DougBarr32

Thank you all for the amazing help. We will get this narrowed down soon.

So are you possibly saying the air leak should be between the air supply and the pressure valve ? Not after the valve correct ?

My mental road block is loosing 25 psi in 5 min when running out of the front tank. When parked it does not loose all of the air in 15min. After a few days it goes down to about 65psi. ?

Thank you for your response. I do have a schematic from freightliner of the air system. It has color coded air lines listed as well. I have sprayed down the lines going up to the front of the coach with no luck. And no air noise. Good idea on the Tiffin chassis additions. Maybe they have a schematic on there part of the air system. The air dryer purges every 5 min. With the front tank psi going up and down. Any Additional thoughts.

Joe, I isolated the mac valve from the air step cylinder ( the mac valve does not leak on its own) the cylinder will need rebuild it or replaced. Air Leak, At this point on the the front tank pressure goes up and down as the engine is running in my driveway and while driving 120psi-95psi.( about every 5 min) The odd part is I have soap sprayed down the tank system in the front,the valving,the front air bags, and the front leveling valve. The leveling valve is seeping just a little bit at the connection over time. So my finding is when engine is running the front air is cycling so I am asking for help with this: What in the air system is turned on or opens up when the engine is running If I can determine this I should be able to find and correct the source of my cycling issue. If anyone has any help they can offer I would appreciate it. Thank you, 05 Tiffin bus XC chassis

It took me a month or so but I have what looks like to be my leak. I replaced my Haldex air dryer and replaced my tank pull air drain fittings. I sprayed down the complete air tank area and found some connections with small leaks so I took care of them while I was there. With no apparent big leak I was frustrated. In looking at the tank design and watching both gauges continuing to lose air at the same rate I went back to the drawing board. It has to be a tank circuit that joins both tanks together. So with all that said on the 05 Tiffin Bus there is a customer air manifold mounted in the left front lower electrical compartment. It supplies air to the inside air powered step cover. The Mac valve is leaking air out the exhaust port constantly. I have heard the Mac valve could not be sealing the exhaust port or the air piston in the step cover could have worn seals in it witch can cause the exhaust port to leak as well. Any help to resolve this issue would be appreciated. Thank you. Doug,

I have done some more testing on this issue the coach is making a fluttering sound or you could call it light honking sound coming from the underside in where the air tanks are located when the system is fully pressurized. Also I pressurized the system and let it sit for three days when I turned the coach back on the front air gauges read 60psi and the rear air guage reads 95psi. Very interesting because they both seam to drop or loose air psi at the same rate of loss. So i charged up the air let it blow off then turned off the engine and watched the gauges. both gauges went down at the same rate over 12-15 min it was at about 105 psi-- both front and rear. Any thoughts on this continuing issue would be appreciated. I have ordered new tank pull drain valves and also a complete air dryer assembly to replace the old one. I do not know the last time it was serviced so I think it best to replace the complete unit . Haldex da 34160

Sorry for the delayed response. I will air up and allow the the purge valve to blow off, turn off the engine, then time the pressure drop to 95psi and also look and listen for the leak. I will get back with you as soon as I can. Thank you for your help.

Yes it takes about 6-7 minutes for the pressure to drop and the compressor to come on. I tested this sitting in the driveway ebrake off wheels choked no brake applied. Both frt and rear brake gauges drop at the same rate.

Looking for some help please. '05 Tiffin bus. When the air system is fully inflated engine running the the pressure cycles constantly from 125 to 95 and back and forth driving down the road with no brake action taking place. Any thoughts.

Does anyone know is the inlet flapper usually located in the water bay behind the white panel where all of the controls are in the water bay ? That sound like it could be the issue. When you are running water through the system the water line connected to the hose reel when you grab it is vibrating. This is with the holding tank lever valve closed and the pump off.

I have a 2005 Tiffin Bus and when we are using the water in the coach meaning someone turns a faucet on or the shower is being run a fluttering/whining noise in coming from the water inlet line that is bringing the water from the hose reel up into the coach. any thoughts ?