Trailer brakes

[Muleskinner]

Hey y,all. Does anyone know how to disconnect or remove the trailer brakes on my 1980 GMC Sierra 2500 4x4 truck? I don't know why but they are locking my rear brakes. I really don't need trailer brakes anyway. Thank you.

 

[bucket]

We will need a little more info, like brand of controller and whether or not it ties into the brake line.

But besides all that, trailer brakes and the controller have nothing to do with the activation of the truck brakes. You probably have another issue like faulty master cylinder, wheel cylinder issue or a shoe adjustment issue. Or a faulty rear load sensing valve, but I'm not sure those were being used yet in '80.

 

[Bextreme04]

If your brakes are locking up after you apply them(as in you press the rakes and then they fail to release after you lift your foot off the pedal) I would look at collapsed rear rubber brake line. If you are barely pressing the pedal and your rear tires are locking up, I would look at the load sensing valve.

 

[75gmck25]

Many, many years ago there used to be trailer brake systems that operated off your truck brakes hydraulic system, but they were made illegal.

Your trailer brake controller under the dash is probably either electric and connected to your brake light switch, or it’s mechanical with an actuator inside that moves forward when you stop the truck. Both of these only send power to the brake wire on a 7 connector trailer plug. They do not cause activation of the brakes on your truck.

 

[AuroraGirl]

Many, many years ago there used to be trailer brake systems that operated off your truck brakes hydraulic system, but they were made illegal.

Your trailer brake controller under the dash is probably either electric and connected to your brake light switch, or it’s mechanical with an actuator inside that moves forward when you stop the truck. Both of these only send power to the brake wire on a 7 connector trailer plug. They do not cause activation of the brakes on your truck.

The plumbed brake line from the controller to the master cylinder allowed trailer brakes to be truly proportional and to be consistent smooth lol. but i doubt this is his issue. we need pics

 

[fast 99]

Question is really vague. Please explain further.

 

[Muleskinner]

I really appreciate the many well informed answers. I am not at all knowledgeable about how a trailer brake system works on regular trucks (I understand air brakes). You are right. The controller is plumbed to the master cylinder with a wire spliced to the brake light switch. I will send pictures and I will check the items on my truck that you suggested. Also I think the truck had been sitting for a while before I bought it. The tires were pretty rotted, the power steering pump is leaking bad and I had to change the heater core; which was surprisingly easy compared to the cars that I have owned. Thank you so much for being there for old truck lovers that love old trucks.

 

[dvdswan]

Take a look at your rear brakes. You could have leaking axle seals.

Generally, brake controllers don't control the truck brakes, they are just put in line to know when pressure is applied to apply the brakes on the trailer with an electric signal.

 

[fast 99]

Need to do a good visual inspection of all 4 corners. If the truck has been sitting for a long time it may need a complete brake job. Anything from frozen front calipers to rust on the drums could cause brakes to grab. Doubt the controller is causing the problem.

 

[Grit dog]

^Agree, I can’t imagine how even an old hydraulic actuated trailer brake controller could do anything to the rear brakes.
Start in back and see what’s up w/ your drum brakes.
Since you will need to or should bleed them anyway, you can remove the brake controller hookup then and get it gone. It’s just an antique liability at this point.

 

[SirRobyn0]

Agree what other folks have said. Can't see how even an old hydraulic brake controller could cause this. It's fine if you want to remove it but you should start by inspecting the brakes.

 

[mshawn]

Electronic brake controller has nothing to do with your rear brakes on your truck, they are controlled by brake fluid. You more than likely have leak axel seal that have leaked on the rear brakes and now they are grabbing. Pull rear tires and drum and see what it looks like in there

 

[Muleskinner]

I intended to send pictures of the trailer brakes setup; but now it may be a moot point since I have broken something in the rear "pumpkin". I have yet to open the differential, (I am afraid of what I will find). I have included the pictures of the brake controller and how it connects to the master cylinder. I have also included pictures of something that I found in the back of my truck cab behind the drivers seat. Does anyone know what this is,and what would be a good caption.

 

[Muleskinner]

Which is easier, to replace broken differential gears in a rear axle still under the truck or to switch out the entire axle with another one?

 

[Turbo4whl]

You must be registered for see images attach

These look like old road flares. Probably got wet. Still may be flammable, be careful.