air brakes vs. pneumatic/hydraulic?
What are the advantages of air brakes over pneumatic/hydraulic brakes when considering purchase of a bus or RV?
- mustangerLv 71 decade agoFavorite Answer
With hydraulic brakes the wheel cylinders (drum brakes) or calipers (disc brakes) are right at the wheels and absorb heat from the braking action. When brakes get hot the hydraulic fluid can boil. When it boils it becomes a vapor, which is not compressible and you wind up with no brakes. Heavy vehicles like buses and RVs take longer to stop hence more brake use and more heat build up. I have seen a lot of RVs with hydraulic brakes experience brake failure in mountain driving where a lot of braking is required. With air brakes the brakes are operated by air cylinders moving mechanical linkage to apply the brakes. their isn't any fluid to heat. You can still lose the brakes by over use and burning the linings but that is a rare occurrence.Source(s): Been repairing and restoring cars for over 50 years. RVer for 16 years.
- Anonymous1 decade ago
The reason heavy trucks use a pneumatic braking system is there pretty much fail proof, there a 2 stage system, on the emergency side they are spring applied and air released, and on the service side they are air applied only, an air tank is utilized to store pressure in case of engine failure, thus giving you some time to get the truck to a stop, once the tank is empty or to its cut off threshold the spring applied emergency system takes over to bring the truck to a stop, short of a major drum and shoe failure the truck will come to a stop without engine power. a hydraulic system with a vacuum power assist is totally reliant on the engine creating vacuum, in the event of engine failure you lose power brakes, and coming to a stop can be quite the ordeal, there are some 12v override systems but they are expensive and problematic at best, then there are some heat issues in extreme conditions also,,
- Randy WLv 51 decade ago
another thing is that hydraulic brakes are quicker than air
air can be subject to getting water and then freezing making them inoperative.
This was an issue in the old days.
Is it still true today?Source(s): me
- Anonymous5 years ago