Brakes, dilemma.

[freewayrandy]

I just had to have all new brakes put on my trailer at about 13K miles. 3 of the 4 were metal to metal. Usually run the controller 5/6. Has anyone heard of a brake test using a compass? It says with the brakeaway pin in (no voltage to electromagnets) put a compass up to the hubs. Compass should point north. Pull the pin and compass should point to the brakes. Well, With the pin in, I have 3 that the compass is pointing to the brakes! For the heck of it, I ordered a new breakaway switch. What else could possibly be an issue?

[freewayrandy]

Thanks to all for your input and support.

[Sjm9911]

freewayrandy wrote:
Just to clarify things, I had all new brakes, from the backing plates out, installed at a local RV repair place. I've ordered a new DC current tester to check everything out. Just don't want the same thing happening to the new brakes.

I hope it is all worked out now, just keep an eye on it. Get a volt meter and test the voltage at the conection points. Thats the best way.

[Sjm9911]

JRscooby wrote:

Sjm9911 wrote:
Lol, then just say its not a good test. Done. Personally, its the first time I ever heard of using a compass, pull the wheel and test the magnet with a metal tool, yes. Meter yes. I have had my share of weird brak problems. So sometimes the fix is evident, sometimes its not. I did learn, that with the harder stuff , its easier to rewire then to troubleshoot.

The most likely problem with e-brakes will be magnet not getting power. And used right, a compass will tell you this magnet is not working with no teardown, or even getting under the trailer. This is why LEOs will use it roadside on CMVs (in theory, a fish hook on a short line could work)
My problem with the "easier to re-wire" crowd is it is also easier to just leave the old wires there. And because they could not find a problem, likely the rewire job will have problems shortly. So they rewire again. Then when somebody does try to troubleshoot, bunch of extra wires to sort out.
Off topic but kinda funny. I decided to take Bobcat out to work with my '54 F5. No CB, so I was surprised by a roadside safety inspection. I watched the mirror, pumped the pedal while the kid in uniform waved his compass around the trailer wheels. He gets my Out Of Service paper all marked up, hands it to me to sign. "What makes you think my trailer brakes don't work?" loud for the senior inspector to hear. Senior, who had been inspecting my stuff for years, looked at the tongue of trailer, "Surge brakes are PITA. Scooby, do they work?" I asked if he wanted me to pull break-away. "Naw, we'll just mark this 1 as training."

Well you have to do what you have to do sometimes. I left my old wires there, caped and wound. They were run inside of the camper. No way was I removing them. And no way I could find the problem. It was a broken wire somewhere that caused an intermittent loss of power when I was driving only. I rewired the hubs and kept testing and found nothing. Pulled the camper away and it would read no power to the brakes, off and on. Should have just rewired it from the start, that took a few hours. I spent days troubleshooting. Grounds, wires, TV, and nada.

[time2roll]

freewayrandy wrote:
Just to clarify things, I had all new brakes, from the backing plates out, installed at a local RV repair place. I've ordered a new DC current tester to check everything out. Just don't want the same thing happening to the new brakes.

Excellent. Please post what is found.

[JRscooby]

Sjm9911 wrote:
Lol, then just say its not a good test. Done. Personally, its the first time I ever heard of using a compass, pull the wheel and test the magnet with a metal tool, yes. Meter yes. I have had my share of weird brak problems. So sometimes the fix is evident, sometimes its not. I did learn, that with the harder stuff , its easier to rewire then to troubleshoot.

The most likely problem with e-brakes will be magnet not getting power. And used right, a compass will tell you this magnet is not working with no teardown, or even getting under the trailer. This is why LEOs will use it roadside on CMVs (in theory, a fish hook on a short line could work)
My problem with the "easier to re-wire" crowd is it is also easier to just leave the old wires there. And because they could not find a problem, likely the rewire job will have problems shortly. So they rewire again. Then when somebody does try to troubleshoot, bunch of extra wires to sort out.
Off topic but kinda funny. I decided to take Bobcat out to work with my '54 F5. No CB, so I was surprised by a roadside safety inspection. I watched the mirror, pumped the pedal while the kid in uniform waved his compass around the trailer wheels. He gets my Out Of Service paper all marked up, hands it to me to sign. "What makes you think my trailer brakes don't work?" loud for the senior inspector to hear. Senior, who had been inspecting my stuff for years, looked at the tongue of trailer, "Surge brakes are PITA. Scooby, do they work?" I asked if he wanted me to pull break-away. "Naw, we'll just mark this 1 as training."

[freewayrandy]

Just to clarify things, I had all new brakes, from the backing plates out, installed at a local RV repair place. I've ordered a new DC current tester to check everything out. Just don't want the same thing happening to the new brakes.

[MFL]

BarneyS wrote:
Perhaps the wire going through the axle has worn through and shorting out that one wheel magnet. Pretty common problem and I'm surprised nobody has mentioned it here. Also perhaps I am not understanding the OP's problem.
Barney

Good point Barney, but in my experience, the axle to wire shorting, causes brakes to vary from little braking, to severe braking, pending contact of bare wire.

Jerry

[BarneyS]

Perhaps the wire going through the axle has worn through and shorting out that one wheel magnet. Pretty common problem and I'm surprised nobody has mentioned it here. Also perhaps I am not understanding the OP's problem.
Barney

[Sjm9911]

Lol, then just say its not a good test. Done. Personally, its the first time I ever heard of using a compass, pull the wheel and test the magnet with a metal tool, yes. Meter yes. I have had my share of weird brak problems. So sometimes the fix is evident, sometimes its not. I did learn, that with the harder stuff , its easier to rewire then to troubleshoot.

[JRscooby]

You got a compass? How 'bout a cast iron skillet? Put 1 in each hand, and bring them together. Does the needle move? Is the skillet getting electricity all the time?
Not to dog on the OP, but he heard something, or more likely saw it on the 'net, then acted without putting any thought into what should happen.

[Sjm9911]

Ok my terminology is wrong, but the op states there getting power to 3 of the 4 hubs without doing anything using the compass test. So, no pin pulled , no brakes applied and hes showing 3 hubs with power. Not 3 hubs with power while depressing the brake or pulling the pin on the breakaway switch. Im only going by what they posted. I totaly get and agree with what your saying, but the op is stating the opposit. It dosen't have to be full power there getting to ware the shoes, just a little to enguage them. As you said, the test just shows power, not how much. Thats where the meter comes in. If you ever saw a seized brake caliper on a car, it dosen't always smoke or cause any other problems then worn pads. Without the op coming back to clarity, I can only go by what they said.

[JRscooby]

If properly used, the compass can tell you that the magnet is working.
Hold a compass close to hub, below center but above bottom of drum. The magnetic needle will point to hub (No Zee, your fone will not work) Move compass away until needle points back north. Have helper apply brakes, the needle should swing back towards drum. Now this will not tell you everything, but will tell you the circuit is good enough for magnet to move the needle.
Now the OP has not reported smoke, bearing or tire failure, so it is safe bet when let off brakes, all are released.
You and 3 of your friends are carrying a pool table. 1 stops to take a phone call, can you and 2 handle the load? Maybe, but lot more strain. The OP has 1 brake on the phone.
Electricity likes to be where it's at. If it can't see a way to get back, it won't go anywhere. A open circuit means there is no way for it to go around. There is no open on the 3 that work
Decades of working on automotive electrical, most problems come from using the chassis for ground, so the first thing I would look at would be where the wire hooks to ground. It might be a short, but most likely somewhere between where that wheel circuit branches off and ground there is a open circuit.

[Sjm9911]

But if the compass test works, and I can only go by information I'm given, then they have power to 3 of the 4 brakes. How much is unknown. This would also cause premature ware on those 3 assemblies. It would also exclude a faulty break magnet on the good pad assembly. So that leaves an open wire feeding power to the other 3.

[msmith1_wa]

I agree with what JRscooby has been saying. With one brake not working the controller would need to be set to a higher level and then cause the brakes that do work to wear more quickly.

There were a couple others on this same track, but the rest of you are making this more complicated than it is.

The OP needs to figure out why that one magnet is not working. Whether it be a bad magnet or a wiring issue.