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DaKarch · 09-18-2015, 09:38 PM

A few more details from today's adventures in trailer brakes...

Put the hot wheel in the air tonight at the 145F and again wheel turned freely, no drag.

And the bearings both old and new slide off and on as they should.... not binding

As for play in bearing statement...No "excessive" play in bearings would have been a more definitive statement.

cwbiii · 09-18-2015, 09:42 PM

I would try switching that tire to another hub and see if the problem travels with the tire... if so then it on its way to a catastrophic failure... replace that tire and it should go away. Even a new tire can be bad if it has a manufacturing defect. Do you have a IR laser thermometer??? the kind you point at the tire and take a reading? If so try to localize the source of the heat by pulling over after a few miles and check rim and various parts of the tire (sidewall, edge, contact patch) and this may give you a better clue. We use one of these while auto-crossing to keep the vehicle tires in the optimal temp range for traction.
They are very accurate.

Chuck

Andrew T · 09-19-2015, 04:51 AM

If you have not already I would definitely try switching tire locations.

It could be alignment but you would be getting tire wear if it is. The Passenger front tire is the most common to be knocked out of alignment.

Eliminating all of the above, my guess is you have a bent spindle which is putting extra pressure on a bearing not enough to overheat it but enough the get the hub warm.

It will likely run for ever it you keep good grease in it, or you could change the axle.

If you do change the axle, put the new axle on the rear and move the rear one to the front. Your current axle rides better than the new ones do.

Andrew T

JCWDCW · 09-19-2015, 06:24 AM

Is the drum on that wheel different...or out of round? Is it possible that wheel is getting more voltage due to bad connections in the harness feeding the other wheels? I would have expected the pair of wheels on one side would be affected not just one if it is a high resistance problem. You could try checking resistance from the 7 way back to each magnet...might give some insight. Ground the connection at the plug to the trailer frame and check resistance between magnet supply and the backing plate at each wheel to get around the distance from plug to wheel with your meter.

Note that if one wheel has the brakes backed off more than the others, that brake will be grabby and do more work since the leverage on loosely adjusted brakes is greater than shoes that are set up tight. The linkage gets to move further which increases the leverage on the mechanism.

JCW

SteveSueMac · 09-19-2015, 06:32 AM

Apologies in advance if this is as stupid as I think it might be - but is there any way that particular wheel is carrying significantly more load than the others?

Wingeezer · 09-19-2015, 06:57 AM

Quote:

Originally Posted by SteveSueMac

Apologies in advance if this is as stupid as I think it might be - but is there any way that particular wheel is carrying significantly more load than the others?

I was starting to wonder the same thing. Even if it is not related to the way the trailer is loaded, could the rubber suspension somehow have "frozen" on that end of the axle. maybe causing the bearing to see usually high loads?

Brian.

DaKarch · 09-19-2015, 06:51 PM

SOLVED SOLVED SOLVED SOLVED SOLVED (I hope....)

New backing plate was causing the brake drag.

So I had grand plans of swapping backing plates more debug, more wrenching today. But I decided to go to local equipment trailer store (Tom's Equipment, can't say enough good things about this place) before they closed at noon to buy a new made in USA Dexter branded backing plate before they closed.

Noticeable difference is that front pad; although the correct length of material it is placed higher on the shoe. I think as the brakes lost material (which they lost a lot of) the shoes started to bind even more. So I put it on...and drove 70 Miles with no brake heat up. Keep in mind that 20 miles and I was smoking hot consistently.

Now hind sight is usually 20/20. The path that led me off was that it was a new backing plate sold by a reputable store (camping world). And I drove NC to Fla Keys and back to PA with no excessive heat. So it had to be something else! Should have followed KISS motto (Keep it Simple Stupid).

Then you are so far in... that when I put a thermal couple on the drum and the outer was slightly warmer than the inner I found a way to convince myself that it had to be a bearing or warped drum....

The good of all of this is I have so much data that it will be interesting if the manufacturer will give me grief about a refund for this complex boat anchor.

Anyhow, I certainly hope this helps people out there.....because without the TPMS system and some understanding of how to interpret its data with the mechanical and electrical system ......I would have drove down the road until something broke and not known why. The Dill TPMS is now a net positive in my book and it has saved me the purchase price in repairs.

DaKarch · 04-29-2016, 06:54 PM

Thread going live again

Not solved... Same wheel heating up again after out of storage and first 2 trips.

Seriously considering new trailer side brake wiring.

switz · 04-29-2016, 11:40 PM

I wonder if the wheel alignment to the axle was checked? If the tire is not tracking true, there would be unusual tire wear and heat generation.

But a dragging brake seems like a high probability issue.

JCWDCW · 04-30-2016, 05:56 AM

Have you checked the linkage on the brake shoes. Take the drum off and move the magnet to expand the shoes.. If the shoes do not immediately return, or the linkage does not go back to home position you probably need to free up the main pivot point where the magnet arm turns to push the shoes out....speaking from experience. I just clipped the wires on my trip since I was only 50 miles from home. The issue disappeared and I was able to track the problem to the frozen linkage.

If it is dragging shoes the drum will heat first around the outer edge. If it is bearings the hub will get hot first. Reassemble the wheel leaving the hubcap off and start driving ...check every 5 minutes or less to see which part of the drum is getting hot first . That will lead you to the source.
JCW

paiceman · 04-30-2016, 06:16 AM

I don't know where you are in Pittsburgh, but if it were me as I don't know much about brakes, I'd either call or take the trailer to Carl and Alex at what was Airstream of Western PA and let them have a look see. Combined over 60 years of Airstreams I am just guessing here but they might have seen this before.

Good Luck

Bud

DaKarch · 04-30-2016, 07:12 PM

Took half the belly pan off today. Connections at wire nuts looked fine. But the way its wired could explain why an individual wheel would have a problem. Going to run new wires.

DaKarch · 04-30-2016, 07:18 PM

Some pics attached

**Action** · 05-04-2016, 04:56 PM

Wow, so looking forward to the posting of the solution.

>>>>>>>>>>>>Action

DaKarch · 05-06-2016, 09:37 PM

Attached a few more photos. Have made slow progress this week, however, the pictures are of the wire off the wheel that was heating up. Hard to get a good picture but it shows corrosion about 20 inches back from the magnet connection.

I found 10 inches of oxidized wire and then stopped looking. It was only on the hot wire.

Corrosion effects resistance. So the question is does the corrosion effect the magnet and increase the brake force?

Should have it all done and buttoned up tomorrow. The 7 pole pig tale, break away, and all wires from bow to stern will be new. Will post an update after the road test.

Caffeinated · 05-06-2016, 09:49 PM

I just want to say I hope this is the answer. This would drive me mad.

Mike

Wingeezer · 05-07-2016, 06:54 AM

Quote:

Originally Posted by DaKarch

Attached a few more photos. Have made slow progress this week, however, the pictures are of the wire off the wheel that was heating up. Hard to get a good picture but it shows corrosion about 20 inches back from the magnet connection.

I found 10 inches of oxidized wire and then stopped looking. It was only on the hot wire.

Corrosion effects resistance. So the question is does the corrosion effect the magnet and increase the brake force?

Should have it all done and buttoned up tomorrow. The 7 pole pig tale, break away, and all wires from bow to stern will be new. Will post an update after the road test.

I have found the same thing on our trailer - it seems no matter how far you strip the plastic back on the wire, it is still black from corrosion. All wheels were this way on our trailer.

I like to solder my connections and then use waterproof shrink tube on them (the kind with the hot melt glue inside). In order to be able to solder corroded wires I have to splay out the individual strands and try to scrape the corrosion off with a knife as best I can, then re-twists them.

My impression is that as long as you can make good connections, the surface corrosion on the rest of the wire doesn't have a huge effect.

Could be wrong - but the reason I feel this way is that I recently changes all four complete brake assemblies on our trailer - making connections as described, and when I measured the current draw at full braking, it was right up to spec - close to 15 amps. I think if corrosion were a problem, this would not be so.

Be interested to see what you find though.

Brian.

**Action** · 05-07-2016, 10:46 AM

I would think corrosion would impact the current (not the voltage) such that brake application would be reduced or the magnetic current would be less in attraction to the rotating magnet surface of the brake drum. Reducing the force to the shoes. (Diminished braking versus other brakes with no corrosion) Just an opinion.

>>>>>>>>>>>>>>Action

DaKarch · 05-07-2016, 09:28 PM

Almost done....this job has been plagued by one dumb thing after another...

So if you think of I = V/R .... If R increases I should decrease and thus less magnetic force ~~~~ Less braking force

But if you think about it from the power equation or Joule’s Law: P = I^2*R ... as R increases more power goes into that circuit. So we know we should get say 12 V in the line which I was and new magnets should read about 3.5 Amps when cold which I was getting...

So P = (3.5)2^2 * 3.2 = 39.2 Watts of power at the magnet

Keep in mind that 3.2 ohms was read across the magnet....not the wire and magnet but it would be a series circuit which means it would be additive.

So if wire adds resistance say .5 ohms then,

P = (3.5)^2 * 3.7 = 45.3 Watts at the magnet

So current and volts can stay stable and the power can increase with resistance....and energy has to stay in equilibrium...

If I ever get it back together we will see if the road test supports my abuse of the laws of electricity...

Wingeezer · 05-08-2016, 06:58 AM

Quote:

Originally Posted by Action

I would think corrosion would impact the current (not the voltage) such that brake application would be reduced or the magnetic current would be less in attraction to the rotating magnet surface of the brake drum. Reducing the force to the shoes. (Diminished braking versus other brakes with no corrosion) Just an opinion.

>>>>>>>>>>>>>>Action

In my case when I recently changed all of my brake assemblies, I found the same blackening of the wires on all wheels - and if memory serves me, both wires leading to each magnet exhibited the same thing.

Brian.