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Air leaks
I think it has been about a year since I started chasing leaks trying to eliminate “the leans” in my 1986 Liberty XL. Jon told me it could be a five figure chase and he was not exaggerating but I think i can see the the finish line (at least for the moment). Several new Norgren valves, cracked fittings, new brake treadle valve, brake switches, new air dryer, pull valves on all of the brake air tanks and I got a night with no lean and man, do the brakes work better. Now I just need to explain to the kids where their inheritance went.
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7 Replies
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You have done A LOT of excellent testing.
Best I have ever read about.
I STILL have, and cannot figure out why all three of my tanks drain at the exact same rate despite previously thinking I had resolved the issue (by replacing the PR2 Pressure Protection valve at the aux air tank)
I additionally and VERY recently changed the DC-4 valve, R-12s, R-14 and R-7 parking brake valve yet still primary, secondary and aux tanks drain down at the exact same rate.
I have studied and studied and studied the air drawing for my coach and cannot see where all three tanks “meet” or at what point they converge and could potentially cause all three to leak down at the exact same rate.
Incredibly frustrating…
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Check valves are important and I have 3 R12 valves and 1 R14 valves I replaced all 5 years ago If you look at schmatics 3 R12 valves only get air when the control port gets air when you apply brakes, When I seperated air lines between wet tank and pedelvalve it held 4 cheap gauges and some fittings told me alot.
2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL -
Wow Art! That is some mighty fine detective work. Well Done Sir!
2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL -
God bless you Art. You have far more patience than I do. I have had my bus for 5 years, replaced all airbags, Norgen valves, all brake rated air systems, and about 90 per of the push on fittings with compression fittings and have gotten the leaks to a point that my tanks leak down at about 1-2 PSI per hour. I consider that good enough and stop chasing leaks until the leak rate increases.
I do have all 3 tanks leak down at the same rate. I have changed all the check/oneway valves and still have the same leak down rate on all 3 tanks. On a side note, if I dump the air at a fast rate, the check/oneway valves DO WORK. Haven’t made any sense out of that yet.
Chuck
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It makes sense for the check valves to fail from a slow leak vs large. I believe they use seals and when air flows one way it springs open but other it pushes shut. If spring is worn or all is dirty it won’t be pushed shut airtight.
2000 Featherlite H3-45
2024 Jeep Grand Cherokee
Leesburg, FL -
One thing that may help people more easily know where to chase leaks is to understand when the bus is parked there is no air beyond the relay valves so if air in the primary and secondary system goes down it has nothing to do with the air lines or brake chambers.
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Thank you Jon that is good information.
Hope you guys don’t get what’s coming to northwest pa and the southern tier this weekend.
Thanks again,
Chris
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