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Im not sure exactly what your looking for.
On any air brake chassis the air that is being delivered from the brake pedal is a signal that goes to a brake relay valve. The relay then provides air to the brake chamber directly from the air tank. The air tanks and relays will always be as close to the axle as physically possible. This design eliminates fade and delay. Otherwise axles further would engage and release slower than axles closer to the brake pedal.
So yes there is defiantly components between the pedal and the chambers, the brake relays and the antilock valves too.
In actuality the air coming from the brake pedal TERMINATES at the brake relay valves and it does not even go to the chambers. That air is supplied directly from the air tank by and through the relay.
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Ben,
I think I've been through every component in the braking system. I know of no proportioning valves or air reduction valves.
As Joe said, their are only air control lines from the brake pedal to the relay valves, with one exception. The control air for the tag brakes has to flow through the inversion valve.
The best I can determine brake capacity is a function of the brake pads/shoes, discs/drums, and brake chambers. The brake chamber determines maximum braking pressure. If you have ABS, it's pressure regulators are in the high volume lines going to the chambers.
I would assume the only test would be to measure the air pressure being delivered to each brake chamber. If a relay is obstructing air flow, which would seem remote, it will affect all downstream brake chambers equally.
I will say I'm still trying to fully understand the spring brake relay. It should only be activated by low pressure or manually pulling the push pull handle. With that said, it is also plumbed to the front and rear brake systems. One connection is off the treadle valve.
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The relays r proportionate in relation to the amout of pressure applied to the pedal.
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Have not responded to your threads before Chrismas. Have been busy with lot of family duties and had limited time to worry about the bus. But I got it all finished and took it for my first ride. Went from Northern California to the FMCA rally in Indio in Southern California. I am currently in Quarzside AZ. The brakes feel completely different, but at this time I have not made a hard braking attempt. Will do that next week on my return home. It looks like my repair has been successful. In city traffic, I definitely use less pedal pressure to stop the bus. But I will know for sure next week and will let you know how it went.
At this time I would like to thank you guys for helping and especially Joe for spending so much time with me to get me on the right track. Thank you again.
Ben
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Ben,
It is always gratifying when members help others. Joe is definitely the goto guy when it comes to suspension and braking systems.
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To Joe and Gil,
After driving close to 4000 Miles after the repair of my brakes, I am now able to make an analysis of my brake repair job. There is no comparison what the brakes are like now compared to before the repair. By applying light pressure to the pedal, I now notice how the front of the bus moves downwards a little because the front brakes are catching on. I never had this before, when braking, there was never the downward move of the bus. I feel a lot safer now when driving in heavy traffic like I just experienced in LA and Phoenix.
Again, the repair was sucesfull. I would like to thank Joe and Gil taking the time to help. I would especially thank Joe for taking so much time to go into details to explain and guide me through this job. My advise to anyone else who might get help from Joe: Pay attention to the small details he might be describing, because that is were the quality of the job will be. Thank you again Joe and Gil.
Ben
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Ben,
Great news! I think you have proven that pads build up a glaze reducing their friction with the disc or drum. Just because plenty of pad is still there doesn't mean they still stop like new pads.
BTW, we both know the thanks all goes to Joe. Joe is definitely the under carriage guru.
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That's great news. There was a boatload of stuff we went through and doing it over the interweb.
It's been quite a while u had me nervous.
I think if there were 2 big points it's the washer behind the pinch bolt spindle nut and a good solution for getting the hubs back on the spindle then making sure it's as it was before disassembly.
Attachment 14371
Attachment 14372
Attachment 14373
And here is a painless way to replace that massive hub and rotor without nicking the new seal.
