My education on air brakes is now complete.... http://m.youtube.com/watch?v=42u4v-AbWA ... play%253D1
Happy New Year all.
Air brakes
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- Posts: 24
- Joined: Sun Sep 29, 2013 6:17 pm
- Location: Auburn, Clare Valley in SA
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- Posts: 24
- Joined: Sun Sep 29, 2013 6:17 pm
- Location: Auburn, Clare Valley in SA
Re: Air brakes
Try again with the link https://www.youtube.com/watch?v=42u4v-A ... tube_gdata search YouTube for "how do air brakes work (educational video 1967) if the new link does not work and you have an old bus like mine!
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Re: Air brakes
Hi Bill, If you need an excellent diesel mechanic that doesn't rip your arm and leg off I can recommend one that is over your side of town, well St Kilda way (SA). PM me if you want his details.. 

Queen of the Banal & OT chatter and proud of it. If it offends you then tough titty titty bang bang.
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Re: Air brakes


The bit about air pressure remaining in the trailer tanks to hold the brakes applied is a bit out dated these days, I doubt you would find many systems like that still around, they had a nasty habit of letting the trailer roll away if all the air pressure was lost.
These days, when the control pressure is lost a very heavy spring contained in the second section of the brake actuator applies force against the service brake diaphragm so a mechanical action actuates the brake in a similar fashion to the way the air does in normal operation, by pushing the actuator rod against the slack adjuster which turns the "S" cam and forces the brake shoes against the brake drum. This spring is under very high tension, no attempt to disassembly this chamber should be attempted if you don’t know how to retain the spring fully compressed, serious physical injury will be the result if you get it wrong.
There are a few other components in there that aren't mentioned, the rollers to contact the "S" cam to reduce wear and create a smoother operation and the springs between the brake shoes to pull them away from contact with the brake drum surface when the brake is released.
This video shows how simple "S" cam brakes function, the primary control part pretty much the same for wedge brakes and disc brakes, just the way the actuator applies the pressure to the shoes/pads is a little different. The adjusting method is quite different between the different types though, a video on that one would be very interesting

A person may fail many times, they only become a failure when they blame someone else John Burrows
Those who struggle to become a leader, rarely know a clear direction forward for anyone but themselves
Those who struggle to become a leader, rarely know a clear direction forward for anyone but themselves