View Full Version : Haldrex air dryer filter

01-20-2011, 11:50 PM
How big of a job is changing the filter on a Haldrex air dryer. I need to get it done on my coach. Do I have to bring the whole thing down and do all the work on it on a work bench or do I just take the bolts off the bottom of the filter and then unscrew it with a big strap wrench? I need some advise.

01-31-2011, 08:30 PM
I suggest you go to the Haldex website...www.haldex.com where you will find downloadable pdf. maintenance/repair instructions etc., It's a little too complex to explain here. Very good website help though! Good Luck from England! javascript:emoticon(':D')

02-02-2011, 11:52 AM

I'm not that much of a mechanic and I was able to do it. Do as ummalterman suggested and download the instructions. I got the part at NAPA. No big deal!

02-04-2011, 09:46 PM
I called Freightliner in Las Vegas and asked them if they had the parts available if I took my coach down there to change the filter. The shop foreman that is in charge of the motorhome area asked me how many miles I had on the coach and he asked if I drove where it rains a lot. I told him most of my driving was in dry climates. He said not to worry about changing the filter if the dryer is working proper. He said to change it if it starts purging repeatedly. If it just lets out a big blast of air after you charge the reservoirs and not again, he said not to worry about working on the air dryer. So I will extend my filter change. :D

02-04-2011, 10:31 PM
Thanks, RayChez! your last posting has just answered a query I had on this forum months ago. My air pressure (rear gauge) had been dropping to around 65psi then back up to 130psi in a constant cycle, I discovered it was the Haldex blowing off then leaking down to 65psi following an alarming ride out, on very narrow (hedges brushing both sides!) British country lanes, I had a sweat on because I believed the air brakes would, of course, come on when the pressure goes, we would have been stranded very dangerously on roads with tight bends, and not much wider than the coach!

I was so relieved when it stopped dropping at 65psi.-I've not had a definitive answer to my "Is this normal?" question before, so if an experienced RV garage foreman says change the filter..there's my answer! Many thanks. This forum is like a lifeline to me, there's relatively little info. on RV's here in England. :?

1997 32' Sunvoyager DP(extensively modified!)
Spartan chassis. Cummins 275hp.