Weak brakes & battery box confusion.

[Hay Dude]

A good electric mechanic needs to dig into your battery issue. It could be the battery has a surface charge but no guts when a load is applied. It could also be an issue with how it is wired causing a repeated drain recharge cycle. Also there could be an issue with the onboard charger electronics in the box—if the box gives you messages it has a circuit board in the box.

The trailer brakes with a sudden drop off of braking power also sounds like an electrical issue. The same mechanic can check out those issues also, but if you have not, do a visual inspection of the brake wires from the plug on the trailer to each connection inside each wheel. One last point—stop running your adjust to max—you are putting lots of stress on pads and magnets by doing this.

I inspected the working. Looks good.
Running brake adjust at 7.5, not max.

 

[Gord Baker]

Remove, clean and reinstall each wire in that box, one at a time. Clean the connector terminals from the truck to trailer. A sudden change means something is wrong.
Get it professionally checked. Those small batteries are not that reliable I have found.

 

[nyone]

Get it professionally checked. Those small batteries are not that reliable I have found

It's a prety simple wire circuit that anyone can diag fairly easily..I wouldnt be giving up and taking it some where just yet.

Also those batteries can be stone dead and the brakes work totally fine because there powered by the truck not the battery.

 

[bgr]

I have a 7K trailer with dual axle brakes. Brakes were good for 6 months, then weak.
The first thing I did was chase grounds. Got a high ohm meter reading from the axles to the frame. I ran an actual ground wire from the ground connection at the trailer side of the plug to one axle and then on to the other. (The original connection was a screw to the trailer frame near the plug. It had started to rust.) Gave slack in the wire to allow for axle movement, then grounded a ring terminal to a freshly drilled hole in each axle beam. Used a stainless screw and star washer for each axle. Then covered each connection with brush-on electric contact sealer.

Brakes are now stronger than when new. I have to adjust the controller carefully so I don't overbrake on the trailer wheels. Very secure feeling to have the right braking set for a full 7K load on trailer and still have a little margin left on the controller

 

[aircommuter]

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.

I have had them come into my shop with the seal pushed out of the hub. People operate grease guns!

 

[aircommuter]

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

Maybe not adjusted correctly when you bought it?

 

[Dftodd]

I have had them come into my shop with the seal pushed out of the hub. People operate grease guns!

If the seals pushed out, then there is an issue with the seal fitting into the opening. Either wear on the inside of the hub where the seal seats, or the seal is a touch undersized so it doesn't fit snug.

 

[aircommuter]

If the seals pushed out, then there is an issue with the seal fitting into the opening. Either wear on the inside of the hub where the seal seats, or the seal is a touch undersized so it doesn't fit snug.

Not really. I have been in the repair business over 50 years and have seen it more than once, grease gun pressure can easily push out a seal. If someone keeps pumping something has to give.

 

[Dftodd]

Not really. I have been in the repair business over 50 years and have seen it more than once, grease gun pressure can easily push out a seal. If someone keeps pumping something has to give.

The grease should push through the outer bearing. If it's pushing out the lip seal instead, then there is an issue between the inner bearing and outer bearing.

The two most likely causes, either old baked up grease so it acts as a plug, or using a clay based grease which is horrible for wheel bearings.

 

[aircommuter]

The grease should push through the outer bearing. If it's pushing out the lip seal instead, then there is an issue between the inner bearing and outer bearing.

The two most likely causes, either old baked up grease so it acts as a plug, or using a clay based grease which is horrible for wheel bearings.

It also pushes through the inner bearing at the same time. They both have spaces between the rollers.