Go Back   iRV2 Forums > MOTORHOME FORUMS > Class A Motorhome Discussions
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
Thread Tools Search this Thread Display Modes
Old 01-01-2016, 10:24 AM   #15
Senior Member
Join Date: Jul 2014
Posts: 5,481

Lots of experance in air brakes tells me the same thing.

The only exception is that some accessories ( air ride, horn, air seat ) run off a regulator, set to stop flow at around 60 lbs, to save the air for the brakes.

Even with that, it would need to be a big leak, to not climb above 75 lbs even at high engine speed.

It would also slow down the air buildup and never get to the air dryer purge pressure or cycling constantly.

twinboat is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 01-01-2016, 10:39 PM   #16
Junior Member
sejac55's Avatar
Join Date: Dec 2015
Location: South Jersey
Posts: 13
I hope that we will hear what the issue was when it is diagnosed and repaired.

sejac55 is offline   Reply With Quote
Old 01-02-2016, 04:59 AM   #17
Flyerpicker's Avatar
National RV Owners Club
Newmar Owners Club
Join Date: Dec 2010
Posts: 41
Originally Posted by dpinvidic View Post
Curious why folks suspect the dryer.
The wet tank is in front of the dryer, and the pri & 2nd tank are fed by the wet tank.
If the pri tank shows 120psi, that proves the dryer is ok and the wet tank must have 120psi.

In thinking about this more, it is not likely to be a leak, if it was leaking bad enough to prevent reaching 120, it would certainly drop to zero right after the engine was turned off.

A restriction would not prevent reaching 120, it would just take longer than the other tank.

It really sounds more like a sensor problem which could affect both the gauge and the alarm.

The OP really needs to put another gauge on the system to confirm the actual pressure before buying parts and guessing.

Just the opinion of an arm chair quarterback


Hi Dan,

I tend to agree with you, for all the reasons you mention. The ONLY thing about the entire system that is non-normal is the low reading on the rear tank. It fills, burps, responds to pedal applications, alarm status due to <65psi, etc.

One thing i have learned from this post is that some responses "attacked" me for placing lives in jeopardy bla bla..... As a recently retired captain for a major airline, I made decisions for decades that determined a real problem or a gauge, and I would like to assure them that I would never consider going without full brakes. But in an ideal world, both gauges would read identically. (I have also seen gauges that indicated a perfectly normal condition for a completely inoperative system)

And so now, I will research the sensor by verifying the actual system pressure.

Carolyn, Jim, and Clara Allen
'05 Newmar Dutch Star
Fisherville, KY
Flyerpicker is offline   Reply With Quote
Old 01-02-2016, 08:08 AM   #18
Senior Member
Tiffin Owners Club
Freightliner Owners Club
Join Date: Aug 2014
Posts: 1,671
Hi Jim,

Good to hear your on the right track. We are thinking that the actual pressure is good.

Here us a typical pressure warning switch.
60 psi switch

Looks like you have a Spartan chassis. Maybe someone can tell you exactly where that switch is.

My first guess would be that the warning switch and the gauge sensor are two different things. But this assumption is contradicted by the fact that a single breaking event caused the alarm. The odds are against two components being bad. So this suggests that you may have a pressure transducer which is used to drive the gauge, and trigger the alarm.

The first order of business would be to determine if this is true for your chassis.


2014 40QBH Phaeton DP Cummins 380HP ISL, Freightliner XC, 2014 Jeep Trailhawk TOAD
Blue Ox Aventa tow bar, SMI Air Force One -South Orange County Ca.
dpinvidic is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
2002 MADP Air leak Spk64 Newmar Owner's Forum 5 07-13-2015 04:55 AM
Freightliner chassis M2 Biz class truck/RV No rear AIR Bag AIR ! Chatham Freightliner Motorhome Chassis Forum 4 06-26-2015 06:18 AM
Air Con Question Jchet 5th Wheel Discussion 3 05-11-2015 06:49 PM
Air Bag Valving Leaking? customfab iRV2.com General Discussion 3 09-24-2014 07:28 AM
Fill air tanks by alternate means Terry W. Fleetwood Products Owner's Forum 1 07-05-2014 02:13 PM

» Virginia Campgrounds

Reviews provided by

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 02:25 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.