Air Compressor PM

[Joe DeWeese]

     The air compressor on my 2006 Monterey is getting a little flaky (slow to build pressure, loses pressure quickly when shut off the engine).  Is there some preventative maintenance I should be doing to make sure the compressor is working right and the overall air system is okay??

[Joe DeWeese]

BTW, I read what little there is in the coach manual.  I also read the stream from 2018 on air compressor failing to build air and looked at the Bendix manual.  Nothing anywhere that helps me.  I'd hate to get caught somewhere with a failed compressor or air system

[Steve Huber Co-Admin]

Joe,
Consider checking the PSI output of the compressor. If it's OK, I'd next look for a leak since you state it was also losing pressure quicker than normal.
Steve

[Mike Shumack]

On preventative maintenance, you should change the "Air Dryer" cartridge/filter at least every two years.
Do you open the drain valves on your air tanks periodically to check for moisture?

[Joe DeWeese]

i guess I'm going to have to do some crawling around under my coach as I'm not sure where all of the components of the air system are located.  I understand that the compressor is on the engine and there are two tanks.  The diagram in the manual is very cryptic; doesn't show the connection to the parking brake or air brake system.  Also, no description of what the two pointers on the air gauge are for.  I assume one is for the brake system and the other for accessories, but that'd just a guess.  Is the air dryer near the engine?  Probably dependent on model and year of coach. 
Once the compressor gets going, it pumps up to full pressure (I eventually hear the air dryer purge) and holds pressure while driving. 
Thanks for your help
Joe D

[Joe DeWeese]

I'm looking on line for a replacement Desiccant Cartridge for the Wabco-R950011.  There are a number of brands and prices from $35 to $60.  Is there a preferred one?  Any brands I should avoid?

Thanks again,

[Mike Shumack]

Also, no description of what the two pointers on the air gauge are for.  I assume one is for the brake system and the other for accessories, but that'd just a guess.  Is the air dryer near the engine? 
Joe D

The air dryer is near the air compressor (at the rear of coach). It would be within 2 feet of the compressor. I would get the "genuine" Wabco filter. I got mine on Amazon, but be aware if the price is too good ...  Also, if you are going to change it yourself you will need a large filter/strap wrench (about a 5-1/2" capacity).

On the dash air gauge - the reason there are two pointers is because air brake systems have "two separate systems" (a primary and secondary brake system, just like a hydraulic brake system) so if air pressure is lost to the primary side (for example), the secondary air system can stop the vehicle, and vise-versa.

Typically the primary side is shown as "green" (and primary for the rear brakes which does the majority of the stopping) and the secondary side gauge/pointer is red/orange. But there is no requirement that be that way.

Here's a diagram of a typical air brake system (this one is for a semi-truck, but the majority of it is correct for a motor Coach too.

[Joel Ashley]

Cartridge location: 06 Monterey battery bay, far left side.

This is the one Henderson’s put on mine:

https://www.haldex.com/en/na/air-dryerair-line/air-dryers/competitive-newremanufactured/competitive-cartridges/950011k/

Joel

[Joe DeWeese]

Thanks Joel and Mike, your replies and information are very helpful.  I know exactly where the dryer is located on my Monterey.  I saw a number of cartridges on Amazon so I will order one that is Wabco.  Before I tackle trying to replace it I'll locate a 5 1/2" filter strap.  Also, Joel, the diagram you included provides the level of detail I am looking for.
Thanks again, guys,
Joe D.

[Joel Ashley]

Glad we were of some help, Joe.  I only regret that the diagram copy I have isn’t higher resolution.  Zooming in can help, but if you can’t make some of the writing out, let me know;  taking a photo of fuzzy text doesn’t help it. 

The Haldex cartridge is a good brand, commonly used by BAC supporter, Henderson’s Line Up.  If you order from Amazon, that’s fine per getting the best price;  just be sure it is a reputable brand.  I’m not sure in this case I’d necessarily trust Amazon reviews, and on these coaches going cheap on parts is not advisable.  It’s like our mantra to use only CAT filters and parts on our CAT engine systems.

I did think from one of your posts that you’d finally spotted the dessicator, but I included the photo just in case.  The filter doesn’t require it, but if you’re going to check other components under the rig, be sure you block the frame strongly, or put the tires on ramps, especially when messing with air devices. 

Joel

[Steve Huber Co-Admin]

Joe, Joel,
There is a pdf version of the 06 Monterey owners manual in Coach Assist.
Steve

[Fred Brooks]

     Sure is a lot easier to remove once you drain all the air out out of the tanks! Fred