School Bus Hydraulic Brake System simple test for leaks..CDL

In a hydraulic brake system, when the brake pedal is pressed, a pushrod exerts force on the piston(s) in the master cylinder, causing fluid from the brake fluid reservoir to flow into a pressure chamber through a compensating port. This results in an increase in the pressure of the entire hydraulic system, forcing fluid through the hydraulic lines toward one or more calipers where it acts upon one or more caliper pistons sealed by one or more seated O-rings.

[@ferrariunicorn]

So glad you put the headlights on before starting!!!! Countless pre-trip sheets don’t state that & was told “its because you are testing in the day time for an inspector” and my comment was “teach it the right way - as if it is dark out - so that when you are doing your pre-trip, Which We Do Every Day, through season changes (and lighting changes) it will promote consistency which is key! Especially since drivers aren’t re-taught how to ‘do it the right way’ after they pass the test; which leaves drivers to doing some guess work, which causes change and inconsistency!! Fell On Deaf Ears SMH Again Thank You!!

[@suleman391]

Thank you sir. Good instruction to the point. Clear, precise.

[@mallorymcguire833]

........in the first part of the test where you're pressing the service brake three times and holding for five seconds, you forgot to say "the brake pedal should not move (depress) during the 5 seconds." This is in the DMV handbook. If the brake pedal moves, then you know there's a leak somewhere, because the pedal still moves after it's all the way depressed, meaning pressure (fluid) is being released somewhere in the system.

[@dwitcraft]

Hi, this is how we are taught to test, I drive an IC 23 seater(custom body, still hydraulic brakes). My question is why we pump 3 times. In any other vehicle with hydraulic brakes, we want it to work correctly on the first pump!

[@brysonmoonan]

Love these videos! Good job boss man!

[@margaritaortiz6055]

Thank you, you save my life!!

[@schoolbus1014]

You are welcome.😎

[@jannixon6299]

Should the parking brake be on when you press on the service brake at the beginning of the test?

[@schoolbus1014]

Yes, it’s recommended

[@Hawqis1]

Not sure I understand why putting the headlights on is part of the brake test. I love the full air brake system. If you lose pressure, the brakes apply. Hydraulic system loses pressure, you roll. I've had 2 buses with hydraulic brakes and a personal car fail while in operation. All of which I kept the vehicles under control. Big buses don't have a park gear so shifting into 1 helps slow down. On the car, it was a 87 Ford Crown Victoria with no brake warning light at all. I put it into park gear and it skidded under the red light. I had my other hand on the horn to alert others of a problem. I don't care if I wreck the transmission, with family in the car, a wreck with another car wasn't an option.

[@BusMaster99]

You should never use your park pawl to try and stop your vehicle in an emergency. Use low gears FIRST and then apply the parking brake if you need to stop or slow down further.

[@ManzaMvsa]

Thank You!!!

[@rosacruz0404]

Great video thanks

[@Beauty-ut5fz]

Thank you

[@HarryJCLK]

Damn that simple?

[@hlc5145]

Hi

[@2ndgencadi189]

Hi from 3 years in the future

[@bucketsdoo5252]

My instructor said school buses don’t have air brakes , she said they have hydraulic brakes , I don’t even get it to be honest

[@christinalundberg6878]

This is not true. Our Thomas buses have air brakes.

[@staceybridgeman8245]

Depends on the bus.

[@Beauty-ut5fz]

@@staceybridgeman8245 Yes that's true. Where I'm training mine have hydraulic brakes.

[@jannixon6299]

Some school buses have air brakes and some have hydraulic brakes.

[@sosexy9701]

When you checked for leaks, did you have your emergency brakes set?