MIDNIGHT RIDER
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- Sep 29, 2005
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That second vacuum-pump is for trailers with REAL BRAKES, not some wimpy electric crap.
All of my engines have two vacuum-pumps, one for the truck, one for the trailer.
If you look adjacent to the goose-neck hitch, you should see a plate, with a REDLINE sticker on it, that holds two vacuum quik-couples; one is SUPPLY, the other is CONTROL.
The SUPPLY keeps constant vacuum on a BIG vacuum reservoir/tank that resides inside the trailer's neck.
The CONTROL operates a HUGE vacuum-booster that is coupled to a big hydraulic master-cylinder, also under the trailer's neck.
Located on the trucks left-front wheel-well is the vacuum brake control, to which is connected a hydraulic line from the truck's master-cylinder, a vacuum supply hose from the second vacuum-pump, a pair of wires that control a low-vacuum warning light and buzzer, a vacuum gauge line, and a hand-cable for testing the trailer's brakes and manual control of the trailer's brakes in the event of failure of the truck's hydraulic system.
Vacuum-over-hydraulic brakes are second only to full air; they will STOP and stop hard.
My loaded trucks/trailers stop much quicker than a naked truck.
Separation of either vacuum hose between truck and trailer will immediately apply/lock the trailer's brakes, far better than some silly "breakaway" battery system and electric brakes.
