to a weight/cost savings measure of switching from aeroquip style hoses to plastic hoses which couldn't take as much damage from road debris, abrasion, or accidents as the older style hoses, we saw a lot more hose and fittings replaced than previously.
PS: I'll bet that you've never had the pleasure ... as I have ... of having to "cage" a spring brake assembly using the "t-headed" manual release bolt so that it could be by-passed (released) for service work on a brake actuator assembly. Or having to cage all of them on a semi when the emergency brake valve failed on a rig out on the road and the driver wanted to bring the unit into the shop for repairs ... my last road call like that was on a snowy Sunday night in Chadron NE in -10F temps and strong wind gusts.
Location: San Ramon, Seattle, Anchorage, Reykjavik
2,254 posts, read 2,739,837 times
Reputation: 3203
Quote:
Originally Posted by beer belly
....you can't just drive these things like cars.
Thank goodness. I can't say Ive ever seen a retiree in a huge RV cause an accident. But I saw 3 separate groups of car drivers decide to crash into each other just on this morning's commute.
I have always found it funny that any fool with enough money or credit can purchase and drive an RV up to certain weight or size and NOT have to get a special license.. AND most of these people you would NOT want behind the wheel of one....
Most of those driving big motorhomes seem to do a very good job of it; at least that's been my observation. Most of them have been saving all their lives to live it well in retirement, and they don't want to wreck that million dollar rig. I drive I-90 quite a bit in Wyoming so see a lot of them. Most seem to do as well as any professional bus driver.
Quote:
Originally Posted by Cloudy Dayz
These states that require a non-commercial special license to drive RVs:
California
Connecticut
Georgia
Hawaii
Illinois
Kansas
Maryland
Mississippi
North Carolina
New Mexico
Nevada
New York
Pennsylvania
South Carolina
Texas
Wyoming
Required in WYOMING!? Never heard of it, and I've been hauling RVs for most of the past few decades. Good thing mine weren't real big. I'll have to check that out.
I have always found it funny that any fool with enough money or credit can purchase and drive an RV up to certain weight or size and NOT have to get a special license.. AND most of these people you would NOT want behind the wheel of one....
That’s the American way. Money takes precedence over human life’s. Money talks you can buy anything if you have enough $$$ is more important than a human life.
Thank You for posting that most informative video which proved my points.
It clearly shows at 45 seconds the foot actuated brake pedal, and at 55 seconds shows the air diagram schematic with the SEPARATE air system for the service brakes and the "spring" parking brake. If you look at the cut-away picture of the assembly, you'll see that there are two air connections to the brake actuator ... one for spring brake release and one for service brake application. When the Spring Brake is compressed by air application, it allows the brake actuator rod to retract. But the other portion of the brake application rod in the service brake air chamber section is now free to extend from the spring brake portion and apply the brakes. The spring brake is still held back by the air pressure of that system so the vehicle can drive down the road with the brakes released. The key here that the service brakes and the spring brakes utilize the same brake shoes to apply the braking force; ie, there's not a separate parking brake friction system from the service brakes with "S" cam drum brakes as are typically found on school buses and semi's.
Sorry, jimj ... but all you've done is prove that I'm correct in how these air systems operate. They are two independent air systems with their respective control valves and air application lines to the respective portions of the brake actuator assembly.
I spent years as a senior tech at Denver Peterbilt working on semi-tractors, diagnosing and repairing these systems. For the most part, they're pretty durable and have a good safety record ... but now and then the hoses or air supply can fail. Especially when the industry went to a weight/cost savings measure of switching from aeroquip style hoses to plastic hoses which couldn't take as much damage from road debris, abrasion, or accidents as the older style hoses, we saw a lot more hose and fittings replaced than previously.
PS: I'll bet that you've never had the pleasure ... as I have ... of having to "cage" a spring brake assembly using the "t-headed" manual release bolt so that it could be by-passed (released) for service work on a brake actuator assembly. Or having to cage all of them on a semi when the emergency brake valve failed on a rig out on the road and the driver wanted to bring the unit into the shop for repairs ... my last road call like that was on a snowy Sunday night in Chadron NE in -10F temps and strong wind gusts.
In your smugness you forget that at the start of it all it's supplied by the same compressor and main pressure tank AND the same main feed hose. It is NOT two separate closed systems yes, it is split past the main pressure tank with a small parking brake tank so the spring brake will stay pressurized while one drives but if the main feed line or anything prior to that fails the whole system fails and the vehicle stops.
The big thing that RV'ers need to remember is that the spring brake system is NOT on the front wheels. This has and does come into play when leveling the rig and bringing the rear wheels off the ground (something Semi's don't ever do). RV's have rolled away due to this issue.
Now to answer your other statement, at 21 I cut my teeth on semi's as a heavy (big rig) tow truck driver, you know the guys who actually have to figure out how to bring the rigs into your shop by pulling axels,drivelines and either airing up or disabling the parking/service brake systems 24/7 no matter the weather.
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.
Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
