Trailer Brakes Too Weak

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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These are more your issue. See the circled area

77582ed58904ff8a65cfa2b3d80d072c.jpg
 

OleBlackyLBZ

Active member
May 22, 2020
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Yep replacing those with heat shrink type. This is the old main wire vs the new 12ga stuff.
 

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jlawles2

Well-known member
Jan 28, 2010
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Danbury, TX
You might try taking the shoes off and cleaning them to get most of the grease off / out, then light them on fire (saw this done on youtube by a farmer on his class 8) and let the grease cook itself out of the shoes. Once the fire puts itself out, clean again.

And those blue connectors are most likely your issue. Pull one first, check voltage there. The 7 way wire was probably OK. Too small of a wire will heat up quicker than the bigger wires. Since most brakes are not full voltage for very long, that is why they tend to run smaller wire.
 
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660catman

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May 18, 2021
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Agree with what’s been said about the blue connectors. They are a temporary fix IMO for repairs on the road.


2013 Sierra SLE 2500HD Crew Cab
 

OleBlackyLBZ

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May 22, 2020
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We ran bigger 7 wire, and we are cleaning up everything as we go and making sure all wires are big enough, changing to sealed connectors, should finish all that tonight.. then this weekend ima clean up all the hubs, pads, and magnets and repack the bearings by hand. If that does not help ima be stumped.
 

Ron Nielson

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Oct 11, 2009
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If you THINK your magnets need to be replaced, see if there is a magnet from a higher capacity axle that will fit your brake setup. My factory brakes were 5400 lbs, I updated the magnets to 7000 lb magnets. Now that's not as good as replacing my 5400 lb axles with 7000 lb axles, but you do get more braking power.
 
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OleBlackyLBZ

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May 22, 2020
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We got the new 12 ga wire in lasnight with new water tight connectors. But we are still only getting 8.8-9.3 volts at the brake wire when the brake button is pressed. So we traced it all the way to the plug, we are definitely getting 13 volts at the truck, checked that multiple times. But we noticed as soon as we plug in the trailer main line that its dropping to 10.5v even at the plug itself. So Im losing about 1.5 volts from the plug to the brakes which is fine, I just cant figure out why the voltage drop right there at the plug soon as we plug in. Is it possible the insides of the plug are too small?
 

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juddski88

Freedom Diesel
Jul 1, 2008
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We got the new 12 ga wire in lasnight with new water tight connectors. But we are still only getting 8.8-9.3 volts at the brake wire when the brake button is pressed. So we traced it all the way to the plug, we are definitely getting 13 volts at the truck, checked that multiple times. But we noticed as soon as we plug in the trailer main line that its dropping to 10.5v even at the plug itself. So Im losing about 1.5 volts from the plug to the brakes which is fine, I just cant figure out why the voltage drop right there at the plug soon as we plug in. Is it possible the insides of the plug are too small?
What is the resistance of the trailer brake circuit?
 

OleBlackyLBZ

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May 22, 2020
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What is the resistance of the trailer brake circuit?
Im not sure how to find this out^. However we did hook a LML with a built in controller up to the trailer and got 11 volts to the brakes. Then after that we hooked up a 05 LLY with the exact same quest controller that I have and got 8.5v again. The guy with the LLY says he has no issue squalling the trailer tires while towing empty trailers if they have good brakes.
 

OleBlackyLBZ

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May 22, 2020
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The good news(or bad) is that everything needed replaced. The magnets were well greased and had slid grooves in the hubs as well as the magnets. Everything was very uneven and ruined in my opinion, the brakes/magnets couldnt have been working hardly at all. $1,000 later I have complete new backplate assemblies and new hubs with new bearings. I think it will be much much better in spite of only 8.5v to the brakes. I will get everything finished up in the morning and post results.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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The good news(or bad) is that everything needed replaced. The magnets were well greased and had slid grooves in the hubs as well as the magnets. Everything was very uneven and ruined in my opinion, the brakes/magnets couldnt have been working hardly at all. $1,000 later I have complete new backplate assemblies and new hubs with new bearings. I think it will be much much better in spite of only 8.5v to the brakes. I will get everything finished up in the morning and post results.

I’ll bet they work awesome now. You also now eliminated any future issues with all the work you did on the wiring. That’s what I’ll be doing on my flat bed in the coming months
 

Hoser

Active member
Jun 19, 2016
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lol, oops, answered the question about what those connectors were before I saw there was a second page of posts. . . . .

Those are wire connectors. Insert the wires, then squeeze the oval pad with the raised hump and it pierces the insulation. They are fancy “scotch locks”. Those look like good ones and they may even be filled with grease to keep the connection somewhat water proof.
 

jlawles2

Well-known member
Jan 28, 2010
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Danbury, TX
Depending on how your controller is set, it may not be pushing full voltage when the trailer is connected. With no load, the controller pushes full voltage, but there is nothing there to absorb it, so it stays up.

Check your truck side plug for proper tension and corrosion on the lugs. They may look clean, but actually be slightly covered in corrosion (like aluminum powder).