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Tag axle brake overrule control
The norgren valve to control this function on a 98 45XLE is normally located where? I am rebuilding a fire damaged coach and everything from the differential back is gone. Is this controll on the rear out side of the last bagage bay with the rest of the air bag controls? There is one there with a green (brake control) air line going to it. Does the supply to this control come from the primary air tank located above the right rear drive axle.?This is the last part of the puzzle and I’m done. I have the diagrams but they show how it works but do not refer to specific location. Thanks Bob.
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5 Replies
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Bob,
I’m not familiar with a brake over rule valve, could you explain further?
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When you lift your tag axle ; your coach disconnects the service brake feature to the tags. Like some have pointed out their function just takes weight off tags. If the brake function was not disabled the tags would skid at a slight brake application. Bob
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Bob,
I am on the road and do not have easy access to the large pneumatic diagram for my coach that I made by blowing up the PDF files Prevost has on line, but I do know that above the tag axle is a valve whose function is similar to that of a Norgren. It is mounted on the dirver’s side on the frame in line with the Norgren that controls the air path between the tag axle air bag and the drive axle air bags.
That valve controls the tag axle lift so without looking at the diagram I suspect that valve is central to the portion of the system that lifts the tag axle, while disabling the air flow to the service brake side of the tag axle brake chambers. What I do not know (because I never looked) is how that performs that function. If I had to guess it probably controls a relay valve that it holds open when the tag axle is down to the path to the tag axle service brake is open, and shuts off air to the relay valve when the tag is lifted. It likely is functioning like the brake treadle which sends air signals to the brake system relay valves. If Hector is reading this perhaps he can access the drawings easier and offer the correct answer. My answer is only speculation.
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Since fire a skeleton of There is just one left there above right rear wheels . Was just wondering if someone had been into theirs lately and remembered where it was located. Have found out for most part drawing are correct but with occasional revisions/locations. Trying to match what is left of plastic (melted) air lines with drawings. Going to pull control line off norgen valve (un affected by fire) on ouside of rear of rear bagage bay and blow air into it and see if it come out flip flop control valve for lift …..Could be tomorrow today just could be a lazy day off. Said valve has a green brake indicated line going to it. need to put brain around it…. lot easier to just change parts out. Bob
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was on drivers side near tag axle beam. I had just overlooked it. The green on the I saw on the norgren valve was denoting which air bags it was controlling for leveling system.. Turned out to be dual control norgren valves. Thanks for info and patients. Bob
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