Newell Gurus

Full Version: Air dryer and tanks
You're currently viewing a stripped down version of our content. View the full version with proper formatting.
Hello to everyone and thanks for warm welcome !
 I am looking at getting the air brake /suspension systems working properly on the 86 , coach #89.  After the 700 mile initial trip home I noticed an oily spray on the side of the muffler . No oil evident in exhaust exit . Turns out the copper tubing coming from the air dryer /heat exchanger vent was routed into a hole in the side of the muffler . The tubing had broken just outside the muffler and was spraying the air dryer exhaust on the side of muffler . The compressor builds air in about two minutes or so , but I was concerned about it blowing oil into the system . I went through the air dryer ( CR Brakemaster Model 68 ) and found a film of " oily water " . No dirty, black oil , only what you would would have with a small amount of water with a few drops of clean oil . No liquid actually standing , just a film. No "black " oil in tube either . The dryer has been cleaned and serviced with new check valve and dump valve kits from SKF . Have not reinstalled yet .
 I am trying to find the air tanks and drains . Located a vertical tank , driver's side forward of bellhousing , with a drain cock . Hardly a drop came out , but I now believe this is the catch tank for the air box drains . I have now found a drain cock on what appears to be a lateral frame member ? It's forward of the trans and looks to have lines coming out the top heading to the rear brakes , etc. I did not get a look at the top , only the bottom . Drain cock looks to be plugged with dirt , probably last drained during Reagan's State of the Union address. Have not attempted to open this valve yet . I found drain cocks toward the front , two for the fuel /water separators and one in a rectangular box below the main fuel tank . I must be missing something somewhere . 
  Coach drives very well ( the thing that sold me ) , feels level on the road and stands right up soon after start up . However , the driver's side lowers after being parked for a few hours , seems to be worse at the rear . I will chase down the leak , but the 120 v compressor doesn't work . There is no voltage going into the compressor , not sure if there is a switch somewhere or if it's because I have the coach connected to a 30 amp power source at the moment. 
There are two female quick connects , one at the compressor ( forward of driver's front wheel ) and one in passenger engine bay that's connected to manifold(s) , electric/air solenoids , a gauge and blue tubing . I'm thinking I can connect one of these to air line from shop and start chasing the leak(s). 
 Any insight will be greatly appreciated , apologies for wordy description..
 Hope everyone is having a grand old time out there ,
Thanks ,
Chris
Chris, as you know, most of my experience is with 1990+ models so things could be different on your coach but here are a couple of thoughts. On the drain for the air tanks, on 1990's models, the wet tank is about the rear axle and the front and rear brake tanks are behind and way above the front axle, impossible to get to them without crawling completely under the coach (with the usual admonishment of never get under a coach that isn't well cribbed. If the system is depleted of air, you can remove the drain petcocks and either clean them or replace them. The air box drain, if unopened for a long time can be full of thick oil that will not come out. At least on my coach, the canister can be unscrewed and the entire canister dumped and wiped out. Old oil over time can be more like grease in consistency.

On the 120 v compressor, there is a dash switch to turn it off and one on most Newells I have seen. That switch is placed in different locations so you will have to look around for it. On many Newells, there is a fitting in the engine compartment that is set up to allow shop air to be attached. On mine it is near the rear of the coach on the passenger's side accessed by the side engine access door. I put a valve on mine because the fitting was leaking air. Of course I replaced the fitting also.

If you coach is leaning when the engine is not running and it is in travel mode, I would start with checking the travel height valve and solenoids related to the driver's rear air bag.
On both my 77 coach (not mine now) and my current 93 coach the air tanks sit between the frame members near the front and rear axles. They are cylindrical with domed ends and drains centered on the bottom. If I recall correctly the location on the 77 was with one near the front axle and two near the rear (the rearmost was the "supply" or wet tank). On the 93 coach the location is as mentioned above.

The 77 coach came to me with no drier, not a good idea if traveling in the winter. I installed a Bendix AD-9 and never saw water again at any of the drains. The 93 came to me with a finned CR Brakemaster dryer. I sometimes found a bit of water in the tank drains. I changed it to a AD-9 and have yet to find any liquids at the tank drains. Yes, this dryer requires changing the desiccant cartridge occasionally, but I would rather minimize the water in my air system.
To add to what those fine gentlemen have told you. Newell usually used round tanks for the wet tank and the primary and secondary brake tanks.

There are additional tanks welded as structures in the chassis members. You will notice the air bags tied into those square tanks. They also have drain plugs. Be acutely aware that if you drain the square tanks you will be exhausting all air from the suspension.
Thanks to your input I have located two air tanks , rear one has an automatic drain , front has a drain cock. Looking closer at the frame member tanks , I now see the air brake lines are coming to manifolds (?) , not going into the rectangular tank . It looks like the auto drain on rear tank is working as the outlet is clean .
I was thinking about a more modern air dryer , will look into that later on .
Two air bags per wheel at the rear , apparently.
Your help is greatly appreciated. I hope I can be of some help to you all in the future.
Chris
Your Pics hows an automatic moisture and contaminates drain.

see the example below:

http://www.plazafleetparts.com/uploads/2...lation.pdf

Tim