Air Dryer Service

[FIRE UP]

Originally Posted by ftodaro

My coach also has the Pure Air plus dryer. I serviced it my self 3 years ago. I am thinking about replacing the entire dryer this time. I am told that the entire dryer is not that much more than the filter service kit.



I know when i did my three years ago, there was a lot of gunk on the out side of the filters. you cannot get much of it out without contaminating the system. My unit is now 18 years old so I may go with new replacement.

ftodaro,
Take a look at these links, then determine whether or not the kit, is your next choice, as opposed to the entire unit.
Scott

https://www.finditparts.com/products...hoC98gQAvD_BwE

https://www.finditparts.com/products...RoCF0MQAvD_BwE

https://www.ebay.com/itm/HALDEX-DA33...frcectupt=true

[jelag]

One parting thought... the air system can and will fail in freezing weather due to moisture/vapor collecting on the various valves in the air brake system... any of these valves uses small porting air to open and close valves... air pressure from either the emergency brake push/pull switch, or throttled air from the foot pedal doesn't nothing more than apply a small amount of air pressure to these valves...


Each valve has what is called a crack pressure, or the pressure required to open the valve... in most common air brake applications to slow a vehicle the foot pedal might only send 12 to 20 lbs of air pressure to each valve and they crack open based on this pressure.. In most stops, there is relative low air pressure in the spring brakes to activate the brake shoes...


This low pressure across these valves can freeze with moisture... so the primary purpose of the air dryer is to filter out the water... in some HEAVY MOIST CLIMATES where freezing is a constant problem, that can add an alcohol treatment to the system to melt and allow the air to pass through the valves...



On the trucks I owned we serviced the air dryers going into winter when we checked the antifreeze and other items on our winter check list...



Hope this helps for better understanding of the system

[veraken]

If you have a Wabco unit, do a search for Wabco in the Files section above. I uploaded a copy of the Service Manual (too big to add to this thread) and it will tell you all the info you need.

[ftodaro]

Originally Posted by FIRE UP

ftodaro,
Take a look at these links, then determine whether or not the kit, is your next choice, as opposed to the entire unit.
Scott

https://www.finditparts.com/products...hoC98gQAvD_BwE

https://www.finditparts.com/products...RoCF0MQAvD_BwE

https://www.ebay.com/itm/HALDEX-DA33...frcectupt=true

Scott thanks for those links. Let me ask two questions.
You and i have the same unit, so I assume you are pretty confident the DA33100X is the correct replacement?
Next, When you took yours apart did you find lots of gunk inside the the dirty side filter area? Did you clean that out. Freightlinger told me not to clean it with solvent?
That was my thinking about at some point just replacing it.

Frank.

[Ray,IN]

Originally Posted by jelag

One parting thought... the air system can and will fail in freezing weather due to moisture/vapor collecting on the various valves in the air brake system... any of these valves uses small porting air to open and close valves... air pressure from either the emergency brake push/pull switch, or throttled air from the foot pedal doesn't nothing more than apply a small amount of air pressure to these valves...


Each valve has what is called a crack pressure, or the pressure required to open the valve... in most common air brake applications to slow a vehicle the foot pedal might only send 12 to 20 lbs of air pressure to each valve and they crack open based on this pressure.. In most stops, there is relative low air pressure in the spring brakes to activate the brake shoes...


This low pressure across these valves can freeze with moisture... so the primary purpose of the air dryer is to filter out the water... in some HEAVY MOIST CLIMATES where freezing is a constant problem, that can add an alcohol treatment to the system to melt and allow the air to pass through the valves...



On the trucks I owned we serviced the air dryers going into winter when we checked the antifreeze and other items on our winter check list...



Hope this helps for better understanding of the system

Service brakes do not use the spring brakes (parking/emergency brake), two separate systems. Rear air canisters have two sections, front one section.

[jacknife]

It is usually a spin on filter . Simple to put on ,just like an oil filter. Make sure your air pressure is zero . Put oil on gasket so it will come off hand tighten. Always from some air out of your tanks daily. Owned Big rigs and changed annually, of course that was at least a 100, 000 miles later.

[FIRE UP]

Originally Posted by ftodaro

Scott thanks for those links. Let me ask two questions.
You and i have the same unit, so I assume you are pretty confident the DA33100X is the correct replacement?
Next, When you took yours apart did you find lots of gunk inside the the dirty side filter area? Did you clean that out. Freightlinger told me not to clean it with solvent?
That was my thinking about at some point just replacing it.

Frank.

Hey Frank,
Based on that picture alone, yes it looks like the correct replacement unit for our coaches. However, if I was getting serious about doing it, I’d match up all the numbers I could, on both units, before pulling the trigger. As for whatever kind of junk there might have been in mine when I got it apart, first off, that was quite a while ago. Second, if there was gunk in there, and it was anywhere near gooey or greasy, yep, it got the solvent treatment.
I might understand why Freightliner would not want solvent being used. Maybe it’s because the average DIY type backyard mechanic might not take ALL precautions to remove any and all residue from that kind of cleaning agent. And, if any remained in that unit, and it was reassembled, you’d have an immediate contaminated system. NOT GOOD!

So, as usual in this kind of scenario, I probably used solvent then, I rinsed the unit with Lacquer thinner or Acitone, to completely rid the unit of any solvent residue. So far, after installing that DQ (no, not Dairy Queen) 6026 kit, a good couple years and about 8,000 - 10,000 miles ago, I must have done something right ‘cause the big girl still runs down the road with no apparent air system issues.
Scott

[barmcd]

Originally Posted by ftodaro

Scott thanks for those links. Let me ask two questions.
You and i have the same unit, so I assume you are pretty confident the DA33100X is the correct replacement?
Next, When you took yours apart did you find lots of gunk inside the the dirty side filter area? Did you clean that out. Freightlinger told me not to clean it with solvent?
That was my thinking about at some point just replacing it.

Frank.

Mine had gunk in it under the spin on desiccant cartridge. Used a hanger and rags to clean that gunk out. I bent the hanger to grab the rag and bunched the rag up around the end and used it to swab out the chamber below the desiccant cartridge. You can remove the turbo saver valve and clean it out from the side too. The passage goes all the way across the dryer. Here's a good picture of what one looks like inside.

[ftodaro]

Originally Posted by FIRE UP

Hey Frank,
Based on that picture alone, yes it looks like the correct replacement unit for our coaches. However, if I was getting serious about doing it, I’d match up all the numbers I could, on both units, before pulling the trigger. As for whatever kind of junk there might have been in mine when I got it apart, first off, that was quite a while ago. Second, if there was gunk in there, and it was anywhere near gooey or greasy, yep, it got the solvent treatment.
I might understand why Freightliner would not want solvent being used. Maybe it’s because the average DIY type backyard mechanic might not take ALL precautions to remove any and all residue from that kind of cleaning agent. And, if any remained in that unit, and it was reassembled, you’d have an immediate contaminated system. NOT GOOD!

So, as usual in this kind of scenario, I probably used solvent then, I rinsed the unit with Lacquer thinner or Acitone, to completely rid the unit of any solvent residue. So far, after installing that DQ (no, not Dairy Queen) 6026 kit, a good couple years and about 8,000 - 10,000 miles ago, I must have done something right ‘cause the big girl still runs down the road with no apparent air system issues.
Scott

Got it. Yes i like to do all my own work and get quite a bit of satisfaction out of doing it. I will admit when i first bought this coach i was intimidated by it as I had no prior experience with Truck or motor home repair, but its really no different than any other mechanical repairs. Plus, just about any project is on the internet some place.

Did i say, thank God for the internet. 15 years ago we would not be doing half the stuff we can do today, or at least without making a mistake.

I will call FL get a price and part number i will send you a pm with it. I may just do what you did and clean it well.