While I have the muffler system out to replace with a resonator I did the air dryer service kit thing. I sure would have hated doing it with the side panel on and muffler in place. Still not a fun job. The service kit was $128.85, part DQ6026 (Haldex). It consisted of the desiccant canister, the coalescing filter, a new purge shield, and pressure relief valve assembly. Tools needed - 11/16 combination wrench for the pressure relief valve, 5/16 allen wrench (must be an L shaped one)for the drain plugs on the bottom, 5/16 wrench, (also a 5/16 nut driver made it easier, these are for the 3 screws that hold on the purge shield), a 9/16 combination wrench and a 1/2 inch socket/ratchet if you have to pull the whole assembly loose to get at the relief valve. I had to on mine. Also a strap filter wrench to get the old canister off and some pipe sealant for the drain plugs. I also needed a 1 1/8 inch wrench to move an air hose that wouldn't let the purge shield drop off.
The instructions were excellent so it was just a matter of getting under there and getting dirty. If I had it to do over, I wouldn't remove the canister until the last thing to keep from getting dirt inside, or at least cover it. One confusing thing, there was an o ring on the canister mounting nipple that it instructs to remove and throw, but no new o ring with the kit. I assume it must not be needed. (there is a new o ring for the coalescing filter) The purge shield was the trickiest part, it holds in the heater, plus there's a new gasket that just lays on top of the shield while you try to balance all that and the retaining ring and get it up and screwed into place without knocking to much dirt in your face. The old setup didn't have the gasket so it's either a new item or the previous replacement job just left it out.
Meant to add, the place I got the parts was very surprised that they were for a MH, said they don't usually have dryers.
I just had this dryer serviced here at FOT. Steve showed me how to do it. They only change the spin on filter, the coalescing filter, and the pressure relief valve. He did remove the large air line to give better access to the pressure relief valve. His big CAUTION was in removing the pressure relief valve. Apparently it is not uncommon for it to break leaving the threads in the housing! Don't over tighten. Ours was no problem.
Maybe his BIGGEST CAUTION was to de-pressurize the system! In fact, he said you probably can't get the black spin off cannister off with the system pressurized.
I had mine serviced at FOT a few weeks back and wanted to see how it was done as well. I was told the same thing, the pressure relief valve can snap off and turn a 1 hour job into an 8 hr job. The tech said it can make for a bad day.
And before Michelle tells on me ... Yes I've personally broken off that pressure relief valve during one of my air dryer maintenance days >:( and yes it does twist right off if over tightened (and we are not talking about a lot of torque here)
I had to completely remove the air dryer from the coach so I could get an easy out on the broken threads. Then when I was still unable to extract it, I took the unit to a truck service place, who also failed in their attempt to remove it. The third place, truck service / machine shop, was able to extract the broken off chunk ^.^d
So I'd agree with a simple 1hr task turning in to an 8 hour event ....
Breaking the PRV is a good reason to service the air dryer regularly. Oftentimes the PRV is skipped because of the challenges involved. That just makes it more likely that a problem occurs in the future.
For several years, we used Foretravel service to change our air dryer filters. Each time the tech only changed the large filter and the coalescent filter. And they threw away the new brass pressure relief valve in the package. When I ask why they did not change our pressure relief valve, I heard it was hard to reach, the new ones were crap and did not work, so it was better to keep the older one and it was not needed to be changed. The techs did have a ground down wrench to help get the pressure relief valve off if they wanted.
x 2 on the getting all the air out first. I hadn't had rig running for a month so assumed all the air would be out. As it turned out, there wasn't much, but enough that the canister wouldn't budge.
Just got a call from a fellow foretravel owner broke down in the Crockett Tx area. The haldex system seems to be malfunctioning. Needs part numbers for whole unit and advice. He has a 95 320 40ft. call me 806 799 4735 thanks jc