Thanks for the feedback guys.

I am running 4mm wire back to the trailer plug and have tested the circuits and plenty of current getting through.

All the cabling under the caravan is wrapperd up pretty good so I'm looking to rerun fresh wiring through for the brakes.

Just have one question though.... From researching how to do this it looks like I have to earth to the van and back to the trailer plug. Is this right???

Cheers

Hi 4x4xfar, and welcome to the forum. As you can see there is a wealth of info from the many helpful members here.
You may have stumbled on the actual cause of the problem - the earth. Yes you are correct and the earth from the van (chassis) needs to be wired back to the plug that connects to the tug. I recently had a problem of the brakes not working and when I had a look at the wiring everything seemed to be in order until I checked the earth connection. It had worked loose over the years but when I cleaned it up and tightened it again,- voila - I had brakes again. Yes intermittant faults can be so hard to find. Hope this sorts it out.
Cheers
Roger

Well some time has passed.... been an interesting few weeks here in Brisbane.... much like most of Qld actually...

I got the voltmeter out and there was a short (aka voltage drop) between the caravan plug and the brake magnets and seeing as the wiring is so well protected and runs inside the rails decided to run fresh 4mm wiring for the brakes as well as new magnets and voila I have 1 functioning brake.

With the brake controller manually full on I have 12v to errant brake and it is energised however it fails to engage most of the time and when it does is weak.
When I spin the wheel backwards the brake engages more but not a lock up. The other wheel is locked. I though maybe an ampage problem so disconnected the good brake and no change to the problem.

Doing some research I see other posts around the various wwws about grinding the drum but can't seem to fathom out is it the brake shoe surface they are talking about or the surface the magnet enagages with.

If this surface isn't polished smooth, ie some grooving, would this explain the poor braking???

Cheers.....

Hi 4x4xfar,
Some info that may help with your fault finding:
Each brake electromagnet should be 3.5ohms
One pair should read 1.75ohms
Some lesser meters have trouble reading resistance that low or accurately.

The electromagnet should have enough power with a voltage of about 10.5 to 11volts, that is the voltage at the magnet not at the van plug.

Usually the brake shoe surface on the drum is the only surface that will need machining if any.
The vertical magnet surface can be a little rough and still work, not many machine shops will do the vertical surface anyway. It would also depend on how close the back of the wheel studs are from coming through.

Does your brakes have round magnets or oval magnets as the round ones do ware more uneven and can do more damage to the vertical surface of the drum assembly. Also if they are the round ones your system is a bit old as most use the oval magnets these days.

You mentioned that you have 12V at the brakes, that is pretty good almost sounds to good, it would be worth checking you have a circuit through that brake solenoid even though it is new.

The brake that is not engaging much sounds like the magnet has a problem or the magnet is not reaching the vertical surface to hold on or there is some internal mechanical problem.

JR

Hi JR.... Thanks for the info.

Sorry should be more specific... I have 11.4v at the join of the new alko off-road magnets.

So just to clarify.... as long as the drum surface that the magnet rides on is clean, it doesn't matter that there is some grooving??

Did notice whilst I was poking around the brake mechanism that the actuator arm did seem a bit stiff to slide... could this also not be helping the situation???

Do these actuators wear or is a matter of smotthing the surfaces???

Cheers......

Hi 4x4xfar,
11.4V sounds good, the surface that the magnet runs on is best if it is not marked but in time they usually sustain some scratching and grooves, I guess there is probably a cut off point that they need to be machined or replaced.

Yes if the actuator arm is stiff it needs to be able to move free as the magnet moves that arm which in turn pushes the brake shoes apart. The arm swings on a bush bearing that may need attention and lubricating. Also check the brake shoes are not glazed and naturally adjusted up OK usually click up until the wheel cannot turn then come back about 8 to 10 clicks. Don’t get caught like so many do and come back only 3 or 4 clicks, you need more.

When you say does these actuators wear are you talking about the electromagnet if so they do wear and usually have special holes at a set depth in the contact surface and when these holes are almost gone then it is time to replace magnets.

The rate of wear will depend on many things like how heavy you have your Prodigy set, how many K’s you have travelled and if you travel gravel roads and sand, sand will really make the wear rate go up.

JR