Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 13, 2025 ...

Air leaks

August 27, 2016, 11:01:12 am

I have been trying to find air leak in the system, I hear that it is common to leak some air, 120 PSI late yesterday about 5 pm this morning at 7am it is 75 PSI so 14 hours it lost 45PSI , where did it go, I put a plug in wet tank for now till relief valve shows up, And I know the 2 other tanks Front/Rear are protected with check valves. Rear tank was empty when I removed check valve and other tanks had air still in them. Also both needles drop evenly the seem to stop at low psi 20 or so pounds. Looking at drawings what would make them drop the same? Brakes system?  Also it's up on supports and I rolled all around and can't rear or see any problems

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Re: Air leaks

Reply #1 – August 27, 2016, 04:43:08 pm

You may have to use a spray bottle with dish soap and water to find the leaks, that much loss is a small or most likely several small leaks that the only way you can find them is to go looking for bubbles.
Don't to forget to spray the drain tube on the wet tank also the 6 packs, ride height valves and Alison accumulator air valve.
our coach loses 50+ lbs in 4 hours, so far have found several leaks but not the big kahuna yet.... 

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Re: Air leaks

Reply #2 – August 30, 2016, 02:44:48 am

I'm having the same issue, with a loss of 40lbs in 8 hours. will have to get under and start spraying.

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Re: Air leaks

Reply #3 – August 30, 2016, 12:32:38 pm

40 psi in 8 hours is probably DOT acceptable, an no problem if your engine compressor can keep the tanks at correct pressure.

And looking for leaks with spraying may not yield anything as many 'leaks' are internal from check-valves being worn.

Nice to have a tight air system, but may not be necessary for safe driving.

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Re: Air leaks

Reply #4 – August 30, 2016, 01:15:56 pm

Before you crawl underneath (Use safety props on the suspension!!) look at the parking brake valve on the dash as well as the horn system.  Often missed.

Might save some work.

Keith

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Re: Air leaks

Reply #5 – August 30, 2016, 01:24:57 pm

Besides the dish soap and water spray, I use a stethoscope with a long hose no metal end. It found my mystery leak on the crane yesterday. Air was passing through the D-2 governor and out the intake of the air compressor. Soap spray couldn't get that large of an opening.

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Re: Air leaks

Reply #6 – August 30, 2016, 03:53:57 pm

A suggestion for possible leaks if you have the pneumatic drop down step and the air operated inside step slide cover. Both big culprits in my view.
BTDT
JohnH

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