Rob Posted April 29, 2008 Share Posted April 29, 2008 Tonight I installed a new valve for the tractor brakes. It is the one with the blue round mushroom shaped handle on the right. It is also for tractor brakes only. The old valve did not pop out when the yellow brake release handle was pulled out and the new one does. To release the brakes on the tractor, you now have to first push the yellow knob in, then push the blue knob in. Also the new valve has a spring behind the shaft pushing the valve out when there is no air applied to it. The old one does not. There was really nothing wrong with the operation of the old one but the shaft for the knob was 1/4" in diameter, the new one is 3/8" in diameter. The only replacement knobs I could find were the 3/8" shaft size so I decided to change the valve.Is this normal or do I have something plumbed incorrect?Thanks,Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/3687-air-valve/ Share on other sites More sharing options...
theakerstwo Posted April 29, 2008 Share Posted April 29, 2008 Tonight I installed a new valve for the tractor brakes. It is the one with the blue round mushroom shaped handle on the right. It is also for tractor brakes only. The old valve did not pop out when the yellow brake release handle was pulled out and the new one does. To release the brakes on the tractor, you now have to first push the yellow knob in, then push the blue knob in. Also the new valve has a spring behind the shaft pushing the valve out when there is no air applied to it. The old one does not. There was really nothing wrong with the operation of the old one but the shaft for the knob was 1/4" in diameter, the new one is 3/8" in diameter. The only replacement knobs I could find were the 3/8" shaft size so I decided to change the valve.Is this normal or do I have something plumbed incorrect?Thanks,Rob The valve is wired up right i have seen them both ways but i do not know which way dot wants it to work but it will work ok like that. Quote glenn akers Link to comment https://www.bigmacktrucks.com/topic/3687-air-valve/#findComment-18690 Share on other sites More sharing options...
ThaddeusW Posted April 29, 2008 Share Posted April 29, 2008 Sounds right to me. Before the single manifold valves you coulden't charge the trailer brakes while the yellow tractor valve was out. So they put a third blue valve between the yellow and the tractor spring brakes so you could push the yellow knob in which allows the red knob to be pushed in. Then you just keep the blue valve out to keep the tractor parked while you charge the trailer or hook whatever to the emergency/supply line. Then to park the whole lot just pull the yellow which should cause the red and blue to pop back out. Quote -Thad What America needs is less bull and more Bulldog! Link to comment https://www.bigmacktrucks.com/topic/3687-air-valve/#findComment-18691 Share on other sites More sharing options...
Rob Posted April 30, 2008 Author Share Posted April 30, 2008 Thanks guys, it works well, just different. I'm getting ready to put it on the road next month and want everything working right.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment https://www.bigmacktrucks.com/topic/3687-air-valve/#findComment-18697 Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.