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Pneumatic Brakes Sad
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Posted by: NC

08/30/2005, 10:55:53

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I need a quick refresher to brush up on pneumatics, systems, (relay) valves, and schematics. Can anyone recommend relevant sites and/or help me out?
I'm looking to come up w/ an auxiliary air supply to tap into an existing brake system without adversely affecting the main system; this aux systerm would end with a type of quick disconnect to link to an external braking system. This requires an understanding of the main air disc brake system, its schematics, and what components are necessary to make the auxiliary system. All I know at this point is an additional reservoir, relay valve (what kind?) and additional fittings and plumbing.






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Re: Pneumatic Brakes
Re: Pneumatic Brakes -- NC Post Reply Top of thread Forum
Posted by: randykimball
Barney
08/30/2005, 19:14:34

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... are you putting a "toad" behind a motor home coach?
..I did that, if you are...
-randy-



The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them.


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Re: Pneumatic Brakes
Re: Re: Pneumatic Brakes -- randykimball Post Reply Top of thread Forum
Posted by: NC

08/31/2005, 08:19:36

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I guess not since I don't know what a "toad" is. Are you referring to a Gladhand connector? I know it'll be a quick disconnect type of connector which will be similar to the Glandhand.






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Re: Pneumatic Brakes
Re: Re: Pneumatic Brakes -- NC Post Reply Top of thread Forum
Posted by: randykimball
Barney
08/31/2005, 22:33:33

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big giggle.... I needed that today.. thank you!
A "toad" is the vehicle that is towed behind a motor home or coach.

I spliced into the air line between my rear air brakes on my coach and ran a quick connect to my Land Cruiser "toad". Then I put an air cylinder that is easy to connect and dis-connect to my Land Cruiser brake pedal. I then have excellent proportional brakes on my "toad" when it is being "towed"... OK?
...works like a charm..

-randy-




The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them.

Modified by randykimball at Wed, Aug 31, 2005, 22:38:34

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Re: Pneumatic Brakes
Re: Re: Pneumatic Brakes -- randykimball Post Reply Top of thread Forum
Posted by: kelly_bramble cragyon, cragyon

09/01/2005, 09:29:51

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Thanks for the definition Randy, I've never heard that particular slang used before. I wonder how this came about?






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Re: Pneumatic Brakes
Re: Re: Pneumatic Brakes -- kelly_bramble Post Reply Top of thread Forum
Posted by: randykimball
Barney
09/03/2005, 00:15:18

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Hi,
I'm thinking towed from a bunch of fun loving RV'ers and retired people became "toad". A case of an adverb becoming the noun. Towed Toyota Land Cruiser is a lot longer than "toad".

.. ya think?

-randy-




The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them.


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Re: Pneumatic Brakes
Re: Re: Pneumatic Brakes -- randykimball Post Reply Top of thread Forum
Posted by: NC

09/01/2005, 09:22:11

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Thanks for the clarification; I now know what a "toad" is
That sounds very simple. All you needed was an air cylinder, tees and connectors, and extra air hoses. No additional reservoir and relay valves? Did you consider the additional air volume, since you're tapping into the air reservoir of your motorhome? Can you fill me in on the air cylinder, like how it's connected to the "toad's" brake pedal, strokes and/or volume, etc? Any recommendation on the manufacturer or cylinder or entire tow brake system?






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Re: Pneumatic Brakes
Re: Re: Pneumatic Brakes -- NC Post Reply Top of thread Forum
Posted by: randykimball
Barney
09/02/2005, 23:56:24

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Sure, Use a 1-1/4 dia. single action cylinder from SpeedAir handled by W W Grainger. ... about $25 or so. 1-1/4"at 100 PSI comes close enough to 100 lbs of force at full brake application. This is what I figured I needed on my rig by doing some hard stops without any boost from my booster. I made a connection bracket to fit the seat frame and the clevis at the end of the cylinder. This bracket must allow the right height to get good leverage to the pedal and be able to handle the forces. On the rod end I purchased the screw on clevis and made it fit over a bracket that I bolted to the brake lever just above the pedal pad. All go together with snap lock pins. There is plenty of air to handle this tiny cylinder and in fact there are products out there for quite a few $$ that do just this.. (I think one is called Brake Buddy)... you TEE the air line to the brakes between the rear cylinders at one end or the other with a standard hydraulic TEE.... You must take care not to allow a possible leak in the future.. use good steel braded air line with 1/4" ID.. this means a presure drop until the cylinder reaches critical push on the brake, but this gives you a buffer time and if you really need brakes you will get plenty of stopping (at least I do). I tested mine on loose gravel and was very impressed. I used standard quick disconnect parts of the Milton 700 family, one at the cylinder, one at the hitch. The line stays on my toad all the time. I can install the cylinder and plug it up and be ready to roll in about two minutes or less. (Then I put diodes at all the tail and brake lights and run them off the Coach, too.)

No reservoir... you don't want any accumulation of air nor delayed brake release. The stroke is whatever it takes to press your brakes hard plus an inch for good measure safety factor. A couple or three inches extra hurts nothing because the brake pedal will hold the cylinder ready to go at the right stroke all the time. No, don't tap the reservoir on the coach, this is brake action presure, you get air when you press the brakes accordingly to how hard you press. Put a TEE between the wheels. There are two air brake systems at the rear wheels. One locks the brakes down if their is no air supply, this is the emergency lock-up system. A spring pushes the brake shoes closed, when you have service air this spring is over come by the service air, ... and dumped when you pull the air brake valve at the cockpit. Then there is the air brake system, it provides air according how hard you push the brake pedal. They go to two different chambers. When there is service air the outter most chamber is charged and withdraws itself from effecting brake action. If air pressure (service air) is lost the emergency chamber over rides and locks the brakes down.

Disclaimer.. you are on your own. I did this and it works, I can't know your skill level nor your brake systems. I don't know if your coach or truck warranty allows. OK?

-randy-




The worst suggestion of your lifetime may be the catalyst to the grandest idea of the century, never let suggestions go unsaid nor fail to listen to them.

Modified by randykimball at Sat, Sep 03, 2005, 08:52:02

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Re: Pneumatic Brakes Smile
Re: Re: Pneumatic Brakes -- randykimball Post Reply Top of thread Forum
Posted by: NC

09/06/2005, 08:18:22

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That was very educational. Thanks much.






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