I need help with a trailer brake problem

[rickhans]

My 25' gooseneck 16k GVW brakes do very little good, although they did the day I towed the trailer home. But it seems since I first towed a heavy load, the have not done much. I have followed other threads on brake controllers and trailer brake adjustments and done some testing on my system.



First with the brakes fully applied and the axle jacked up, I can turn the wheel by hand. With the brake released, there still feels like a little drag, about like a cars, so I have not adjusted them. About the same time, I noticed the same problem with an older trailer of mine which probably does need adjusting.



I checked voltages. Without the brakes attached to the truck, and the engine off, I get 11. 7 volts at the plug when brakes are applied fully. With the trailer brakes hooked up, I get a 5. 7 volts at the plug and at the brakes, no matter where the slide bar is sitting, and no matter where I adjust the 2 rheostats to. The controller is a Hayes Kelsey unit installed in 1998. I talked to Hayes and they said it should put out more voltage, that it is probably a wiring problem. I think, however, that if it was, I wouldn't get 11. 7 V at the plug, and I would think that a 6 V drop when applying the brakes would be too much.



I talked to a trailer shop and they said that that is a poor controler, to put in a DrawTite solid state controller.



Then I read another thread that talked about voltages and 5 to 6 volts was working just fine on another members trailer.



Can some of you give me some technical info on this subject so I can have better brakes? It is wired with 12 Gauge hot and ground wire to the brakes.

 

[RustyTRanch]

To rule out your trailer brake get another 12v suppy and put it to the connection on the trailer. This should lock the wheel up

If it doesn't you could have brake problem on trailer

(check your wires from plug to brakes )

If it locks up then you have controllor problems

just a thought

later

mike

 

[Dieselnerd]

B'Gate, that dragging you hear that makes you think the brakes are adjusted out to the drums is the magnet. The magnet rides against the armature, there is no air gap. It fooled me the first time I heard it a few years back. I also checked with the tech support people at Dexter and they assured me the magnet was supposed to be in contact with the drum at all times. So your brakes should be adjusted first. Dexter says after the first 200 miles and every 3000 thereafter. Second, check the ground connection on your trailer, the ground completes the circuit and is often the culprit when you have weak brakes. Clean the frame where the ground is connected and if there isn't a starwasher under the connector, add one. Do you have a breakaway switch on the trailer? Jack up the wheels, pull the breakaway. Turn the wheel by hand and it should lock up in about 1/16 of a turn. If it goes 1/4 of a turn or more your brakes are way out of adjustment. If the ground is good and the current (not voltage) is good and they still won't lock up properly, you probably have grease on the linings. The Dexter website has a lot of good info on brakes. http://www.dexteraxle.com/

 

[Turbo Thom]

B'Gate:

Ron is right about the ground. It controls everything. I was camped next a gentleman in Nashville a while back and he had a problem with his lights on a towed vehicle behind his motorhome. They would always be dimmer than his MH. The brake lights would not work at all. I explaned to him about the importantance of the ground. I found out he was grounded through the towing hitch. I talked him into runnin a wire for the ground from the RV to the dinghy. Guess what! Every thing worked right. He just stood there and stared at me. He didn't understand the ground.



First thing I would check is all wiring. Then a good ground as Ron said. Make sure the ground connection at the plug is tight. There is a possibility a wire could be crossed at the control since you have had this problem with other trailers. I have had wiring connections grow cold and loose voltage.



This may not fix your condition but is a few things I have to check.



Good luck.

Preston

 

[rickhans]

I'll do the brake test using the break-away switch and see what happens. The ground wire is a 12 gauage wire that attaches to the center of the plug. The truck came with the trailer tow kit with factory wires for the brakes that the installer tied into. I assume that the truck has a continuous ground back to a common ground point somewhere at the front. Surly they don't use the mounting bracket for the plug as the ground, do they?



I don't have anyway to put an ammeter in line with the brakes to see how many amps they are pulling. From my experience in electronics, I should be able to track down a problem using voltage. However, to do so, I need to know what the normal voltage drop is when the brakes are applied. I get 5. 7V at both brakes. The brakes are in parrallel. I suppose I could disconnect one side and see if the voltage goes up on the other side. I am basing my info on Hayes customer service who said that 5. 7 is too low, that I should be getting 12V with the brakes applied. Does anyone know if they are wrong?

 

[Dieselnerd]

B'Gate, the trailer should have it's own ground wire, it doesn't get its ground from your plug. The breakaway switch makes a complete brake circuit with no connection whatever to your truck. That's the nice thing about using the breakaway switch, if your brakes still don't work you have eliminated the truck as the problem. I am assuming you have a 12 volt battery in the trailer that operates the brakes in a breakaway situation. If you don't that can also be part of the problem and probably illegal since the trailer is supposed to stop if it breaks loose. I've worked on a lot of electric brake problems over the years so if you have more questions don't hesitate to ask. A lot of the members are long time trailer haulers and I'm sure they can help too. Believe me, when the electric brakes are set up properly, your truck will stop as good as or in some cases better than just the solo truck.

 

[rickhans]

As I said earlier, I am going to do a test using the break-away switch.



However, the question I need answered concerns the voltage issue. I can not determine if my brake controller is acting properly until I can find out if 5. 7V is the correct voltage. I don't understand how there could be a 6 volt drop across the magnets, but maybe that is normal. Does anyone know about voltages and brake controllers?

 

[Turbo Thom]

B'gate:

I can't answer for Kelsey-Hayes but if you want I can give you the no of Tekonsa and the person to speak to.





Preston

 

[Eric_77]

Your voltage should be the same w/ or w/o trailer hooked up. Somewhere you have a short or too small of wire for the amp load you are sending to brakes.

 

[Lug-nut]

Eric-77 makes a good point. You say that the hot lead to the brakes is 12 gauge. I would have to check, but that sounds a little on the small side to me. I believe mine is at least 8 gauge. Just guessing here, but you might want to check it out.

 

[rickhans]

12 gauge wire is the standard size for electric brakes. I have already checked into it. 12 gauge wire is rated to carry 2400 watts or 200 amps at 12 volts, or 20 amps at 120 volts. The other requirement, as I mentioned earlier, is that a 12 gauge ground wire be run from the brakes back to the plug. What I don't know is if DC pre-wired the brake controller wire using 12 gauge. I would presume it did since that is the standard. If anyone knows otherwise please post it.

 

[Paul Somers]

Voltage measured accross magnet should read 0 no brakes applied and close to 12 volts with break away pulled out. At 5. 7 volts I would not think you should be able to turn wheel. My guess is over greasing to the point of pushing grease pass rear seal into drum area. Grease on magnets and brake shoes make for poor brakes. Also check adjustments.

 

[Snowbird]

B'Gate, I agree with Paul Somers above. Also try by-passing your brake controller right at the controller itself. This would be the quickest way tell if you need a new brake controller. To do this, disconnect the 12 volt supply to the controller (usually black) and the controller output wire to the trailer brakes (usually blue). Then just temporary twist the wires together so that you are applying full power to the trailer brakes. If your trailer brakes are now fully on, then your controller is bad. Don't leave the wires connected any longer than necessary because of the heat built up that will occur at the wheel brake magnets.

 

[Ron Bissett]

Warning do not , pull lanyard for brake a way with truck plug in to trailer . It can and will some times fry the controler . All most problems with brakes start with dirty coroded pins in cord or receptical . Clean with contact cleaner , or as I use viniger and salt mix ,dip wait one min flush with clean water dry air best , then blast with WD 40 let dry , do it one more time ,then try it. wire lead batt charge 8 guage most all other 12 guage . Hope this helps . LOL Ron in Louisville KY

 

[Paul Somers]

Good point Ron. Really never thought about that but it makes sense. What you would be doing is shorting to ground the out put of the controller. When I pull mine it isn't hooked to tow vehicle. I check my brake wiring erery time I pack wheels by pulling break away cable.

 

[Loren]

B'gate,



Sorry I can't help you with voltage readings, but I can clear up some errors.



Most important... 12 gauge wire is rated to carry 20 amps no matter what the voltage. If you attempt to make it carry 200 amps at 12 volts you will melt the insulation as a minimum. I'd be surprised if you didn't also melt the copper wire itself. 200 amps is welding current. You've seen the wire sizes welders use.



Second, the center contact of a standard 7-wire trailer plug is not the ground. This would be too logical. The ground is on pin #1. If you take the cover off the plug (not the receptical), you can find the numbers in the plastic. Pollak, the company that seems to have set the standard for trailer plugs, recommends a 10 gauge wire for the ground. You are correct, pin #2 (electric brakes) requires 12 gauge wire.



My suggestion is one you've seen here already. The first thing I'd do is adjust the brakes. The second is to try the break-away device to see if it locks your brakes. If the break-away won't lock the brakes either, it's probably not your controller.



I know you want to work with voltages, but the little bit I've read on electric brake troubleshooting seems to use current as the way to see if the brakes are working correctly or not. Obviously if they are drawing sufficient current and still not stopping there is something wrong inside the hub. At least they are relatively easy to work on and the parts are cheap compared to truck parts.



Good luck.



Loren

 

[rickhans]

You are right about the amps. That was kind of dumb of me. I converted wrong and wasn't thinking. I use 120 amps for welding and know exactly what you are saying.



However, on my trailer, the ground wire is attached to the center poll of the plug. I have checked it with an ohm meter and the center is grounded. I don't know if center of the reciever part of the plug is grounded through the frame or has a wire on it. I will check it out.



I talked to a shop in Washington that specializes in trailer brakes and trailer repairs. They said that 5. 7 V is normal and that the Hayes Kelsey controller is a good unit because it increases the amps the harder you are stopping (decellerating). It does this via a free-swining arm (I forget what he called it) inside the controller that rotates from decelleration force.



He said the same thing that has been said here, that probably the brakes need adjusting. He said that many times when the axles are built, the brakes are assembled and not adjusted, leaving that to the trailer manufacturerer, but that quite often, they fail to adjust them. I plan to adjust them the next time I have the trailer hooked up. Thanks for all the responses.

 

[Turbo Thom]

B'Gate

I know this horse has been ridden pretty hard and I don't want to beat it while it's tired but if the center pin is ground where is the back up lights pinned? When one is wire moved from its primary location another has to been shifted also. If you look at the receptical with the door open, the lower left is blade the ground. All trailers are wired the same so you will be able to pull any trailer you want without worring about the lights.



I pull 4 different trailers and all work correctly and I can hook up to any fifth wheel with a 7 blade connection and go without concern.



To keep things compatible, I would keep all plugs typical for that reason.



I have a little 16 foot utility trailer I loaned out and when I got it back, I was 45 miles from home and none of the lights worked. He had changed everything to fit his truck. Never did he get one of my trailers again. .



Just something to think about.







Preston

 

[rickhans]

Thanks for the input. I own several trailers and have been towing for around 30 years and have had only one trailer with back up lights on it, and I never figured out how to make them work. I have never heard of a pin on the plug driving backup lights until now. The receiver plug on my truck was installed by a trailer dealer and that trailer did not have back up lights. The gooseneck I have now does not have backup lights and was wired by probing the receiver plug with a volt meter to see how it was wired.



Obviously, I will have to find a standard pin-out diagram and then re-wire my hookups on the truck and trailer. Although the trailer tested to have a good ground, it may not be good enough.

 

[jolyman]

I have been reading the posts on the brake controler problem with interest. Would someone post the correct pinouts for the plugs???



The local trailer store has a pinout in their brochure that is completely different than what DC used when they wired my truck. I don't rember their pinout but I wired my camper to match the truck (one pin is used to charge the camper battery) and I would like to check to make sure that mine is STANDARD.



Thanks -- as always interesting.