Trailer brakes weak, a few questions:

[BobsYourUncle]

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.

[BobsYourUncle]

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

[BobsYourUncle]

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!

[ajriding]

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, according to one manufactures, but 12 on most.according to one manufactures, but 12 on most.… edit

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.

[DFord]

That's great if you live in the mountains.
When I first installed a new controller for my electric brakes and before adjusting it correctly, I had no problem in locking up the trailer brakes. I had to back off that original setting quite a bit before they worked correctly. I could easily feel the trailer brakes working when stopping. The main problem I had was sliding the tires till I finished adjusting them. The ampmeter helped a lot.

[Groover]

I have never been able to get electric brakes to work to my satisfaction. In fact, I just ordered a new trailer for my business with electric over hydraulic brakes for safety reasons. I am seriously afraid that the electric drums on my equipmenet trailer are going to kill me. I intended to wait until have a few thousand miles on the trailer to post this but since you brought it up here is what PJ trailers has to say about electric brakes:


"Electric Brakes vs Hydraulic Disc Brakes

The one advantage that electric brakes have over hydraulic disc brakes is the initial cost is lower and that is only true advantage. As most hot shot truckers will tell you, the hydraulic disc brakes are more expensive up front but are cheaper to maintain. Hydraulic disc brakes outperform electric brakes in stopping power, have less brake fade and better heat dissipation. If you live in area with hills or mountains, upgrading to hydraulic disc is even more important.

PJ Trailers on electric drum brakes

[BobsYourUncle]

Thanks for the input everyone.
🙂

[jfkmk]

As mentioned, working on trailer brakes is aa simple as it gets, especially for someone who works on cars. Repack the bearongs too.

[time2roll]

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.

[Old-Biscuit]

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 cylinder

12 yrs old.......it time for some new shoes and internals
Buy 2 right side and 2 left side backing plate assemblies
Back the adjuster off...remove drums
Disconnect 2 wires to magnet..4 bolts and old backing plates come off

New inner/outer bearings/seals

Afternoon job...one side at a time/one wheel at a time

[jodeb720]

Bob,

I've been to your movie.
I replaced the backing plate, adjusted the brakes, replaced the magnets, replaced the controller... Still no real breaking

Long 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

[DFord]

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-brakes

https://www.easternmarine.com/electric-trailer-brake-assemblies

[bartlettj]

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.