Read about the Great Fleets Across America
Subscribe

School Bus Fleet Magazine Forums
School Bus Fleet Magazine Forums
Home | Profile | Register | Active Topics | Members | Search | FAQ
 All Forums
 Professional Garage
 Enter Forum: Professional Garage
 C2 air dryer purging too often
 New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic  

buster133
Advanced Member

USA
409 Posts

Posted - 07/26/2013 :  09:12:51 AM  Show Profile  Reply with Quote
I have a 2013 6.7 ISB C2 wheelchair mini bus with hydraulic brakes, air parking brake and air ride suspension giving me issues. The air pressure gauge on this bus stays a little above 125 psi and the air dryer will purge itself about every six to eight seconds. When the bus is running and the parking brake is released, the pressure on the gauge only drops a touch below 125 and then builds right back up and starts purging again. Iíve checked all the lines in the immediate area around the dryer with soapy water and didnít find any leaks, Iíve also replaced the small ľ hose from the front of the compressor to the dryer because it had a slight kink, but that did nothing. Iím not that familiar with these setups because my fleet is 95% hydraulic brakes. The bus isnít losing any air pressure, it just seems like itís producing too much air and doesnít know what to do with it. Is there a new air dryer or governor in my future? The bus has only been in service for less than a year and has 14K on the odo. Any ideas, tips, suggestions? I hate to throw a bunch of new parts at such a new bus if itís something simple I havenít figured out yet.

C.HARDY
Advanced Member

350 Posts

Posted - 07/26/2013 :  10:16:21 AM  Show Profile  Click to see C.HARDY's MSN Messenger address  Reply with Quote
I would say a little trash in there would do the same thing but that bus is awful new to have that problem...

"Hardybusman"
Go to Top of Page

Bassman
Top Member

USA
510 Posts

Posted - 07/26/2013 :  12:23:20 PM  Show Profile  Reply with Quote
Try listening to when the compressor kicks in and then shutting the bus off and listen for a leak. If the line that runs from the compressor to the govornor (if you have a remote mounted govornor) is leaking, it will give this symptom. At least it does on my Mercedes buses. On the Mercedes, it is usually a leaking plastice 1/4 inch line running from the compressor to the gov. or the quick disconnect fitting on top of the compressor. Yours may be a different set up. Good Luck
Go to Top of Page

tigger2
Advanced Member

USA
281 Posts

Posted - 07/29/2013 :  04:44:04 AM  Show Profile  Reply with Quote
What make and modle of air drier do you have? Have you drained the air tanks especialy the wet or first tank in line from the compessor. Is the air governer mounting tight? You checked the lines what about the purge valve on the drier after the pop off some units purge the line air on the feed line but hold the governer pressure, is yours leaking it all off?
Go to Top of Page

ICFrank
Active Member

United States
27 Posts

Posted - 07/30/2013 :  07:27:17 AM  Show Profile  Visit ICFrank's Homepage  Reply with Quote
I agree with Bassman. I had a 2010 IC do the same thing. The line at the air compressor had a small leak. Repaired it and have had no further problems.
Go to Top of Page

buster133
Advanced Member

USA
409 Posts

Posted - 07/31/2013 :  03:02:11 AM  Show Profile  Reply with Quote
I had already replaced the ľ plastic line in hopes that it would have fixed the problem, but it didnít. This bus has the AD-9 dryer, and it doesnít have a wet tank, just a single primary tank. I didnít have any leaks that I could detect with soapy water and the bus wasnít losing any air, even overnight. Anyways, I picked up a reman bendix dryer and a governor, replaced them both at the same time while it was apart so I don't know if it was one or the other but the bus is functioning as it should, for now. Thanks guys

[URL=http://s7.photobucket.com/user/buster133/media/6f2e0703-1970-4ac9-bb1f-b6b9d7c12297_zps1741e113.jpg.html][/URL]
Go to Top of Page

Thomasbus24
Administrator

USA
3310 Posts

Posted - 08/01/2013 :  11:38:02 AM  Show Profile  Reply with Quote
Hang on to the AD9 and give it to your Thomas rep next time he is in. No reason you should have to pay for that. I'd put my money the check valve or the purge valve...both can cause that issue. AD9 is still the way to go though...good job to whoever spec'ed that particular item!
Go to Top of Page

Bus Tech II
Senior Member

100 Posts

Posted - 08/01/2013 :  11:43:15 AM  Show Profile  Visit Bus Tech II's Homepage  Reply with Quote
I have only seen this one time, and after fixing minor leaks, changing governor, the only thing that totally fixed it was replacing the whole dryer assy.
Go to Top of Page
  Previous Topic Topic Next Topic  
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
 


School Bus Fleet Magazine Forums © 2013 School Bus Fleet Magazine Go To Top Of Page
This page was generated in 0.14 seconds. Snitz Forums 2000