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Topic: Loss of air on top of continental divide (Read 429 times) previous topic - next topic

Loss of air on top of continental divide

Pulled over on top of the divide going West from Butte Montana to take a breather and check a few things.  Started to get under way again and noticed that I was loosing air pressure and the compressor was not keeping up.  When I stepped on the brake peddle, I could hear an air leak around the rear duals on the drivers side.  I couldn't locate the leak, so 3 hrs later I had a service truck there and we found a leak in the line to the cruise control.  I started up and pressure came up fine and stayed there.  We got under way down the West grade and I noticed again that if I held the brake peddle down, the green bank would slowly keep loosing pressure.  I made the decent in 2nd/3rd gear and used the PAC brake to control speed.  I could stop OK, but couldn't keep pressure on the brakes as the air would slowly leak out.  The red side air bank was OK,  at this point any way.  Got to bottom of the grade heading West on I 90 and noticed that I was loosing air on the red side now.  I pulled over and found that the air line that we fixed on top had broken again just upstream of the repaired area.  Since it was the cruise control that was affected and I don't use it anyway, I clamped it off with a pair of vice grips.  When I started up, the air came up fine and I had brakes again.  I also still had the leak on the green side, so it was slow and easy going to a repair facility. 
  The reason for this post is to point out the cause of these air leaks: 
  The air lines that feed the cruise control and the accessories are a plastic of some kind and are routed in a major race way close to the exhaust manifold and the turbo.  This race way is shielded some what by an asbestos wrap.  The wrap, however, didn't cover the race way far enough and it appears that heat had been getting to these hoses over time and that pull up the East side of the divide was the finishing touch to them.  I have the hoses repaired and have installed additional heat shielding to the race way.  Needless to say, I will be keeping a close watch on air pressures for some time to come.
  I recommend that anyone that has an installation with heat sensitive hoses, etc., check to make sure that no damage has been done and that components are adequately shielded.  This was a close one for us and could have been devastating, only by God's grace did we get through this.  Have a great day  ----  Fritz