Brakes Locking Up

Axles and Suspension Systems, Brakes, Brake Controllers, Wheels, Tires
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KYAvion
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Brakes Locking Up

Post by KYAvion »

I have a Prodigy P3 brake controller and about three months ago when towing my former 79 Airstream my brakes locked up while driving slowly (less than 10 mph) and pressing the brake pedal. They would free up when the brake pedal was released, but would lock again with the slightest pressure against the pedal. I had just put brand new Dexter axles on that trailer so everything was good. After pressing the voltage button and probably the boost button the issue corrected itself.

Just this weekend when towing my new Avion I had the same experience. I was going around 5mph and my brakes locked with just the slightest pressure against the pedal. I played with the buttons on the 3P with no success. I hopped out and unplugged and replugged the umbical and things reset, or coincidentally started working again.

Anyone know why this is happening and what the fix is?
KYAvion
1984 Avion 30R
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KYAvion
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Re: Brakes Locking Up

Post by KYAvion »

So I spoke with Tekonsha today and they are having me mail in my brake controller so they can test it. Apparently this issue can be caused by a bad computer board.
KYAvion
1984 Avion 30R
Mark R. Obtinario
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Re: Brakes Locking Up

Post by Mark R. Obtinario »

I have had problems with my Draw Tite unit.

I was told by someone who knows what he is talking about that when a trailer has been sitting for any amount of time you are going to have to adjust the gain in order to not lock up the brakes. When trailers sit the moisture in the air can cause rust to from on all of the surfaces. When the lining hits the rust it will grab. Once you have made a few brake applications the rust will be worn off and you will need to readjust the gain again.

If the trailer has been sitting long enough the surface on which the magnets ride can get covered in rust as well. When that happens the magnets have a hard time making contact and won't pull hard enough to apply the brakes. In order to clean the surface you will have to pull the drums off and use a cleaner and a wire brush. It is also a good time to repack the bearings. Once you clean the surface up they will work just fine.

Our 34V hadn't been licensed for nine years when we purchased it. I got it home without doing anything but the distance was less than 20 miles and I traveled the whole distance below 40 MPH. Three of the six sets of bearings were completely dry and every brake drum was rusty. Once I got everything greased back up and the surfaces cleaned up I went to take it for a test drive.

I couldn't understand why it was pulling so hard. It hadn't pulled that hard bringing it home. Come to find out someone had changed out the trailer plug from a 7-flat to a 6-round plug. I had used a convertor plug to get it home. I finally realized someone had wired the plug incorrectly and the 12-vdc hot line was hooked to the brake signal line. In other words I was getting 100% brakes all the time.

You know, when all six wheels on an Avion 34V are locked tight it is really hard to pull. :)

Now every time I use it after it has sat for a while I always turn down the gain until I have used the brakes a few times to get them cleaned up. Then I don't have the brakes locking up on me.
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KYAvion
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Re: Brakes Locking Up

Post by KYAvion »

Thanks, Mark. I'll have to keep what you said in mind for future outings. I can't imagine having three axles lock up hard like that. In the two scenarios with mine, the first occurred after driving about 2.5 hours, and it was on a brand new set of axles I had just put on our Airstream that we had at the time. The second time was with our new Avion, and it happened after driving about 2.5hrs as well. With each instance there was plenty of braking during the first couple hours, so I think any rust was probably removed by the time the lock ups happened. Each time it just seemed to occur out of nowhere.
KYAvion
1984 Avion 30R
Mark R. Obtinario
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Re: Brakes Locking Up

Post by Mark R. Obtinario »

Since both occurrences happened after a long speed run I would be inclined to think they grabbed because the magnets were getting a really good purchase on the drums.

I know that after a long speed run when I get into town onto surface streets I have to turn the gain way down to like 1 or 2. If I don't, when the brakes get applied, they really jerk the trailer when braking at slow speeds.

I like the gain to be turned way up while going highway speed. In an emergency braking scenario I want all six of those wheels braking as hard as they can as soon as they can so the trailer won't try to pass me while panic braking.
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KYAvion
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Re: Brakes Locking Up

Post by KYAvion »

I know exactly what you're saying and agree with your approach. Unfortunately, in both of these cases I had dropped the gain both before the lock up and after, and the brakes still locked hard.
KYAvion
1984 Avion 30R
Mark R. Obtinario
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Re: Brakes Locking Up

Post by Mark R. Obtinario »

Any new info on this issue?
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KYAvion
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Re: Brakes Locking Up

Post by KYAvion »

I received a new brake controller from Tekonsha, but haven't had a chance to use it yet. Hopefully it was just a fluke with my old one.
KYAvion
1984 Avion 30R
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