Electric brake testing on old trailer

[adjusterr]

old style electric brakes are rather simple, basically, a magnet activated by the amount of electricity applied through a rheostat type brake controller. I bet if you pull the drums and clean the contact surfaces, the brakes will work. You will need to insure the brake shoes are free to move when activated. I have had electric brakes on many trailers, including a 9800. lb tandem dump trailer and they work perfectly. The only thing you must do is regulate the dash mounted brake control for the weight of the load, too much electricity and you will slide the tires etc. Good luck.

 

[sailorman]

Very good points made by all here so I won 't try to reply to each individually. I am gonna pull the drums first to see if I have anything to work with and then take it from there. Being educationally in-expereienced about electric brakes some questions bother me a lot. When controller is installed how does it know to work when I hit truck brake peddle ? Do have to find a wire somwwhere in truck for controller to sense the brake peddle ? I have 4 wire plug now and its been pointed out I need a 5 th to operate brakes. But where does the 5th wire come from in the truck/controller ?

 

[radioman]

Very good points made by all here so I won 't try to reply to each individually. I am gonna pull the drums first to see if I have anything to work with and then take it from there. Being educationally in-expereienced about electric brakes some questions bother me a lot. When controller is installed how does it know to work when I hit truck brake peddle ? Do have to find a wire somwwhere in truck for controller to sense the brake peddle ? I have 4 wire plug now and its been pointed out I need a 5 th to operate brakes. But where does the 5th wire come from in the truck/controller ?

sailorman start here and read up on the brake wiring subject.

Help Articles | etrailer.com

 

[sailorman]

sailorman start here and read up on the brake wiring subject.

Help Articles | etrailer.com

Thanks radioman. Bookmarked for reading as I enjoy evening rum and cokes.

 

[not2old]

I'm not sure you can just put 12V to an electric brake. Brakes take controlled current as input - usually 0-20A, not voltage. If you apply a straight 12V, you are providing virtually unlimited current - limited only by the impedance of the wire. I don't know what the effect would be.

JayC

It will be able to take all current available as that is what the break-away switch provides. There is nothing except a switch inside that little box.

 

[mjw357]

When controller is installed how does it know to work when I hit truck brake peddle ? Do have to find a wire somwwhere in truck for controller to sense the brake peddle ?

Brake controllers are actually very easy to wire up. They usually only have four connections. A hot wire for power, a ground, a wire that connects to the brake light switch, and an output wire that goes back to the trailer brakes. That's where your 5th wire comes from on the 5-pin plug.

Get a quality inertial type brake controller, they are much easier to set up and use. Tekonsha makes some good ones.

 

[sailorman]

Brake controllers are actually very easy to wire up. They usually only have four connections. A hot wire for power, a ground, a wire that connects to the brake light switch, and an output wire that goes back to the trailer brakes. That's where your 5th wire comes from on the 5-pin plug.

Get a quality inertial type brake controller, they are much easier to set up and use. Tekonsha makes some good ones.

I was hoping that was where the mysterious 5th wire went. Its been a long time since I looked at a brake light switch. Is it still a mechanical thing that contacts the brake arm peddle in some way ? I 'm not real excited about removing my 4 pin plug from truck. Could I just run the 5th wire to back of truck with a plug pin on it, run a similar wire from trailer brakes, plug in 4 pin plug for lights and separate 5th wire for brakes ? I 'm sure I 'm missing something here due to my lack of controller knowledge. Gonna do some reading on it tonight with the link Radioman provided. Hope they got pictures.

 

[mjw357]

I was hoping that was where the mysterious 5th wire went. Its been a long time since I looked at a brake light switch. Is it still a mechanical thing that contacts the brake arm peddle in some way ? I 'm not real excited about removing my 4 pin plug from truck. Could I just run the 5th wire to back of truck with a plug pin on it, run a similar wire from trailer brakes, plug in 4 pin plug for lights and separate 5th wire for brakes ? I 'm sure I 'm missing something here due to my lack of controller knowledge. Gonna do some reading on it tonight with the link Radioman provided. Hope they got pictures.

Well on a Ford I believe the brake switch is actually controlled by pressure in the brake lines, a pressure switch. You might want to find a Ford truck forum and get some input from there. Anyways there should be two wires to the switch, one hot all the time and the other that is hot when the brakes are on. That's the one that goes to the brake controller.

And K7LN brings up a good point, no such thing as too good of a ground. You can do like you are saying if the budget is really that tight. You can make an extra ground by attaching a heavy wire to the frame of the trailer and connecting an alligator clip to the other end, so you can just attach it to your bumper or something as an extra ground.

 

[Diamondpilot]

You can wire it any way you want but it will be a little odd. I would just use the standard 7 pin round plug. That way your trailer could be pulled safely by any truck. Its the standard now days. As for your 4 flat plug just leave it and wire up both. Most bigger Fords come that way, with both a 7 round and a flat 4

Most late model truck are plug and play for brake controllers. Not sure about yours but look into it.



Chris

 

[sailorman]

You can wire it any way you want but it will be a little odd. I would just use the standard 7 pin round plug. That way your trailer could be pulled safely by any truck. Its the standard now days. As for your 4 flat plug just leave it and wire up both. Most bigger Fords come that way, with both a 7 round and a flat 4

Most late model truck are plug and play for brake controllers. Not sure about yours but look into it.



Chris

Thanks Chris. I want to do it the right way. If its worth doin', its worth doin' right. Not gonna worry about savin' a buck. Done a little research and if I understand correctly there is an adapter kit to go from my 4 flat plug to a round 7 or 6 pin. Silly me didn 't realize ahead of time that trailer had electric brakes ( wires were cut off short and taped ) when I installed all new running and brake light wiring. I put a flat 4 on trailer. Guess I 'll have to change that to a round 6 or 7 to include brake stuff. Shouldn 't be too expensive. Does that make sense :confused2: ? Heck, for all I know when drum is pulled the previous guy may have removed all of the brake guts !

 

[Reg]

I inherited a small 1973 Tag-A-Long travel trailer. It appears as though it was rigged for electric brakes. There are two wires ( cut ) coming out of each of the well drums( total of 4 wires ). How might I test to see if the brakes still function before buying needed vehicle controller and wiring system ? Could I just use a 12 volt battery on the 2 wires ( + and - ) to see if brakes engage ? I havent 't yet pulled drums to see what braking system might be there. I 'll be towing with a ford ranger XLT pickup so I 'd like to restore brake function if possible. I 'm also gonna add a weight distribution sway control hitch system if that matters.

Yes, that works.
Anther thing is a battery charger - especially one with an ammeter.
Each brake coil should draw about 3 amps.
If you have to go in there and WORK on them DO get self adjusting backplates.
Rockland auto has the Dexter units for something like $5 or $6 more than the non self adjusting ones - WELL worth the money to save the aggravation of having to adjust them again and again.

 

[Diamondpilot]

6 pin round plugs are 80's tech. If you are going to do it do it to todays standards and get a 7 pin plug.

Chris

 

[sailorman]

6 pin round plugs are 80's tech. If you are going to do it do it to todays standards and get a 7 pin plug.

Chris

Probably will do 7 pin as soon as I gain an understanding of what each pin is for. Ya might have guessed wiring is not my high suit. I'm thinkin' 4 wires are for brake lights, turn signals, and stop lights ( maybe ground ) and the other 3 are for ground, power and trailer brakes.

 

[jwstewar]

The seven wires are left turn, right turn, tail light, ground, brakes, 12v for battery charge, and though rarely used back-up lights. My Chevys actually have them wired up from the factory. Our old camper even had back-up lights - and they worked - once I put new taillights on.

 

[sailorman]

Thanks all you guys ! You 're making my research easy 'cause ya 'll are doin' it for me when I don t know where to look. Thanks K7LN for the wiring diagram and jwstewar for explanation of 7 pins. It made something click in my mind.

 

[wvpolekat]

As Chris has said, do the world a favor and wire it up standard. Nothing more irritating than hooking a trailer up and having to figure it all up and make adapters. Standards are there for a reason. 7 pin connectors are cheap.

 

[Reg]

As the old saying goes; "Standards are SO much fun, everyone seems to have different ones."

ONE of the big differences to watch out for with trailers is the switch around between back-up light wire and brake actuation wire.
Boat trailers typically DO NOT have electric brakes, they have surge brakes.
Campers typically DO have electric brakes and many folk want a wire for back up lights and another one for aux battery charging.
If the brakes come on HARD when you try to back up you probably have the RV/Boat switcheroo.

I figure;
Left, right turn, brake lights (2 between them).
running, brake actuation, 12+, aux 12+, ground.
Although brake actuation is USUALLY blue don't count on it with a trailer that you don't KNOW the history of. Same with all the other wires, check them by FUNCTION and NOT by wire color.

 

[adjusterr]

I noticed you are towing with a Ford Ranger but you didn't indicate what year. If relatively new, you can get an adapter plug and wiring at most any auto parts store, it simplifys 7 pin plug hookup, instructions come with it, find wiring harness junction, located in rear bumper or frame area, unplug harness, insert "T" adapter, plug all back together, mount your 7 pin plug, takes minutes. Good luck.

 

[sailorman]

I noticed you are towing with a Ford Ranger but you didn't indicate what year. If relatively new, you can get an adapter plug and wiring at most any auto parts store, it simplifys 7 pin plug hookup, instructions come with it, find wiring harness junction, located in rear bumper or frame area, unplug harness, insert "T" adapter, plug all back together, mount your 7 pin plug, takes minutes. Good luck.

Thanks for the tip. I 'll look into it. Ford Ranger is a 2003 XLT.

 

[sailorman]

Attempting to post brake picture after removing one drum today