Trailer Brake Trouble

Nissan11

Nissan11

Well-Known Member
Joined
Nov 29, 2005
Location
Marston, NC
I have a 1999 20ft dual axle Pace enclosed trailer. It has square 3500lb axles and 10" electric brakes. I have a tekonsha P3 controller. When I bought the trailer the brakes did not work great. In the highest boost setting and highest power setting the brakes would barely slow the truck down at idle on flat ground. Yesterday I bought 4 brake assemblies already on backing plates. I put them on, adjusted them through the hole in the back on the backing plate and they are doing the same thing. I have been taking voltage readings from the controller back. On the trailer side of the plug I have 11.7 volts with the controller lever taped all the way open. That is using the ground wire not the trailer frame. With the controller lever taped open I can hear a loud hum coming from each wheel which I assume is a good indicator that each brake is getting full power. If I have new brakes (did not replace drums) and power going to the wheels then why are my brakes not working?
 
@Nissan11

I would first off check the ground to the brakes. Trailer mfgrs are bad about using crimp splices on the wires.

Otherwise, new brakes require burnishing/breaking in. Brakes I just bought for my trailer say something (don't remember exactly, will have to re-read the instructions) like 50-75 applications of the trailer brakes, slowing from 50-25mph, with a 2 minute interval between braking (cooling intervals). So they expect you to drive around for a couple of hours hitting the brakes every mile or two.

Did you measure the drums to be sure they are still in spec?
 
kaiser715 said:
@Nissan11

I would first off check the ground to the brakes. Trailer mfgrs are bad about using crimp splices on the wires.

Otherwise, new brakes require burnishing/breaking in. Brakes I just bought for my trailer say something (don't remember exactly, will have to re-read the instructions) like 50-75 applications of the trailer brakes, slowing from 50-25mph, with a 2 minute interval between braking (cooling intervals). So they expect you to drive around for a couple of hours hitting the brakes every mile or two.

Did you measure the drums to be sure they are still in spec?
Click to expand...
I did not measure the drums. Do you know what the tolerance is?
The ground is a good idea. I never got a great resistance reading from the ground pin on plug (truck side) to the truck frame. I could only get a reading at the 200k setting and it read '50'. I figure it was good enough since all the lights on the trailer work. Is the ground wire coming from the plug supposed to ground to the trailer frame somewhere?
 
I just pulled all the brakes and wiring off my flatbed. Ground wire attached to the trailer with a ring terminal on one of the breakaway battery box bolts. It hooked to the harness ground wire with a clip on splice. Both connection points were corroded or rusted.
 
kaiser715 said:
I just pulled all the brakes and wiring off my flatbed. Ground wire attached to the trailer with a ring terminal on one of the breakaway battery box bolts. It hooked to the harness ground wire with a clip on splice. Both connection points were corroded or rusted.
Click to expand...
So the ground wire feeding the brakes should be grounded to the trailer frame somewhere? If it isn't, does it need to be?
 
Are these the connectors you are referring to?
20210314_152408.jpg
 
(In the computer business, I have had people get offended when I asked a really stupid question, like "Is the printer turned on?"....but I was on the right track too often to not ask....)

You said you replaced from the backing plates out. You did put the lefts on the left and the rights on the right, correct?
 
kaiser715 said:
(In the computer business, I have had people get offended when I asked a really stupid question, like "Is the printer turned on?"....but I was on the right track too often to not ask....)

You said you replaced from the backing plates out. You did put the lefts on the left and the rights on the right, correct?
Click to expand...
Yes. The assemblies were labeled. Big shoe goes to the rear.
 
Nissan11 said:
So the ground wire feeding the brakes should be grounded to the trailer frame somewhere? If it isn't, does it need to be?
Click to expand...

It isnt a bad idea to run a ground wire to the trailer frame, but it isnt required. If all of the brakes and lights run their ground back to the ground pin in the plug, that is best.
 
I ran dedicated grounds (10ga for brakes & 14ga for lights??... 100% LEDs, tinned marine wire and either crimped + heatshrink *OR* terminal strips + dielectric grease *ALL* inside PVC conduit + sealed pulled boxes for all connections) from the plugs terminal strip and to the frame when I rewired 5 years ago. After 5 years, I hitched it up last week and magically, EVERYTHING works *and* the 5 y/o deep cycle manages to stay charged (zero parasitic drain) while unhooked...
 
Update- I took the trailer to VA. The longer the trip went on the better the brakes felt. When I got home, at 20 mph on gravel I slid the controller lever over and the driver side front wheel locked up. When I got home both driver side wheels were hotter than they should have been and the passenger side was cool. I think the brakes are starting to work and plan to adjust them again this weekend. I can only figure that the shoes needed a break in period.
 
Last edited:
Nissan11 said:
Update- I took the trailer to VA. The longer the trip went on the better the brakes felt. When I got home, at 20 mph on gravel I slid the controller lever over and the driver side front wheel locked up. When I got home both driver side wheels were hotter than they should have been and the passenger side was cool. I think the brakes are starting to work and plan to adjust them again this weekend. I can only figure that the shoes needed a break in period.
Click to expand...
I see the same thing from my trailer after sitting a few weeks... barely had brakes Sat AM and got increasingly better after 3 roundtrips

My guesstimation used to be that the inside of the hitch carrying ground (via ball) took a few miles to wear the rust off for the brakes to begin working better.
BUT, with a dedicated wired ground, that should be negated... 🤔
New pontification, the magnets have to overcome a fresh layer of rust/grime to work and that's why they slowly come in?
 
Caver Dave said:
I see the same thing from my trailer after sitting a few weeks... barely had brakes Sat AM and got increasingly better after 3 roundtrips

My guesstimation used to be that the inside of the hitch carrying ground (via ball) took a few miles to wear the rust off for the brakes to begin working better.
BUT, with a dedicated wired ground, that should be negated... 🤔
New pontification, the magnets have to overcome a fresh layer of rust/grime to work and that's why they slowly come in?
Click to expand...

It is possible that the drum brakes make a layer of rust like a rotor I suppose, and since trailers sit so long they might take longer to clean themselves.
On my hyundai parking brakes (drum brake inside disk brake rotor) I replaced the shoes and hardware about 4 months ago. I noticed the brake woukd not keep the car from rolling when parked or slow it down much when driving down my driveway. I made it a point several times when on the highway to pull the lever to try to heat them up a little and they have slowly started to work better.
I didn't think the hyundai brakes had a similarity to the trailer brakes but both have new shoes and old drums. I still don't know what is going on unless the braking surface is dirty, the brakes need to be warm to work or new shoes need to be broken in.
 
On the hyundai they probably have typical auto adjusters.
Old school lost art, when replacing drum brakes and setting the adjuster they adjust only when backing up. So old timers would change brake shoes and then back up and stop 10-12 times untilt he shoes adjust.

Im not sure that trailer brakess have the same feature
 
Ron said:
On the hyundai they probably have typical auto adjusters.
Old school lost art, when replacing drum brakes and setting the adjuster they adjust only when backing up. So old timers would change brake shoes and then back up and stop 10-12 times untilt he shoes adjust.

Im not sure that trailer brakess have the same feature
Click to expand...

If they were out of adjustment I'd be able to pull the parking brake lever up all the way right? It has a way shorter range of motion that it had before I changed them, and they were working fine before I changed them, just worn out. I can only pull the lever up about 1/2 way and it is tight.
 
would depend on the system and how the cable is set up (ratchet vs direct pull) but
 
Back
Top