32 foot TT, about 7000 pounds plus our gear and stuff:I've noticed the brakes are underperforming substantially. Got the gain on the Prodigy turned all the way up, when I grab the lever and throw max voltage at the brakes, all it does is slow the thing down a little. I'd say maybe 20 percent efficiency at best.Not good enough, time to open it up.I've been wrenching my own vehicles since I was a teenager, I rebuild engines, trannies and every other aspect of cars and pickups, therefore I know what I'm doing with mechanical things.I've been doing brake jobs all my driving life.However, I have never had trailer brakes apart.I'm wondering, do most trailers have a similar adjustment technique as the old drum brakes on the old 60s and 70s cars? Where you pull off the little rubber cap on the backing plate and get in there with a brake tool or bent screwdriver?Weak brakes, could they just be suffering from bad need of adjusting?Are they self adjusting like the old cars or do we have to get after them once in a while?Just thought of this now, but suppose I should get under there, probe the wires and make sure I have voltage at the hubs....Should be able to lock the wheels up with full on braking. Not so here...Tips and tricks for getting my brakes in order? Best method to check each wheel?Guess I should pull the drums and have a peek anyways.Long trip coming up soon, gotta take care of this before departure. TT is 12 years old, maybe it needs shoes.

It is very likely that they do need adjustment. They significantly loose mechanical advantage between the actuation magnet and the shoes when they have too much clearance. They adjust exactly like you say. I recommend replacing the bearing seals while you are in there. It's pretty easy work but quite messy.

Trailer brakes are actuated by magnets dragging on the inside of the brake drum. The amount of force can be measured with an ampmeter. The draw for fully applied brakes is a little over 3 amps per brake. You can add an ampmeter in series with the wire from the controller on your dash to the brakes on the trailer. There should be a leveler on the controller that allows you to manually apply the brakes.Some are self adjusting and many are not. They can be adjusted with a standard spoon from the days when brake drums were used. You'd need to pull the drum to see what you have. Take measurements of the width of the shoes and the diameter of the drums as well as checking to see if they're self adjusting while you're looking. The brake shoes and magnets do wear out and need replacing. The easiest way to do that is to replace the whole backing plate. That gives you new shoes, magnets and all new hardware.There's lots of information here as well as decent prices:https://www.easternmarine.com/trailer-brakeshttps://www.easternmarine.com/electric-trailer-brake-assemblies

Bob,I've been to your movie.I replaced the backing plate, adjusted the brakes, replaced the magnets, replaced the controller... Still no real breakingLong story short. Check the wear on the inside of your drums. My prior controller must have been sending some power to the magnets, they dragged and wore down all four drums inside face where the studs are pressed into the drum. the magnets were shot and when I replaced them, they wore into the shape of the drum eventually (about 1000 miles worth of driving).The surfaces worn down concave (convex? I never remember which is which) to the point where the brakes didn't work enough to really stop the trailer.Ultimately, I replaced the axles because it was about the same price as getting new drums and backing plates, and magnets - and they had a higher weight limit (6,000 versus 4,400 each axle).PM me if you've got questions.josh

Bob,Trailer brakes easier then buttered furnace duct.Yes trailer drum brakes just like days of old except electric/magnet actuating shoes vs hydraulic slave cylinder12 yrs old.......it time for some new shoes and internalsBuy 2 right side and 2 left side backing plate assembliesBack the adjuster off...remove drumsDisconnect 2 wires to magnet..4 bolts and old backing plates come offNew inner/outer bearings/sealsAfternoon job...one side at a time/one wheel at a time

Yes you should certainly adjust the brakes at 12 years. Actually 12 months or 12,000 miles would be OK also. OK to repack the bearings at this point too.Yes they adjust same as all other drum brakes.A few are forward self adjusting but I assume yours are not. When you pull them apart you will see a familiar cable and adjuster if you have this option.Some lock up and others do not but you should get very significant braking force when full power is applied manually. Although I found after sitting in storage the initial braking was a bit less until you make 5 or 10 stops to get them worked in a bit.Best electrical check is a clamp-on DC ammeter reading. At full power you should see about 3 amps through each coil. More and you have a short, less and you have a bad connection.Shoes last a long time with mostly highway miles. The material seems thinner than a vehicle so unless it is very thin I would keep running them.Keep us updated with what you find. Post a picture if something does not look right.

Trailer brakes weak, a few questions: | Good Sam Community

BobsYourUncle
Nomad
Jul 26, 2019
Old-Biscuit wrote:
Bob,
Trailer brakes easier then buttered furnace duct.

LOL!!
I'm never gonna live that one down! :B :B

Some of you guys have a good memory!
BobsYourUncle
Nomad
Jul 26, 2019
ajriding wrote:

How long did / have you driven your trailer with unsatisfactory brakes?

Last summer going through the Canadian Rockies, I noticed they were not as efficient as they should be. They worked, but could have been better.

Took it out last weekend for the first time this year to bring it home to dewinterize. Noticed it was worse, much worse...

Taking care of it before an upcoming trip
DFord
Explorer
Jul 26, 2019
3 AMPS PER MAGNET should be able to lock the drum. That would be the maximum current draw per brake. Usually much less than that but if you're magnets are drawing anywhere near that much power and the brakes aren't working correctly, it's not a wiring issue. It would be time to pull a drum and see what's going on inside.
wopachop
Explorer
Jul 26, 2019
Wait a second. This came up before with the emergency brake system.

If you remove your batteries from a trailer will the brakes work properly?
BobsYourUncle
Nomad
Jul 26, 2019
On another note, how do I ID the brakes for replacement parts aside from a visual comparison after pulling it apart? In case I need to buy shoes, drums, magnets or whatever.

Gotta be something stamped, tagged or ? To ID them
DFord
Explorer
Jul 26, 2019
Dexter Axle makes most of them. Look all around the Eastern Marine website. They have all sorts of educational material besides the parts.

Also peruse the Dexter Axle website: https://www.dexteraxle.com/ They have lots of support information available.

Lots of links to instruction sheets on this page:
https://www.dexteraxle.com/products/brakes-brake-accessories

Etrailer's website is also very helpful:
https://www.etrailer.com/question-143453.html
stevemorris
Explorer
Jul 26, 2019
ajriding wrote:
3 amps or 3 volts? previous poster said this… Should not matter unless you suspect issue with wiring or controller. Brakes work off a 6 volt system, not 12. The max output for the controller is 6 volts. That should be 6 volts per brake, not 3 (amps get divided, but not volts here). Usually anything over 2 will operate the brake magnet then from there to 6 will increase the magnetism and increase the braking power.

I recently let trailer sit for a couple of months then the brakes were very, very weak at first. I had the controller set to max and still was not great breaking. 2 hrs drive and I could gradually lower the controller setting and the drive back I was back to normal with the controller set very low to get the power out of the brakes I wanted.
Maybe the drums rusted over and it took that long to wear it off and evacuate the debris from the inside of the drum? I don't know.

The trailer should at least be able to stop its own weight.

How long did / have you driven your trailer with unsatisfactory brakes?

Brake pads should be able to sit for 12 years and still work, though the steel parts might see some rust and need exercising or brake grease to move easily.

Easier to lock up one wheel on a tandem than on a single axle trailer. Easier still on gravel.
They need to be adjusted, as stated above, as the brake pads wear out and to keep all wheels performing at the same level. Typical drum brake adjustment rules apply. See any of the many instructional videos or post on topic.

6 volts? seriously? not on my trailer they don't nor any other ive had

brake magnets are in parallel and all see 12V at full power and 3 amps each(depending on size) for a total of 12 amps on a tandem trailer

the biggest issue with the electrical system for these brakes is voltage drop due to the high current draw. this is usually because of insufficient wire size and or bad connections.

all of the wire used has to be big enough, all the way from the tow vehicle battery to the brake controller, to the 7 pin connector and around the trailer. that's a lot of wire!
BobsYourUncle
Nomad
Jul 26, 2019
DFord,
Thanks, that's helpful.
Groover
Explorer II
Jul 26, 2019
wopachop wrote:
Wait a second. This came up before with the emergency brake system.

If you remove your batteries from a trailer will the brakes work properly?

For normal stops, yes. The power comes from the tow vehicle. Batteries on the trailer supply power for breakaway situations. Important if needed but hopefully you will never need that. And it probably is a different battery from the one that runs the camper. You should pull the breakaway cable now and then to be sure that the emergency breaking works.
Groover
Explorer II
Jul 26, 2019
BobsYourUncle wrote:
ajriding wrote:

How long did / have you driven your trailer with unsatisfactory brakes?

Last summer going through the Canadian Rockies, I noticed they were not as efficient as they should be. They worked, but could have been better.

Took it out last weekend for the first time this year to bring it home to dewinterize. Noticed it was worse, much worse...

Taking care of it before an upcoming trip

If I let my trailer sit very long at all I have to do several stops using just the trailer brakes to get them working effectively again. Even then they don't ramp up well. Great for normal stops but not for rapid stops. And I keep the trailer out of the weather so that shouldn't be a factor.

If you do major work on the brakes keep in mind that you may need to burnish in the new parts to get effective braking. This can take a while.

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