Simple instructions for testing brakes?

[lbdesign]

Hello all,
I've read a number of brake discussions before posting, and learned a lot, but still have a few questions. (I'm a computer guy, not a mechanical guy.)

My electric brakes stopped working. My Tekonsha Prodigy RF brake controller says all systems are good. So the very nice Tekonsha tech support person suggested I test the voltage at the brakes on each wheel. His theory is if the current is there, then the brakes are stuck/seized. I borrowed a multi-tester. I have no idea where to stick the probes. Can you point me to a diagram online of the brake parts, or other very basic instructions?

Background:
It's a 2004 22' with two axels.
The brakes worked fine 18 months ago, but when I towed it to the dealer for service last month, they didn't engage at all. I had the dealer service them, and the dealer says they are fine, yet when I drove off the lot, they still didn't engage. Before I bring it back to the dealer (driving again with no brakes), I want to be sure what the problem is, because now I don't trust the dealer, who should have done a test. I figure, if the customer says "the brakes don't work, please fix them", and leaves the trailer, tow vehicle and controller, then the dealer should have everything they need to check the entire system and do a road test :-)

thanks all for putting up with my probably very basic question, but maybe it will help others too.

[lbdesign]

PS: elsewhere in this forum I learned that you can also test electric brakes by holding a compass next to the wheel as the brakes are applied. Is this good advice? It seems easier than using the multi-tester.

[dwightdi]

Compass works for me. It is likely that the brake controller is miss adjusted or shot. Test for voltage at the output of the tow vehicle. It takes two people to do it properly. The dealership likely tested the trailer electrically and found the brakes to be in good order with their tester.

[HowieE]

If the dealer says the brakes work on the trailer the first thing to check is the TV. Take the voltmeter, set for 20 volt range DC and put in in the 2 bottom terminals of your truck electrical connector at the rear bumper. While watching the meter have someone manually engage the brakes with the manual lever. You should see upwards of 10 volts or more depending on how aggressive you have the controller set. If you do not see voltage there ethe problem is in the Truck wiring. If you see negative voltage you just have the probes reversed and not a problem.

If you have voltage there connect the cord to the truck. Jack up one side of the trailer and while spinning a wheel have someone manually hit the brakes. The wheel should SLAM to a stop. If not the wiring in the trailer is open. Test each wheel this way. If all fail the wire from the point where all 4 wires come together to the front of the trailer is open. The dealer may have tested the brakes by applying voltage directly at the wheel and thus not found the problem

[Inland RV Center, In]

Originally Posted by lbdesign

Hello all,
I've read a number of brake discussions before posting, and learned a lot, but still have a few questions. (I'm a computer guy, not a mechanical guy.)

My electric brakes stopped working. My Tekonsha Prodigy RF brake controller says all systems are good. So the very nice Tekonsha tech support person suggested I test the voltage at the brakes on each wheel. His theory is if the current is there, then the brakes are stuck/seized. I borrowed a multi-tester. I have no idea where to stick the probes. Can you point me to a diagram online of the brake parts, or other very basic instructions?

Background:
It's a 2004 22' with two axels.
The brakes worked fine 18 months ago, but when I towed it to the dealer for service last month, they didn't engage at all. I had the dealer service them, and the dealer says they are fine, yet when I drove off the lot, they still didn't engage. Before I bring it back to the dealer (driving again with no brakes), I want to be sure what the problem is, because now I don't trust the dealer, who should have done a test. I figure, if the customer says "the brakes don't work, please fix them", and leaves the trailer, tow vehicle and controller, then the dealer should have everything they need to check the entire system and do a road test :-)

thanks all for putting up with my probably very basic question, but maybe it will help others too.

The first thing you always must do with any electrical problem, "is isolate".

Have the rig hooked up, ready to hit the road.

Leave the engine running.

Go back to the A-frame and pull the cable from the tow vehicle.

Then, pull the breakaway switch cable.

Get back in the tow vehicle and see if you can move the rig.

If you cannot move it more than a few feet, then trailer brakes are OK and the issue is with the tow vehicle, or connecting cable.

If you can move the rig, more than a few feet, then the problem is within the trailer.

That then tells you which way to focus your attention.

CAUTION: DO NOT LEAVE THE BREAKAWAY SWITCH CABLE PULLED MORE THAN A MAXIMUM OF 5 MINUTES.

If you do, and the brakes are working, you will burn up the magnets, and if long enough, detemper the axle spindles.

Andy

[richinny]

when was the last time you checked the break-away switch? if the brakes activate when test the switch you may not need to go under the trailer :-)

don't leave them activated for more than a few minutes or you'll fry the magnets.

[lbdesign]

This is all great advice, thank you everyone! While I was away from my computer, a neighbor was helping me test the brakes with a hiking compass. We read a strong magnetic disruption at each of the four tires when the controller was engaged. Yet when I was towing, engaging the controller resulted in no brake action at all.
So should I assume the drums are stuck in some way? It's been parked near the ocean for 18 months. I can report that the disc brakes in my car develop a rusty film on them that makes a rubbing sound, that only several miles of driving and braking can wear away. (that's the car, nothing to do with the Airstream).

[Inland RV Center, In]

Originally Posted by lbdesign

This is all great advice, thank you everyone! While I was away from my computer, a neighbor was helping me test the brakes with a hiking compass. We read a strong magnetic disruption at each of the four tires when the controller was engaged. Yet when I was towing, engaging the controller resulted in no brake action at all.
So should I assume the drums are stuck in some way? It's been parked near the ocean for 18 months. I can report that the disc brakes in my car develop a rusty film on them that makes a rubbing sound, that only several miles of driving and braking can wear away. (that's the car, nothing to do with the Airstream).

The only way for you now, is to remove a drum and see what the brake looks like.

Being near salt water that long could cause all sorts of trouble, not only for the brakes, but a great amount of rust on the chassis, as well.

Andy

[lbdesign]

Originally Posted by Inland RV Center, In

The only way for you now, is to remove a drum and see what the brake looks like.

Being near salt water that long could cause all sorts of trouble, not only for the brakes, but a great amount of rust on the chassis, as well.

Andy

Thanks Andy. If I don't need to tow it for pleasure for another 6 to 12 months, should I wait to have the brakes serviced again until much closer to my future travel date? Because it will only seize up again?
(I try to keep it clean, to help with the salt.)

[ROBERT CROSS]

lbdesign,

Did the dealer road test your trailer?

It could be your RF controller isn't transmitting when underway?

Bob

[lbdesign]

Bob, they did not hook up the TV or test the controller, even though they had both on hand (and a window of 30 days to do the work).
When I am underway, the controller reports all connections are good. With the Prodigy RF, if the connection is lost, it displays an error code.

[KYAirstream]

Originally Posted by Inland RV Center, In

CAUTION: DO NOT LEAVE THE BREAKAWAY SWITCH CABLE PULLED MORE THAN A MAXIMUM OF 5 MINUTES.

If you do, and the brakes are working, you will burn up the magnets, and if long enough, detemper the axle spindles.

Andy

This sounds serious. Would it be a good idea to have a switch somewhere for the breakaway cable so that a kid or other person messing around couldn't leave the cable engaged?

[Wazbro]

Originally Posted by KYAirstream

This sounds serious. Would it be a good idea to have a switch somewhere for the breakaway cable so that a kid or other person messing around couldn't leave the cable engaged?

A switch might be a good idea but, you must make sure YOU CAN'T FORGET IT. Maybe hook the electric jack to the switch also so you can't hook up without turning it on.

[HowieE]

All right.

If you are seeing a deflection at each wheel the electrical portion of the brake system is OK. The fact that you see deflection in the magnet proves the system but it does not indicate the voltage being applied. Voltage is controlled by the brake controller and it the setting has been changed, reduced this may be the problem. If your controller has an amp meter apply the brakes with the manual level and note the current. The note the current when you are towing. If the current is notably less while towing the adjustment may need increasing. Max current for 4 wheels will be about 12 amps, but most systems when adjusted for the TV are set below that. On a hard brake peddle stop you might expect to see at least half of full current and have reasonable braking. If you see less readjust the controller.

Two thing will reduce braking power over time. The brakes are out of adjustment do to ware, not likely that this will show all of a sudden. The drum have a coating of rust on them from sitting too close to water for a long time. This rust acts like ball bearings on the shoes. Generally rust will ware off after a few stopping but if the coating is heavy you may want to remove the drums and sand them.

[lbdesign]

Thank you HowieE. I will be towing it a short distance in a few days, I'll play with the controller voltage settings and see what I can find. I think that if the brakes were engaging at all on my last two drives, the rust should have at least partially come off and I would have felt a change, but no such luck.
I am not really equipped for raising the trailer or getting underneath it to do any work myself. But I do feel more informed now, and am also thinking I have more options now than to drive a great distance without brakes to an Airstream dealer, since it's brakes and not, for example, sneaky leaks or a rotted floor.

[dwightdi]

If you controller has a manual override lever engage it fully when you start out. You should be able to feel the trailer brakes come on. I engage mine a couple times to get the rust off. After a few miles and 5 engagements I can really feel the difference. Then adjust my controller sensitivity for the rest of the trip. It is not only the rust on the braking diameter but the light rust on the flat surface the magnets engage that has a major effect. It is not hard to build a small ramp or use some leveling planks to pull one wheel off the ground and likely safer than jacking the whole side of the trailer.

[Wazbro]

dwightdi is right easy to do 1 wheel or even 1 axle at a time using blocks or a ramp like this one.
Amazon.com: Camco® Trailer Aid Plus: Automotive

[garry]

The way I test mine is to hook up the trailer put it in drive get up to 5mph and using the slider manual push it all the way to one side this should lock up the brakes and stop you.

If the brakes fail to stop you then the controller could be bad (not supplying sufficient voltage) or corroded wiring most likely on the ground side.

[lbdesign]

dwightdi, I did exactly that on two trips (to and from the dealer) but got nothing. Testing shows the voltage is reaching and activating the magnets. I think I need a brake mechanic.

[mimiandrews]

Rust on drums can cause a lot of wear on brake linings. It's possible that the brakes need adjusting to compensate for this. Maybe new brake shoes if the wear is excessive.