Brake Lock-up on Dual Axle -Tire distruction

ZekenSpider · 12-08-2009, 04:12 PM

This thread may apply to the 3326 only as it is the only TM with dual axle configuration.

My 2010 3326 (delivered in August of 2009) has been a joy to tow and camp in. The shake down trip of 220 miles was a pleasure as was a 1,700 mile trip to and from Petaluma, CA and a weekend trip to the Catalina Mountains in Tuscon.

The brakes have always worked correctly, but would occasionally feel a little "grabby" at slow speeds. Tire /wheel temperatures (TST tire monitor) always appeared normal (usually in the 95 degree area except in the late summer in Phoenix). The brake adjustment was checked OK at 210 miles and was due again in about 500 miles.

Last week, while heading to my local dealer (AZ Campers and Trailers) to have the heater exhaust system replaced, I noticed white smoke behind the TM. Upon examination, I found the TM front, right wheel locked up (not turning). By the time I drove to a safe place to jack up that side, the tire had worn through the belt and was going flat. Only then did my TST monitor tell me a problem existed.

AZ Campers and Trailers sent a field tech to my assistance. After checking for a possible electrical malfunction, he pulled the tire, then with great difficulty, the hub/drum. The drum was found to be 1/8th inch out of round and had probably locked-up the brake at my last traffic signal stop.

The work is not yet done (waiting for parts), but Dexter Axle is replacing the entire hub/drum/brake system on the front axle, right side and TM is supplying a new tire. All the work is being done under warranty. The real question is what happened?

The only answer so far is "stuff happens". I see, on other RV forums, that dual axle brake lock-up is an occasional discussion topic and warped drums are considered the cause. What is really clear is; on a dual axle trailer, a tire can be destroyed within just a few blocks of driving if a brake-locks up. And... it is very hard to detect that it is happening. By the time you see the smoke, it is too late.

It looks like I need a wheel rotation sensor as well as all the other bells and whistles. On the other hand, this probably will not happen again. Heh, heh heh.

Jerry

**ShrimpBurrito** · 12-08-2009, 06:59 PM

Sigh. Sometimes a tent looks so attractive.

Maybe I don't have a good perspective on this, but to me, a drum being out of round by 1/8" sounds very, very bad. Bad as in it should have been very obvious at Dexter's manufacturing line. If it wasn't a manufacturing defect, perhaps someone over torqued your lug nuts....I am guessing that could potentially be adequate force to warp a drum.

You say you saw dual axle brake lock-up discussed a few times on other forums....did you see anything on single axle lockup? If it locked up due to a warped drum, that would make it just as likely to happen on a single axle.

Dave

ZekenSpider · 12-08-2009, 08:55 PM

Quote:

Originally Posted by ShrimpBurrito

Sigh. Sometimes a tent looks so attractive.

Maybe I don't have a good perspective on this, but to me, a drum being out of round by 1/8" sounds very, very bad. Bad as in it should have been very obvious at Dexter's manufacturing line. If it wasn't a manufacturing defect, perhaps someone over torqued your lug nuts....I am guessing that could potentially be adequate force to warp a drum.

You say you saw dual axle brake lock-up discussed a few times on other forums....did you see anything on single axle lockup? If it locked up due to a warped drum, that would make it just as likely to happen on a single axle.

Dave

So far my search for what may cause lock-up has not turned up any single axle examples. I'm sure it can happen, but is probably noticed (felt) more easily by the TV driver.

The 1/8th out of round warped condition was considered really bad by the dealer technician (actually the first tech to work on the brake could not figure out what caused the lock-up). Fortunately there was an old retired horse trailer mechanic on duty that day and he said he thought the drum was warped. It was. He said "it happens". He had seen a few in his experience but never could figure out what caused it.

The Dexter Axle manual and website have no statement on the subject and only comment that over-torquing can damage the studs. The warped hub shows up as a reason for brake lock-up in Dexter's troubleshooting charts, but they offer no explanation for what causes the warping. I suspect it's possible to bend a drum by tightening studs out-of-sequence or by having weight on the wheel when it is tightened.

The axles are shipped and handled in a way that a drum could be bent by a blow such as dropping. Who knows!

I have asked the dealer to examine the other three drums.

We will see.

Jerry

Wavery · 12-08-2009, 09:09 PM

I'm a little surprised that they didn't catch that when they adjusted the brakes @ 210 miles...........or......did they really do it???

ZekenSpider · 12-09-2009, 12:38 PM

Quote:

Originally Posted by harveyrv

I'm a little surprised that they didn't catch that when they adjusted the brakes @ 210 miles...........or......did they really do it???

They said they did...heh, heh. I checked them myself about a week later and everything felt OK. I could hear a slight drag as I rotated each wheel. The paint on each drum still looked fresh (black) and nothing appeared out of round. Of course I may not have noticed a 1/16th inch change in radius. The paint was still black on the drum when it was removed by the dealer.

I am still puzzled why this would cause a lock up that would not release after backing up. Still looking for answers.

Jerry

12-09-2009, 01:11 PM

If you adjust a brake so that it just touches the drum and then you do some breaking the spot that just touches causes more heat because the drum has expanded. Now there is more pressure from shoe to drum causing more heat and even more pressure when the brakes ARE NOT applied. Snow ball effect and then the brake locks up. Your brakes probably were adjusted and the out of round was possibly caused by overheating. I've seen the exact same thing on elevator brakes when the are NOT adjusted to lift completely during runs. That little bit of drag builds over many runs and then sets off the building smoke detector. But then again it was 1200 miles since the brake adjust. Maybe a slight out of round condition caused the heat snow ball effect which then caused a big out of round condition.

It could of happened this way and maybe not. Robert

MudDog · 12-09-2009, 06:55 PM

There's a long discussion about a similar incident on this blog:

http://http://rv-dreams.typepad.com/.../09/index.html

In the end, I'm not sure they ever got to the root cause (bad drum, bad magnets, brakes adjusted too tight on that wheel) but they had re-occurences of the original problem after replacing the drum. Dexter ended up covering the costs and I believe paying for a tire replacement.

**mjlaupp** · 12-10-2009, 02:55 PM

Quote:

Originally Posted by MudDog

There's a long discussion about a similar incident on this blog:

http://http://rv-dreams.typepad.com/.../09/index.html

In the end, I'm not sure they ever got to the root cause (bad drum, bad magnets, brakes adjusted too tight on that wheel) but they had re-occurences of the original problem after replacing the drum. Dexter ended up covering the costs and I believe paying for a tire replacement.

Error, try this one:

http://www.rv-dreams.typepad.com/rvd.../09/index.html

Mike

MudDog · 12-10-2009, 10:38 PM

Quote:

Originally Posted by mjlaupp

Error, try this one:

http://www.rv-dreams.typepad.com/rvd.../09/index.html

Mike

Woops - thanks Mike!

--jim

12-11-2009, 09:23 AM

Assuming the original drum was in spec, then warped brake drum/rotors are almost always caused by the brakes overheating, then cooling rapidly. On a car, this would be caused by either driving habits, terrain, or another undiagnosed brake issue causing one brake or axle to work harder then the other.
If this brake started off not being adjusted probably, it would heat up even when the brakes are not applied. The normal temps this time of the year would cool the drum rapidly when stopped for a burger, etc. You then take off and start the process all over again....snowballing the issue.
The fact that this brake totally locked up puts it in a category by itself...making me think the drum was defective to start with, put on incorrectly, or dropped at some point.

After getting several new brake rotors that were warped right out of the box, I raised hell with the local parts store manager. I was told this was common due to shipping and stocking. I told him they need to quit hiring gorillas. Also considering that it's almost impossible to buy anything not made in China, Malaysia, etc.
Based on this, the potential for a new warped drum going on from the factory is not that far fetched, and unless TM is checking each one prior to installing, then "there ya go..".

A good "pre-trip check" that anyone can do for this would be to simply jack each side of the trailer and spin the wheels with your hands. If the tires spin freely, you're in good shape. If any of them tend to lope or have a "catch point", then you have a warping problem starting. If not corrected, it will simply get worse as time goes by.