Weak brakes & battery box confusion.

[Hay Dude]

Noticed trailer brakes are weak.
Battery box says “recharge” on battery, but battery is only 2 months old and electrical tester reads 12.4V
Brakes work, but don’t do a lot, even with brake controller fully cranked to 10.
The trailer is only a year old and brakes worked well when I first got it.

What should I start looking at? Wiring connections seem fine

 

[LittleBill21]

little confused, power for brakes are supplied by the 7pin, connected to the truck, through the brake controller, the battery onboard is for emergency pin pull.

most trailer brakes are manual adjustment, have they been adjusted?

 

[Hay Dude]

Yeah should have been more clear: there’s 2 issues
1. Battery box says “recharge” but tester says 12.4V
2. Brakes weak.
No, they haven’t been adjusted, but what would have changed that much from using it for a few months? It only gets used 2x per week. May have used it 15 times since I brought it home in March. The braking power dropped suddenly

 

[LittleBill21]

i don't know what a battery box is, your going to have to explain.

too tight brakes can get burned and wear quickly, other issue, is you had a grease seal leak, and the brakes are coated in grease, especially if they were greased using zerks and done improperly.

 

[dieselscout80]

I would look at the wiring for bad spots especially where the wires go into and out of the axle tubes.

 

[Hay Dude]

i don't know what a battery box is, your going to have to explain.

too tight brakes can get burned and wear quickly, other issue, is you had a grease seal leak, and the brakes are coated in grease, especially if they were greased using zerks and done improperly.

A trailer battery box is a small plastic box on the tongue of the trailer that contains a small 12V gel battery to actuate the brakes if the trailer becomes disconnected from the vehicle. It has “test” buttons you can push on the lid to provide information on battery status.

 

[LittleBill21]

A trailer battery box is a small plastic box on the tongue of the trailer that contains a small 12V gel battery to actuate the brakes if the trailer becomes disconnected from the vehicle. It has “test” buttons you can push on the lid to provide information on battery status.

well idk what voltage it deems rechargeable, is this battery charged when the 7 pin is plugged in? 12.4 is a touch low, not recharge low.

 

[Hay Dude]

Trailer battery box.

 

[LittleBill21]

thats fancy, make sure its charging. plug into the truck with it running make sure its over 13 v at the battery terminals

 

[Dftodd]

i don't know what a battery box is, your going to have to explain.

too tight brakes can get burned and wear quickly, other issue, is you had a grease seal leak, and the brakes are coated in grease, especially if they were greased using zerks and done improperly.

How do you grease an axle wrong with a zirc fitting??

If you just do 6 pumps of grease, fresh grease will never reach the outer bearing. There's a minimum of a 1/4 tube of grease capacity inside the hub between the inner and outer bearing on a 3500lb axle.

Excess grease will ooze out the outer bearing into the cap. So there shouldn't be much of a chance to build up enough pressure inside to force the grease past the lip seal.

I could see a failure if whomever installed the lip seal put it in backwards or lost the spring out of it.

But if the lip seal is installed correctly, then you can pump grease till your hearts content and it won't push past that lip seal and effect your breaks.