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Old 03-15-2019, 05:28 AM   #1
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Tapping into Air Brake Line on 2014 45í Bus Powerglide Chassis for Toad Braking

I need to tap into the air brake line on a 2014 45í Bus on a Powerglide Chassis for the M&G Brake installed in my toad. I have the Tee valve, Female Air connector and hoses from M&G.

What is the best place to tap into the air brake line?

Any other tips or things to watch out for?

If you have pictures to share that would be most appreciated.

2014 Tiffin Allegro Bus 45LP; 2016 Jeep Wrangler Unlimited
Blue Ox Aventa LX - M&G Brake System
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Old 03-15-2019, 07:55 AM   #2
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I did not want to cut any air lines on mine when I installed the M&G system. I added a short union, tee and a 1/2"-1/4" compression fitting on the line to the rear air brake.
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Old 03-15-2019, 08:05 AM   #3
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Unfortunately my rig came tapped for a braking unit. I say that because rather than "T" off the rear splitter they just cut into the air line after the splitter and before the caliper. Works OK but I worry about the possible air volume difference and line breaking.
2009 45' Magna 630 w/Cummins ISX 650 HP/1950 Lbs Ft
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Old 03-15-2019, 08:50 AM   #4
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I think you are right to be worried. The additional air volume to supply "tow car" air brake system could cause uneven braking on your coach if the tee is between the Relay valve and the caliper.

Probably not enough to be dangerous - but maybe cause uneven brake pad wear.

If I were adding tow-car braking system, I would tee at the "delivery" port to the Relay valve, so the application air from the brake pedal is equally applied to tow-car and coach brakes.
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Old 03-15-2019, 08:40 PM   #5
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The proper way to do this and the only version approved by OEMs as well as the Federal approval is SMI Airforce One. They add a separate manifold, control valve and ping tank. This provides proper proportional braking to the toad but protecting the coach brakes from an air leak.
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Old 03-16-2019, 04:04 AM   #6
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Since you have the M&G system, call them and ask their opinion. We have the M&G system on our toad and these folks are very knowledgeable and helpful over the phone.
May your smiles be many and the miles be plenty.

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Old 03-16-2019, 04:29 AM   #7
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MSTURTZ has a good point on proper way to do this, and there is a valid reason for the extra breaking axle to have its own air tank.

Approved by OEMs as well as the Federal approval is one, and the proper proportional braking to the toad but protecting the coach brakes from an air leak is the most important.

What ever you do, be sure you do not plumb in between a relay valve, and an ABS valve to any one side of an axle. Air volume difference could become a real concern under emergency braking conditions.


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air, brake, chassis, power, toad

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