From: Recovry4x4@aol.com
Date: Fri Jan 09 2004 - 05:25:59 PST
For the betterment of the list and certainly myself, here's what I figured
out with my tractor. The problem was when I opened the valves to supply
emergency and service air to the semi trailer, a whisp of air would come out then
nothing. Same thing on the rear gladhands. The tractor protection valve was
suspect. I've poured over the TMs and air schematics trying to figure out how the
system works. Along the line I received a lot of feedback from the list. This
system differs from the common commercial air brake system in that there are no
cab controls for the trailer air supply with the exception of the trolley
brake. When this valve is working properly it should allow air to escape when the
valves are open until the air pressure drops to between 45 and 20 PSI then
the valve slams shut to prevent further air loss. Some older commercial tractors
have a control in the cab that allows the driver to activate this remotely to
shut off air to the trailer. My valve is stuck in the emergency position not
allowing air to the trailers. There was plenty of crap inside the valve. I
called my trusty friends at White Owl requesting a TP valve. Although they were
willing to sell the valve to me they suggested going to a heavy truck supply
and picking up one locally citing the fact that it's pretty much a commercial
item. I did find a tag on the valve and took it and the valve to the local
Freightliner dealer. With a little poking around they came up with the valve and
although not in stock, it will be there in a day or two. The Frieghtliner guys
were very helpful and allowed me to look over their books and select one of 3
valves that will work. The new valve has a port to allow remote activation so
I'll be plumbing in an air switch in the cab for remote operation. Many
thanks to those who contributed to my problem as well as George Kivett and the gang
at White Owl for their honesty and help.
Kenny
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