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Chickadee · 10-15-2008, 03:53 AM

G'morning NEWMAR Gang! Say,...got a question for you experienced mechanic type folks. We run an 08 Essex 4502 which has the Smart Tire tire monitoring system installed. While at Nappanee a few weeks ago getting things tweaked, we finally had them show us how to set up the Smart Tire system and got it all working (both front tires, inside and outside duals, and the tags). Well, anyway, after departing Newmar heading South we ran over (unavoidably) one of those highway tire debris "gators". I managed to straddle this gator for the most part but it did end up causing our "Newmar" mud flap some damage, and it evidentally cracked some molding behind the license plate on our toad. After removing mud flap etc., we DID get to Kentucky Horse Camp N. of Lexington and a week later drove further S. to Adairsville, GA on I-75 for an overnight before cutting East across Georgia over to the Cleveland/Helen area just N. of Gainsville which was only about a 100 mile run. About 15 miles short of our destination at Cleveland, the Smart Tire alarm came on indicating high temp first on left inside dual, then switching to right inside dual and a bit later back to left inside dual...etc. We pulled over to let em cool and pick up some grocerys then proceeded to campground where we'll be for a couple of weeks. Now....that little 100 mile run was over twisty, turny, hilly country and I did need to use my svc. brakes quite a bit so we figured the alarm might be due to this braking..HOWEVER, as I sit worrying about this kinda stuff, I'm wondering whether that gator could have, or might have done something to the brake line (don't even know if there is such a thing) or might be the cause of this inside dual overheating thing. DOES ANYONE have input regarding what I might check??? Can't eyeball anything wrong under rear axel but haven't been thorough cause I don't know what to look for. Thanks. Steve

Chickadee · 10-15-2008, 03:53 AM

G'morning NEWMAR Gang! Say,...got a question for you experienced mechanic type folks. We run an 08 Essex 4502 which has the Smart Tire tire monitoring system installed. While at Nappanee a few weeks ago getting things tweaked, we finally had them show us how to set up the Smart Tire system and got it all working (both front tires, inside and outside duals, and the tags). Well, anyway, after departing Newmar heading South we ran over (unavoidably) one of those highway tire debris "gators". I managed to straddle this gator for the most part but it did end up causing our "Newmar" mud flap some damage, and it evidentally cracked some molding behind the license plate on our toad. After removing mud flap etc., we DID get to Kentucky Horse Camp N. of Lexington and a week later drove further S. to Adairsville, GA on I-75 for an overnight before cutting East across Georgia over to the Cleveland/Helen area just N. of Gainsville which was only about a 100 mile run. About 15 miles short of our destination at Cleveland, the Smart Tire alarm came on indicating high temp first on left inside dual, then switching to right inside dual and a bit later back to left inside dual...etc. We pulled over to let em cool and pick up some grocerys then proceeded to campground where we'll be for a couple of weeks. Now....that little 100 mile run was over twisty, turny, hilly country and I did need to use my svc. brakes quite a bit so we figured the alarm might be due to this braking..HOWEVER, as I sit worrying about this kinda stuff, I'm wondering whether that gator could have, or might have done something to the brake line (don't even know if there is such a thing) or might be the cause of this inside dual overheating thing. DOES ANYONE have input regarding what I might check??? Can't eyeball anything wrong under rear axel but haven't been thorough cause I don't know what to look for. Thanks. Steve

rebelsbeach · 10-15-2008, 04:02 AM

I don't have an answer per se for your Smart Tire issue, but I wanted to add a comment regarding something that may seem "obvious" to some, but I still felt needed saying.

DO NOT for any reason crawl under that coach while it's on the jacks....
While I was in Gillette two years ago at the International Rally I experienced a blown hydraulic line in my otherwise brand new LADB and in essence rode the coach right down to the axles. I might add this happened all on it's own without any warning...

The HWH techs who were in attendance would not crawl under the coach and it wasn't "fixed" until I went to HWH in Iowa....

My point simply is..... BE SAFE!!!

Cruzer · 10-15-2008, 10:52 AM

I guess anything is possible but I don't think the ods are in favor of a damaged air line or else you'd have other issues to deal with. I've thrown my coaches through some pretty tough stuff before and never has my SmarTire give a high temp alert.

The system can manually be read and it is configurable for limits. My initial guess is that the high temp alarm setting is set too low and prematurely warning you. The inner duals will bear much of the weight on a crowned road so it stands to reason they'd be the first to trip the alarm. Mine is still set at the factory default of 176 degrees and I've never seen them go over 135 degrees. Although I have to admit that when I'm climbing up Mount Evans or the Beartooths and the coach is yawing back and forth it's not really the time I take to manually check my tire temps.

But, the alarms never went off so they can't be going over 175. I wonder if Newmar set your alarm limits too low?

RVDude · 10-15-2008, 10:55 AM

I'll echo rebels caution - HWH is not for crawling under a caoch w/o additional safety jacks of sufficient capacity (hint: the jack stands at walmart can't hold the weight).

A few thoughts

Air brakes use air pressure to release the brakes and springs to apply them. So, a broken air line (you should hear it whistle) could cause a brake rub and heat. So it's possible but you should hear the air leak when running.

Your Smartire still might not be set correctly. Go thru the programming (in your manual) and check the settings. Pressure might be set too low, or most likely the slope factor is improperly set - might be set for the slope of a low pressure (toad) tire and not the slope for the high pressure coach tires. This slope setting is easily overlooked and governs the the rate at which Smartire "adjusts" the various alarms for temp. My guess is it is your slope setting.

Third, what is the actual temp indicated that it is alarming at? If you have the Smartire display you can read psi, temp, and delta-psi. It might not really be all that hot hence pointing back to slope.

Lastly, it could be a erroneous readings due to sensor failures or maybe even bad signals because the debris damaged 1 or more antennas. There should be an antenna mounted between the front wheels, one mounted centrally between the tag and drive, and if properly installed a third at the rear bumper for the toad. These antennas look like a UHF antenna, about 8 inch long slim whip, with a very small nipple on the end. They will probably be pointing straight down and are on a magnetic base. You can look at the Smartire control unit to see if there are 2 or 3 antennas installed. A 3 antenna system will have a T connector joining 2 of the coax antenna BNC connectors to one of the 2 antenna ports.

Lug_Nut · 10-15-2008, 02:46 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Air brakes use air pressure to release the brakes and springs to apply them. So, a broken air line (you should hear it whistle) could cause a brake rub and heat. So it's possible but you should hear the air leak when running. </div></BLOCKQUOTE>

The Dude is correct, but please understand he is talking about only the park brake, not the service brakes. There are so many people out there that think that air is released that causes brakes to activate on springs. This is not true. Air pressure supplies pressure to a rod that via a cam applies braking action. This applies to all the axles. The drive axle has a double chamber with the rear part being a large spring. When you release the park brake the spring is overcome causing the brakes to be released. The brakes are then working in the serice position, air pressure creates braking pressure.

If anyone does not know how this works, I would recommend that you seek training in this subject. I've read many posts on other forums that don't have a clue on this. It could one day save your life.

Peter

RVDude · 10-15-2008, 03:16 PM

Good point lug, it would be difficult to hear an air leak if you were running down the road listening to the service side!!!

Chickadee · 10-16-2008, 03:59 AM

Thanks guys!! Great input...AND...I thank you for the caution about NOT crawling under the rig when on jacks or aired up....I did know that but appreciate your warning anyway. We'll reprogram our Smart Tire and check settings. We're still not clear on that "SLOPE" setting...and frankly, neither was the tech at Newmar when setting it up...so as mentioned, it could likely be our settings. Also, Lug_Nut, I'm glad you instructed folks about the difference between "parked brakes" vs. "service brakes" relative to operation. Having driven grain trucks from Dakota to the harbor at Duluth,MN as a young guy, and having worked on air brake systems, I never could understand it when folks on this, and other forums, seemed to think springs applied the "service braking" and air realeased "service braking". ANYWAY...thanks for all of your input. Steve

movin-on · 10-16-2008, 04:53 AM

And as we all should know... The 3rd part of the system is the emergency brake... When there is insufficient air in the system to keep the spring in the chamber restrained, the emergency brakes automatically engage. Spring brakes will apply generally when air pressure drops to a range of 20-45 psi. When air pressure falls below 60 psi, a low pressure warning light will activate and/or an audible buzzer will sound.
You should test this system often...It may save your life also...

rebelsbeach · 10-16-2008, 05:44 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by movin-on:
And as we all should know... </div></BLOCKQUOTE>

A little

for Smart Tire, but.....

Those folks who operate a coach with air brakes should indeed take the time to seek out proper training on the operation of vehicles with these systems.
It is important not only to know how to operate these vehicles, but to understand how these systems operate as well.

I wonder how many folks know what those little lanyards are for which are coiled up next to those air tanks?

movin-on · 10-16-2008, 06:33 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by rebelsbeach:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by movin-on:
And as we all should know... </div></BLOCKQUOTE>

A little

for Smart Tire, but.....

Those folks who operate a coach with air brakes should indeed take the time to seek out proper training on the operation of vehicles with these systems.
It is important not only to know how to operate these vehicles, but to understand how these systems operate as well.

I wonder how many folks know what those little lanyards are for which are coiled up next to those air tanks?

</div></BLOCKQUOTE>

Not off topic if the op thought he severed an air line and what probably would have happened if he did..

Cruzer · 10-16-2008, 11:29 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by rebelsbeach:
.....

I wonder how many folks know what those little lanyards are for which are coiled up next to those air tanks?

</div></BLOCKQUOTE>

That's one of the reasons that Tiffin got rid of the lanyards on their Powerglide chassis. THey went to a handy petcock system in a basement storage bay. The valve is in the compartment but the air dumps on the ground on the backside. I was surprised when I saw them and thought that was a very cool idea. Sure beats reaching into the wheel well area.

Chickadee · 10-17-2008, 04:14 AM

Say, "movin-on": ya,....I agree that the discussion about air brakes does relate to possible causes to the Smart Tire alarm question. Sooooooo.....NOW I'm worrying that the encounter with that gator MAY have caused some kind of small leak in the air system which holds the park brake spring retracted such that it ..s l o w l y.. is released thereby applying drag to the parking brake while underway????.....is this stupid or is it even possible???? P.S. I DID find out what those lanyards were in my R. front wheel well....to drain any accumulated moisture from air system cylindars. ANYWAY...sure appreciate your guys help and discussion. I learn alot from all of you. Thanks. Steve

Chickadee · 10-17-2008, 04:21 AM

Ooooops, Sorry, forgot something:....Does anyone understand the "SLOPE" setting on the Smart Tire screen? What I get (and THAT doesn't account for much

) is that the "slope" someway controls or monitors the gradual increase or decrease of pressure/temp. as the tires heat up and cool down while traveling???????? Geeeze,....if I understood it, maybe I could set it correctly. Thanks. Steve