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Motorhead-54 · 02-02-2020, 09:27 AM

A couple of posts earlier I mentioned finding a leaky pneumatic fitting up front on the cross member and I always like to follow up with my results/findings. Swapping that fitting was pretty straightforward after securing the coach and dumping the air from the system. For those that might be curious, the fitting was a “Parker Hannifin 369PTC-6-6” swivel elbow. 3/8” NPT threads on one end and 3/8” Nylon push-to-connect on the other....picture below.

With that leak fixed I took the opportunity to check every pneumatic fitting I could find from front to rear using a bottle of soapy water. I did not find another leak anywhere bottomside!

But.....the last place I went to check was the WABCO air dryer purge valve which is a common leak spot. The purge valve showed no signs of a leak. My last check before buttoning things up and calling it a day was to spritz the three air line connections on the dryer....no leaks found. What I did find leaking though is the diaphragm on the regeneration valve assembly of the dryer. Looks easy enough to swap out, just four metric allen bolts to disassemble it and about a $25 parts kit.

Hopefully this is my last post on this thread.

brobox · 02-02-2020, 12:29 PM

Great report and follow up. Really enjoyed the sharing.

Motorhead-54 · 02-02-2020, 02:45 PM

Quote:

Originally Posted by brobox

Great report and follow up. Really enjoyed the sharing.

Thanks. I always assume that I am not likely to be the first person to experience some of these issues. Fixing a leak like the one at the dryer should be within just about anyone’s skillset needing nothing more than a 5mm allen wrench to disassemble. It was certainly easy to diagnose with just a squirt bottle full of soapy water! I’d bet there are others on the forum with this very same leak.

IF I had taken it to a heavy duty truck repair shop, I would have had to schedule an appointment, drive 15 miles to drop it off, get a ride home, wait for their schedule to “fit me in” and be prepared for the $150.00 per hour shop rate plus $25.00 per hour premium because it is an RV. Plus I’d be hoping they diagnose it properly and of course they’d likely choose to replace the entire dryer ( $$ ) vs install a $25 repair kit. That evolution would likely consume a week or more which means I’d have to unload the fridge because there is about zero chance that I could count on them keeping it plugged in for me.

Yep, I do all my maintenance when I can. The shop rate is affordable, the schedule is perfect, all done at my convenience, and I know who to complain to if something isn’t done right! Plus, I like to tinker.

757driver · 02-02-2020, 02:59 PM

Great write up. Thanks for the detailed information.

MRUSA14 · 02-02-2020, 03:41 PM

Quote:

Originally Posted by Motorhead-54

IF I had taken it to a heavy duty truck repair shop, I would have had to schedule an appointment, drive 15 miles to drop it off, get a ride home, wait for their schedule to “fit me in” and be prepared for the $150.00 per hour shop rate plus $25.00 per hour premium because it is an RV. Plus I’d be hoping they diagnose it properly and of course they’d likely choose to replace the entire dryer ( $$ ) vs install a $25 repair kit. That evolution would likely consume a week or more which means I’d have to unload the fridge because there is about zero chance that I could count on them keeping it plugged in for me.

How about the part where they say your drier assembly has a crack in it (that they caused by over tightening), and that will be another $450? Or the part where you get it home and it is still leaking so you have to take it back and start the whole rigmarole again?

Yes, you are MUCH better off if you can fix it yourself.

Magic-carpet · 02-03-2020, 07:10 AM

Quote:

Originally Posted by Fattman-Litlboy

We had the same problem, until Spartan corrected our method of parking. If you back your coach into the parking area, and shut off the engine, you may be causing the problem. Once you back into position, shift to neutral and then into drive and drive forward about 1-ft. Then shut the system down. That resolved my issues.
Jim

Quote:

Originally Posted by 757driver

Jim,

I don’t see it. How does this affect airing up after being parked for a while, did Spartan say?

Don, I think the problem is if you back in with the tag dump valve set to on/auto, then stop without moving forward again, you leave the tag dump valve open. If you then start the coach with that tag dump open, it will hinder your airing up correctly. If you put the coach in drive and pull just a bit forward, you close that valve.

757driver · 02-03-2020, 11:19 AM

Quote:

Originally Posted by Magic-carpet

Don, I think the problem is if you back in with the tag dump valve set to on/auto, then stop without moving forward again, you leave the tag dump valve open. If you then start the coach with that tag dump open, it will hinder your airing up correctly. If you put the coach in drive and pull just a bit forward, you close that valve.

Jeanne,

Ahhh, that makes sense. Mine does not have the newer tag dump switch so when I select neutral it closes.

dennis45 · 02-03-2020, 11:56 AM

If your symptom should reappear, you might want to investigate the possibility of the air compressor not building air when its cold.
I went around the horn with a similar problem on my old Dutchstar years ago. In the end, it came down to carbon build up in the compressor cylinder head which effected the loading/unloading to the air compressor.
The shop that was working on it tried to convince me the air compressor had to be replaced (75,000 Miles) so i said, if that’s the case I don't mind spending the $3000 to replace it but if not, you can refund my $3000.
Finally, a young mechanic did some investigation with Cummings and found this bulletin. They did this procedure and fixed the problem. Total cost under $800.
Motorhomes are particularly effected by this condition because of short trips as opposed to a highway truck that operates long hours at a time.

Motorhead-54 · 02-03-2020, 07:43 PM

Quote:

Originally Posted by dennis45

If your symptom should reappear, you might want to investigate the possibility of the air compressor not building air when its cold.
I went around the horn with a similar problem on my old Dutchstar years ago. In the end, it came down to carbon build up in the compressor cylinder head which effected the loading/unloading to the air compressor.
The shop that was working on it tried to convince me the air compressor had to be replaced (75,000 Miles) so i said, if that’s the case I don't mind spending the $3000 to replace it but if not, you can refund my $3000.
Finally, a young mechanic did some investigation with Cummings and found this bulletin. They did this procedure and fixed the problem. Total cost under $800.
Motorhomes are particularly effected by this condition because of short trips as opposed to a highway truck that operates long hours at a time.

Thanks much! I will file that information away for future reference.

Motorhead-54 · 02-12-2020, 05:10 PM

Yet another followup...I received the diaphragm for the air dryer’s leaking regeneration valve today. It was pretty easy to swap. The only tool required was a 5mm allen wrench and a couple of nimble fingers. I did find some corrosion on the mating surfaces of the two halves so I may not end up with a completely airtight seal. The old diaphragm I pulled was not at all pliable.

Also noticed an occasional soap bubble on the blowoff valve so ordered that kit today. I am pretty sure I can swap it out without removing the dryer from the coach. The only tool needed will be a set of c-clip pliers.

And while in the bay I replaced the large desiccant filter. The old one was slightly over two years old and due.

Motorhead-54 · 02-14-2020, 03:08 PM

I just finished up the dryer purge valve rebuild. It is a simple enough task to swap out the old for new pieces but after fighting with the large snap ring/c-clip for nearly an hour I finally gave up and just removed the entire dryer from the coach to finish the job. Getting that snap ring back in its locking groove is just too hard to do with the limited amount of space you have to work in when the dryer is mounted to the coach.

You remove two large air lines (forward and return) plus a small push to connect air line and then one quick disconnect electrical connection. Three bolts hold the dryer to the coach and having the dryer on the workbench makes the snap ring install a no-brainer.