Air drier replacement or rebuild ?

[datrbone8]

I just had my 1998 Newmar DS in for an oil/filter change and chassis lube. The mechanic suggested the air drier should be replaced. Is it necessary to replace the entire unit or can the filter be replaced and the unit rebuilt with new parts? I think the new unit was around $ 380 and there may be a core credit for the old one (which makes me believe it can be rebuilt).

The thing is stuck way up in the frame and looks to be a PIA to remove in either case. Is it worth the time and trouble to rebuild (if possible) or should I just replace it ?

I'm pretty good with a wrench and I thought I might do the job myself. I haven't really taken a good look at it yet so any siggestions from experience would be appreciated.

[Skip426]

datrbone, have you downloaded the ,Air Dryer, service pdf from Freightliner web site, good info on filter replacement.
JMHO. With the low miles and run time an RV has compared to a truck, I can't see a reason to replace unless rust is an issue. If the dryer is currently functioning, I'd say filters only.
Take all safety precautions if you decide to DIY.

[datrbone8]

Thanks Skip. The coach has 88,000 miles but I saw no rust. It does seem to be working as there is evidence of purging out of the bottom valve.

It looks as though the drier needs to be dropped to replace the filter as doesn't seem to be room to spin it off and remove from the top.

I have the Freightliner info and I will read before attempting anything

Best regards

Larry

[Pigman1]

I've replaced filters on our previous 05 Diesel Bounder and the 08 Allegro Bus. Both sported Freightliner chassis. The filter kit was just less than $200 and it was a very easy job. Although many say they can do the job in the chassis I found dropping the drier and then replacing the filter a much easier job than changing it in place and trying to keep the dirt out. About an hour and a half and 15 minutes of that is cleaning the dirt and oil film that collects around it.

[Stillwater]

Do you have any way of determining who made the unit. There are several different kinds. Some are simple spin ons and cost about $ 35.00. Air dryers should be changed every couple of years otherwise if they are run until they become ineffective then you may start damaging other components of the air system. Just because it's purging doesn't mean that it is doing it's job.
http://www.bendixvrc.com/itemDisplay...ocumentID=2568

[lonestarace]

Originally Posted by datrbone8

I just had my 1998 Newmar DS in for an oil/filter change and chassis lube. The mechanic suggested the air drier should be replaced. Is it necessary to replace the entire unit or can the filter be replaced and the unit rebuilt with new parts? I think the new unit was around $ 380 and there may be a core credit for the old one (which makes me believe it can be rebuilt).

The thing is stuck way up in the frame and looks to be a PIA to remove in either case. Is it worth the time and trouble to rebuild (if possible) or should I just replace it ?

I'm pretty good with a wrench and I thought I might do the job myself. I haven't really taken a good look at it yet so any siggestions from experience would be appreciated.

We had a 98 DSDP on a Spartan chassis. It had a Midland Haldex Pure Air Plus dryer that I took off and rebuilt myself. There are two kits available to do a "complete" overhaul. The filter, pop-off, and purge valve kit is #DQ6026($120). The overhaul kit is #DQ6020($40). They both can be purchased at www.ryderfleetproducts.com or many other truck part places.

[Eagle123]

I just replace my air dryer cartridge. I got it from napa 27 bucks. I used a strap wrench and pipe to remove, since there was still air in the system. I just wanted to be far away when it let the air out. I started emptying air form the tank, but it was taking too long. I think they sell rebuilt kits for the assembly, I friend rebuilt his and not really a mechanic. Infact, he is missing a chromazone.lol No, he talks too much.

[Hooligan]

Larry; Not difficult. I've changed mine 3x (Freightliner XCS chassis) in place with room to work. Some are much easier when removed and done on the bench. Not much difference in time involved, Remove electrical harness (plug), the air lines and bracket. Even doing it in place, I had to unbolt from bracket to access fittings. Release ALL the air [pressure with the tank lanyards before you begin.....This may help: DiscoveryAirDryer

If 1st time it's being done I recommend the full kit (DQ6026), then in a couple years just change the cannister and the coalescing filter.

[datrbone8]

Thanks one and all for the information. I have the part number for the drier unit so I think I'll get the complete kit for it and give it a shot. I have no idea if or when the filter/dessicant was ever changed. Living in the desert it's unlikely I'll ever have a problem with condensation now that I know where the tank drains are. The unit is in a gravel storage lot which makes crawling around underneath a hassle. I'll drive it over to a friends shop where there is a nice paved area and have a go at it.

[wimberleyman]

Hooligan,

Many thanks for the download on air dryer maintenance. I've had a kit for almost 6 months but have held off doing the PM because I thought I would have to completely disconnect and remove the dryer. I just printed out the instructions which are much more simple than I thought and get on with it!

WM

[Gary RVRoamer]

"replace the air dryer" is usually just mechanic shorthand for "remove and replace the air dryer dessicant cartridge". I doubt if he intended that you should replace the entire unit.

[Stump Jumper]

I don't think that you will need to rebuild or replace the whole dryer unless your dryer is purging too frequently like mine was. If you do have to rebuild it, it isn't that bad but you would want to remove it. A simple dryer canister change is probably all that you need.

[wagonmaster2]

Has anyone with the Freightliner XC chassis had very much luck removing the air line to the air dryer that has the slip connection ( like a Chinese finger trap)? I can get the one off that screws on but the slip-joint one just will not slip so I've had to just support the dryer while I remove the 4 bolts that hold the top of the filter on. Really a pain to do it this way but definitely no room to get the top off/back on without getting dirt in it.

[Pigman1]

Originally Posted by wagonmaster2

Has anyone with the Freightliner XC chassis had very much luck removing the air line to the air dryer that has the slip connection ( like a Chinese finger trap)? I can get the one off that screws on but the slip-joint one just will not slip so I've had to just support the dryer while I remove the 4 bolts that hold the top of the filter on. Really a pain to do it this way but definitely no room to get the top off/back on without getting dirt in it.

Wagonmaster, I had the same problem the first time I pulled the drier off the Freightliner chassis. If you're aware of some of these facts, please forgive the repetition.

The fitting has 2 pieces that act as the gripper. There should be a groove in end of the fitting about 1/8" from the air hose. The groove needs to be as clean as you can make it all the way around. I use a very small screwdriver or pocket knife to clean the groove. The end of the fitting needs to be pushed back until the end piece fits tight against the body of the elbow. While you are pressing it back against it's inner spring evenly all the way around, the flex air line needs to be pushed in and held straight before the teeth holding it release. A slight twist also helps release the grip. As you can see a third and 4th hand would be very useful, but I found that when you actually get the drier loose from the Freightliner frame, you can get the tension off the air line and it's easier to hold it straight and push it in. I rested the drier on a small stool or booster after removing the frame bolts and it was easier to release the air line. After you get the line released, subsequent releases will be a lot easier.