Meritor Tire Inflation System on Wabash trailers

Your explanation is excellent. Mostly because it enumerates the several pitfalls of the system. Asking a driver to be this knowledgeable about a system like this is just like asking him to troubleshoot several other systems on a tractor trailer. None of it is going to happen in the real world. The only thing he is supposed to do is see that the tires are properly inflated. Unfortunately, there is no way to check the inflation on an individual tire unless you disassemble the system, which if I am head of maintenance, I don't want a driver to do.
The original reason for the on board inflation systems was because
1. The drivers weren't even thumping the tires on a pretrip
2. The maintenance dept/system user of the trailer either wasn't checking tire pressures or didn't have a systematic timely method for doing so.

So, on board systems become a "sales point" and another $1000 option gets put on a trailer that is ineffective because of the lack of training/maintenance in the real world. But worse, because the decals are there, it gives a false sense of security to drivers, maintenance and the inspectors at the scales

We haul new trailers with this option all the time, and we also haul older trailers with this option. The older trailers (5-10 years old) have in the vast majority of cases had the system disabled, because it wasn't being used or maintained properly, and simply didn't work. Ask any tire repair joint how they like dealing with the things...

 

iv got a air inflation system on one of my trailers. it will keep up with a decent size puncture. I haven't had one yet that the system couldn't keep aired up rolling down the road. a real slow leak sometimes the sensor wont pick it up until air has been cut off and the tire has had some time to leak down a bit and then the light will flash for a bit while it is airing up and then shut off.

a couple easy ways to identify witch tire is leaking when you have a real slow leak. spray bottle of soapy water and spray the tires and look for bubbles. or let the truck sit over night with the air cut to the trailer and then gauge the tires and see witch one is lower than the others. (this is the method i normally use) and if the leak is slow enough that you have to use a gauge rather than a thumper to figure out witch tire is leaking i will just wait till its convenient to patch the tire.

I haven't had any issues with the air lines or hub lines leaking. but like anything it will eventually need maintenance. I have had a tire shop break off one of the air line fittings putting the rim back on the hub.

to me the benefits outweigh the negatives and feel it was money well spent on the inflation system. i just wish i could have it on my tractor as well. I have had the system on my trailer for probably approx 2 years

 

Please refer to the following - http://psi-atis.com/Documents/D01.pdf



I work for the design and manufacturing company that makes the MTIS product, Pressure Systems International based in San Antonio, TX (www.psi-atis.com). I wanted to add some comments in hopes that it further explains some of the questions below.


In general, approximately 50% of all new trailers are now being made with automatic tire inflation (ATIS). While there are other suppliers out there, MTIS by PSI is the clear market leader, and has been around for 21 years (more than any other supplier). Typically, fleets get their investment back within (1) year, through fuel savings, tire life improvement, labor savings and roadside call avoidance (since it can keep a tire inflated with small punctures/leaks).


First thing is make sure that if you have issues with your ATIS, make sure that you know which one you have, by looking at the control box. It is common for fleets to assume that they are using ours, since we are the most widely accepted.


The following comments are specific to MTIS by PSI;


It is always a good idea to do a pre-check, whenever taking possession of a new trailer, and as previously mentioned, a simple visual check of the system on-off valve at the inlet side of the control box to ensure that it is turned on. While it is infrequent, on occasion, some trailers may leave the plant with the system on (regardless of the trailer manufacturer).


1. We put a decal on the inside and outside of the box that indicates what the tire pressure setting is (e.g. 95 PSI).


2. The regulator is set to 3 PSI above the tire setting. This is because the tire hoses have valves with a 3 PSI crack pressure. Therefore in order to get 95 PSI into the tire, the regulator is set to 98 PSI.


3. There is a pressure protection valve (PPV) mounted on the air tank, that makes sure that your air brakes have priority. Once the air reaches the minimum pressure, the PPV will allow air pressure to flow though the control box.


4. The system ensures that your tires are at a minimum level. It will not deflate your tires, as tires are designed to run above the cold pressure.


5. It is very easy to check the tire pressure, should you need to do so, by removing the hose at the cap. Typically, no tools are required, as the knurled fittings will allow themselves to be removed by hand. A check valve will close the supply at the hub cap at that point, so you do not need to turn off the system. Then, simply use a calibrated gauge at the hose end to check tire pressure. Be sure to properly tighten the hose back to the cap connection.


For more detailed information, please visit the Meritor website (www.Meritor.com) and go to the customer center to download the Maintenance Manual (MM-14P) for detailed procedures.


Please feel free to also visit the PSI website and contact any of our team members listed under the contact list.


I hope this helps!

 

I found the easiest way was to put an air pressure gauge in-line off the control box. Quick glance will show if a tire or line is leaking, then go on to check individual tires.

 

As is touched on in post #7. Is there a way to test the light while parked to insure the light (and it's supporting system) is functioning properly? (Besides puncturing a tire)

It looks like it would illuminate momentarily as soon as power is supplied to the ABS system to indicate the light is at least working when called for.

 

I was told, that one of my hubs are leaking and they (shop) simply disconnected all air hoses and shut the system off.
Question, how much does it cost to fix it, approximately?
Anyone, anyone... Bueller?