Electric Brake Troubleshooting

[CarefreeLad]

Hi All,

Well I finally got my Primus HQ brake controller in my Nissan Frontier (mid-sized), but no obvious braking felt.

What I do know is this:

1. The brake controller shows signs of all clear - everything functions as it should - no error codes
2. Using the manual button on the controller (as in for trailer sway or other emergency situations) makes an electric motor sound at each of the wheels
3. Using the brake pedal makes the same electric sound at each wheel
4. I drove and would hit the gas and then feet off pedals I'd use the manual button to apply the trauiler brakes - di not seem to slow at all while coasting. I tried jacking the main setting up to 13 volts and used the highest boost option - nada. I would have expected the brakes to lock up under the full voltage/boost scenario.
5. This trailer has not had the electric brakes used for at least 2-3 years

If I had to guess I'd say the brakes are frozen and the electric motor can't move them, but as I'm inexperienced with electric brakes I figured I'd see what the experienced have to say

I assume that the mechanical aspects of the drum brakes are the same as any other brakes, but hydraulics are replaced by an electric motor at each wheel. So I get brakes in general, but not sure how the electric vs hydraulic may change diagnosing no feeling of braking.


Thanks in advance

-Bryan

[stevebaz]

Put the trailer on jack stands and have someone hit the brake controller for you while turning the tire. The brakes may need adjusting. I once had the same problem. took the tire and drum off and the brake shoes were not there. I found out they were made from unobtanium. I had to replace the whole brake system with a set from another manufacturer.

If you have 7" diameter drums don't expect a whole lot of brake power on pavement they will slow you down but wont skid you to a stop unless the trailer is very light.

[Byron Kinnaman]

I don't believe there a "motor" involved but there is electro magnets. Do a google search on electric trailer brakes or go to https://www.dexteraxle.com/resources...lectric-brakes
and watch the video.

[CarefreeLad]

Originally Posted by stevebaz

Put the trailer on jack stands and have someone hit the brake controller for you while turning the tire. The brakes may need adjusting. I once had the same problem. took the tire and drum off and the brake shoes were not there. I found out they were made from unobtanium. I had to replace the whole brake system with a set from another manufacturer.

If you have 7" diameter drums don't expect a whole lot of brake power on pavement they will slow you down but wont skid you to a stop unless the trailer is very light.

Thank Steve - Nice Captain America/Avengers reference!

Interesting that you say they won't skid - so many brake controller sites and the instructions that came with them say that they should be able to lock up the tires on the trailer. My settings were for a trailer probably 3 times the weight of mine and couldn't feel anything when applied (of course due to whatever is up with the brakes). I know the truck won't skid, but everything I've read said the trailer wheels can lock up.

Jack stands and a looksee it shall be - like you said...maybe the shoes walked off


Thanks!

[CarefreeLad]

Originally Posted by Byron Kinnaman

I don't believe there a "motor" involved but there is electro magnets. Do a google search on electric trailer brakes or go to https://www.dexteraxle.com/resources...lectric-brakes
and watch the video.

Thanks Byron - I should have stuck with "electrical buzzing sound" "Motor" kind of felt wrong here - now I know!

[John in Michigan]

Yes, I agree with stevebaz's recommendation to put the trailer up on jack stands, then have someone press the brake while you try rotating each wheel. Pressing the brake pedal should immediately stop the wheel FIRMLY so that you can't turn the wheel with any amount of strength.

- The fact that the vehicle did not slow down or stop when pressing the manual override braking button while coasting at very low speed suggests that either the brakes need to be adjusted or the shoes are worn out.

- The fact that you are hearing a sound at each brake when the brake pedal is pressed suggests that the brake magnets are working.

[Byron Kinnaman]

Originally Posted by John in Michigan

Yes, I agree with stevebaz's recommendation to put the trailer up on jack stands, then have someone press the brake while you try rotating each wheel. Pressing the brake pedal should immediately stop the wheel FIRMLY so that you can't turn the wheel with any amount of strength.

- The fact that the vehicle did not slow down or stop when pressing the manual override braking button while coasting at very low speed suggests that either the brakes need to be adjusted or the shoes are worn out.

- The fact that you are hearing a sound at each brake when the brake pedal is pressed suggests that the brake magnets are working.

With a prodigy brake controller it will do no good to press the brake pedal. You'll have use the manual over ride.

I suppose it's possible that the brakes need adjusting. Take it to a utility trailer shop and have them adjusted, while there you might have them repack the bearing.

[Raspy]

As a first attempt, adjust the brakes to the point they are just starting to drag. This is a simple procedure that will help you troubleshoot with no cost. It may help, but I doubt it.

You may hear a faint humming with the brakes applied and the wheel not turning, but if the wheel is turning, there will be a scraping sound as the magnet rubs against the drum to energize the shoes. They will hold much better rolling forward than backward.

If you hear no obvious scraping when the brakes are applied, and no apparent braking force, it's time to pull the drums off and have a look. Beyond this point it could be a number of things and it might just be that the linkage is stuck. Knock it loose with light taps of a hammer, but use no oil. See if the shoes look good with about 1/4" of lining.

Brakes will gradually get stronger and stronger as they wear in. So they may not skid in the beginning, but they will later, after some use. Mine would not skid when new and now I have them turned down to about 1/2 power to keep them from skidding.

If you pull the drums and find an obvious problem, it is probably best to just replace the whole pre-assembled backing plates, and start fresh. Make sure the braking surface in the drums is not grooved and that the side of the drum, where the magnet rubs is smooth and undamaged. The drums can have surface rust and that is fine, just clean it up with sand paper or steel wool.

After you get to that point, it's time to inspect and pack the bearings and replace the inner seals. Clean the spindles including the area where the seals run. Tighten the spindle nuts as per specs and lock them in place with the cotter pins. Install the caps. Road test and go camping.

[CarefreeLad]

Originally Posted by John in Michigan

Yes, I agree with stevebaz's recommendation to put the trailer up on jack stands, then have someone press the brake while you try rotating each wheel. Pressing the brake pedal should immediately stop the wheel FIRMLY so that you can't turn the wheel with any amount of strength.

- The fact that the vehicle did not slow down or stop when pressing the manual override braking button while coasting at very low speed suggests that either the brakes need to be adjusted or the shoes are worn out.

- The fact that you are hearing a sound at each brake when the brake pedal is pressed suggests that the brake magnets are working.

Thanks John - I've come to the same conclusion - positive signs of life (magnets appear to be engaging), but some investigation needed (shoes need adjustment or replacement). Weather will be nice this week so off comes a wheel to see what's what!

[CarefreeLad]

Originally Posted by Raspy

As a first attempt, adjust the brakes to the point they are just starting to drag. This is a simple procedure that will help you troubleshoot with no cost. It may help, but I doubt it.

You may hear a faint humming with the brakes applied and the wheel not turning, but if the wheel is turning, there will be a scraping sound as the magnet rubs against the drum to energize the shoes. They will hold much better rolling forward than backward.

If you hear no obvious scraping when the brakes are applied, and no apparent braking force, it's time to pull the drums off and have a look. Beyond this point it could be a number of things and it might just be that the linkage is stuck. Knock it loose with light taps of a hammer, but use no oil. See if the shoes look good with about 1/4" of lining.

Brakes will gradually get stronger and stronger as they wear in. So they may not skid in the beginning, but they will later, after some use. Mine would not skid when new and now I have them turned down to about 1/2 power to keep them from skidding.

If you pull the drums and find an obvious problem, it is probably best to just replace the whole pre-assembled backing plates, and start fresh. Make sure the braking surface in the drums is not grooved and that the side of the drum, where the magnet rubs is smooth and undamaged. The drums can have surface rust and that is fine, just clean it up with sand paper or steel wool.

After you get to that point, it's time to inspect and pack the bearings and replace the inner seals. Clean the spindles including the area where the seals run. Tighten the spindle nuts as per specs and lock them in place with the cotter pins. Install the caps. Road test and go camping.

Thanks for the troubleshooting steps - a few things I forgot about since the last time I played with drum brakes....about 25 years ago I can finally use that spring releasing tool again after all these years!

[swhird]

I did what stevebaz is recommending and had to adjust the brakes on my Casita. I received it new from the factory with the brakes completely loose such that they did not break at all. I adjusted the star wheel adjustment to the point where the brakes just made contact and then backed it of a couple turns. I did this with the wheel jacked up so I could spin it. You will need safety blocks if you do this because the adjustment requires one to get under the trailer. This worked well.

[jim hol]

Hi John, My trailer brakes only lock up when stopping below 5mph, like when stopping at a stop sign. I tried to correct this problem by dialing down the aggressiveness of my brake controller but to no avail. I do not have any braking issues during regular driving...only when coming to a dead stop. Should I follow your suggestions in diagnosing my problem? Regards, Jim

[Glenn Baglo]

What brake controller are you using?

If a Prodigy P2, the instruction pamphlet indicates to have "Boost" off for a trailer as light as Escape 19.

[jim hol]

Originally Posted by Glenn Baglo

What brake controller are you using?

If a Prodigy P2, the instruction pamphlet indicates to have "Boost" off for a trailer as light as Escape 19.

I'm using a CURT Discovery brake controller.

[Glenn Baglo]

No idea then unless the unit has a similar boost setting.
The behavior you describe is what I encountered when boost accidentally got turned on in my unit.

[gordon2]

Originally Posted by jim hol

I'm using a CURT Discovery brake controller.

I thought that time-delay brake controllers died out with the dinosaurs

But to be serious, even with my modern proportional brake controller it does seem to "stick" a little just before I come to a complete stop. It does not lock up the wheels but its pretty close to doing so.

[Pete Drewcock]

On my Oxygen, the grease seals were leaking due to welding debris on the shafts. The grease had gotten into everything. There was no stopping power at all. I cleaned up the shafts, repacked the bearings, replaced the seals, washed out the drums and shoes, and all good now.
It still means you have to get in there and look. Good luck!

[Raspy]

If you find grease on the shoes, it's best to replace them. Grease that remains, even after a solvent wash, can eventually make the brakes start to grab. Later, if you find one side trying to stop harder than the other, or pulling to one side, that is probably the problem.

[Pete Drewcock]

Originally Posted by Raspy

If you find grease on the shoes, it's best to replace them. Grease that remains, even after a solvent wash, can eventually make the brakes start to grab. Later, if you find one side trying to stop harder than the other, or pulling to one side, that is probably the problem.

Thanks! That's exactly what happened. I thought it was a lousy controller. I will replace the shoes.
👍

[Raspy]

Originally Posted by Pete Drewcock

Thanks! That's exactly what happened. I thought it was a lousy controller. I will replace the shoes.
👍