Electric Brake Issue

[Seapilgrim]

I am having a problem with the passenger side wheel on my single axle trailer overheating. The wheel and the axle are too hot to touch after only driving 12 miles. Here is some background information.
The bearings and brakes (electric) were changed last year. After a recent trip I noticed the passenger side bearing protector cover missing and upon further investigation found the hub and wheel too hot to touch. I examined the driver side wheel only to find it to be cool in comparison.
What I have done so far to find the problem:
I unplugged the electric brake controller in the vehicle. The problem still remained after a test drive.
I jacked up the trailer and spun the wheel and could not hear or feel any dragging. I then removed the wheel and hub only to find a significant amount of what appeared to be a black graphite type dust on the inside of the drum. I believe this is from the brake shoes but not sure how much is normal. The rear brake shoe appears to be wearing more than the front brake shoe. The surface of the magnetic puck is slightly worn so it appears to be making contact with the hub which I understand to be normal.

1) Why would the rear brake shoe be ?dragging? enough to wear yet is not noticeable when on the jack and spinning the wheel by hand to adjust brakes?

2) Was unplugging the brake controller the correct way to disconnect electric brakes for testing or should I have unplugged the trailer wiring from the vehicle?

Any ideas on where to go from here would be appreciated.
Thanks,
Bob

 

[maproy99]

Re: Electric Brake Issue

Well, I do know that both brakes should be about the same temperature. Do the following test.
Go for a short test drive without the trailer wiring hooked up. (Around your neighborhood and have someone follow for safety reasons)
This will prove if your issue is with the brakes or wiring.
No heat on either drum=wiring issue
Heat on the one drum again=brake issue.
Welcome to the forum!

 

[UncleWillie]

Re: Electric Brake Issue

The rear shoe does most of the work and will wear faster.
Both brakes are powered from the same wiring if the controller is Disconnected from the brakes, it doesn't matter where you do the disconnection.

This sounds like a Hot BEARING issue and not a brake problem!
Bad bearings will heat the entire drum just like a dragging brake.

 

[maproy99]

Re: Electric Brake Issue

My thought was a bearing issue or possibly his wiring could be in who knows what condition. I wouldn't put it out of the realm of possibility that he could have wires shorting, sending power to the brakes even with the brake controller removed. (And one brake has a bad connection or ground)

 

[kenmyfam]

Re: Electric Brake Issue

My money is on the bearing.........but not much of it. !!!!!!

 

[UncleWillie]

Re: Electric Brake Issue

The Brake wiring SHORTING would disable Both Brakes. They Are in Parallel.
The Controller activating improperly would activate BOTH Brakes. Same Reason.
An OPEN Circuit could disable one side in which case the Cold side would be the Bad one.
Braking on ONE Side would produce a noticeable sway in the trailer when the brakes were applied.

The OP stated that ONE hub gets hot with the Brake controller DISCONNECTED.
The only reasonable explanation is a Bad Bearing heating the hub.

 

[maproy99]

Re: Electric Brake Issue

The Brake wiring SHORTING would disable Both Brakes. They Are in Parallel.
The Controller activating improperly would activate BOTH Brakes. Same Reason.
An OPEN Circuit could disable one side in which case the Cold side would be the Bad one.
Braking on ONE Side would produce a noticeable sway in the trailer when the brakes were applied.

The OP stated that ONE hub gets hot with the Brake controller DISCONNECTED.
The only reasonable explanation is a Bad Bearing heating the hub.

I'm just saying that I would take a few minutes to do the test I said just to be 100% sure about where the issue lies. For all we know a mouse could have gone to town chewing his wiring causing 1 brake to be disconnected and another wire to short onto his brake wire. (Or wires shorting on a tow vehicle, my dog was to blame...) And the hot brake is just adjusted better causing it to grab while the other one doesn't with the limited flow of current.

 

[Seapilgrim]

Re: Electric Brake Issue

The trailer is still up on jacks so I will look at the bearings while the hub is off. My wife and I are out of town now for a few days so I won't be able to get back to it for a few. Maybe you can educate me a bit in the meantime.

Q: Is it normal for "brake dust" to be floating around within the drums and if so how much is too much?

Q: If the rear brake shoe wears more, does that mean the shoes are not centered or just that more pressure is given to the rear shoe?

Thanks for the responses so far, I'm sure more questions will arise as I get deeper into it.

I will also keep you posted as to what I find when I get home.

Bob

 

[UncleWillie]

Re: Electric Brake Issue

Q: Is it normal for "brake dust" to be floating around within the drums and if so how much is too much?
Q: If the rear brake shoe wears more, does that mean the shoes are not centered or just that more pressure is given to the rear shoe?

The Amount of brake dust all depends on how often the wheels get "dunked"and how much the shoes have worn.
The dust is just the remains of the shoes as they wear.

The rear shoe get more use due to the physics of the brake assembly.

Electric Brakes 101....



The Photo shows a Right Side Electric Brake assembly.

Magnetic Brake Actuator(A) is energized and is attracted to the inner surface of the rotating Brake Drum (Not Shown).
The Actuator moves to the rear due to friction with the rotating Brake Drum.
Brake Actuator Arm(B) Rotates on Pin(C) and forces Cam(D) against Front Brake Shoe(E)
Front Brake Shoe(E) contacts the inner surface of the Brake Drum(Not Shown) and is forced Downward due to the Braking action.
The bottom end of Front Brake Shoe(E) pushes Brake Adjustment Assembly(F) against the bottom of the REAR Brake Shoe(G).
Rear Brake Shoe(G) Contacts Inner Surface of the Brake Drum(Still Not Shown) And is forced Upward due to the Braking Action.
The Upper end of Rear Brake Shoe)G) is prevented from moving due to the contact with Pin(H).

Note:
There is no braking action if the Brake Drum is not rotating.

Cam(D) Applies pressure to the Front Shoe Only.
The Rear shoe gets the combined pressure from Cam(D) PLUS the Braking Forces of the Front Shoe. <---<<<
This causes the rear shoe to supply the majority of the braking force and to wear faster.

In reverse, Cam(D) activates the Rear Shoe and everything else happens, just backwards.

 

[Seapilgrim]

Re: Electric Brake Issue

Finally back in town and got back to this.

I disconnected both cables to each brake shoe and went for a test drive. I only had to go a few miles to find the passenger side wheel was still getting hot to the touch.
I then changed out the bearings and races on both sides of the trailer, adjusted the brakes on both sides and went for another test drive - same thing, same side with brake wires connected and disconnected.
I think the things left that could cause enough friction to heat up the same side again are the brake shoes, magnetic brake actuator, bearings (discounted as this is the second set) or the spindle?

How can I isolate it further? I have a set of plain hubs as spares which I could change out to. My total rig is 2700lbs so I wouldn?t be concerned driving without the brakes for a test but thought there might be something else to try before I go that far.
Thanks,
Bob

 

[kenmyfam]

Re: Electric Brake Issue

Hate to suggest this but how tight are the bearings adjusted. Should have a touch of play in them or they will bind and cause heat build up.
Just a thought.

 

[Seapilgrim]

Re: Electric Brake Issue

Hate to suggest this but how tight are the bearings adjusted. Should have a touch of play in them or they will bind and cause heat build up.
Just a thought.

I adjust both sides of the trailer the same. I tighten it down with a wrench and spin the wheel a few times to seat everything. Then I back the nut off with the wrench and finger tighten it down and install cotter pin. I thought along the same lines as you but figured when the driver side of the trailer is done the same way and not giving me any problems, I'm probably ok in that area.
Thanks,
Bob

 

[Josh P]

Re: Electric Brake Issue

how did u adjust your brakes? maybe back them all the way off, then drive it. Are your tires aired up to the same and are they the same size? is this a single axle or tandem? what boat is on it?

 

[bruceb58]

Re: Electric Brake Issue

Next time you take off your hubs can you post a picture of both sides? You do know there is a left and a right brake assembly right?

 

[Seapilgrim]

Re: Electric Brake Issue

Today I backed off the brake adjustment so I could not feel the slightest drag on the wheel. Test drive produced same results. Finally pulled the entire brake assembly and put on my spare hub (no brakes). I figured this would tell me if there was a spindle problem. Ran cool for a 20 mile test run. At this point I am going to replace the brake assembly even though they are only a year and a half old. Better than the axle..
Thanks

 

[Josh P]

Re: Electric Brake Issue

i would also check what bruce said make sure you have the backing plates on the correct sides. or maybe you got two lefts or two rights. did u use the same bearings from the drum brakes, or did ur extra hub have bearings with it?

 

[Seapilgrim]

Re: Electric Brake Issue

I can close this one out. Replaced the brake assemblies, made all adjustments and the issue is resolved.
Thanks to everyone for their input.