Caravan brake backing plate mounting help ...

Joe,

I'm no 'van mechanic, but the brake shoes would need to "engage" with the brake drum, at least 4-6mm in from the edge you mentioned.

How would it be if you measured from inner edge of brake shoe, to the backing plate, and take 4-6mm off that distance? Also the folded edge on the backing plate is suppose to "guard" the edge of the brake drum, to stop dust/mud, from getting into the brake assembly.

Hope I've made that clear??? As mud he says LOL.

Just OT, we used to get morning glory's when we lived at Planet Downs, back in '86-'87. Magic sight, eh!

Bob.

I would be inclined to assemble the hubs with the mounting plates bolted the backing plates loose on the axle. Then with some suitable packing pieces, clamp the backing plates to the drums. Then you would be able to carefully weld the mounting plates to the axle.

I've just done this a few weeks ago and am working through the teething problems.

Today I got one trailer brake to lock up, so am pleased I'm getting somewhere. And yes folks, I will adjust the controller so I don't leave rubber all over the road.

I mounted 10" Al-ko electric trailer brakes with Landcruiser hubs onto my trailer as an upgrade. To control them, I installed a Techonsie brake controller a few months back.

I bought my brakes as a set from a reputable trailer parts place in Perth. He said to place a washer in between the backing plate and the mounting plate, do it all up tight onto the backing plate, then dry mount the hubs and tighten up the bearing nut.

I did this and then tacked the backing plate, dismantled it all and welded it on firmly.

On final assembly, I have what I would think is too large a gap in between the brake drum and the backing plate. There is enough room in there for small rocks and stuff to get caught I imagine.

One option I have considered is siliconing a strip of 25mm wide rubber strapping around the backing plate to create a loose seal.
The other option is to pull it all apart again and pack out the backing plate further away from the mounting plate.

But there are other considerations too.
Once I pull the brake drums off, I will be checking where the pads have been rubbing.
Second, I will also check on the placement of the magnet on it's mounting shaft.
I have off road magnets that are hideously more expensive than standard, so want to make sure they are mounted correctly.
Third, is that I have read that all adjustments should be done after 100km of city driving. I can vouch for this as my brakes are improving each time I use them.

From my experience, don't expect them to be fantastic immediately. Not sure why this would be the case, but it seems to be.

Wiring.
Each magnet only draws 3A (times 2 = 6A), but given the distances involved voltage drop is an important consideration - as it any dickyness in the trailer plug connection.
Make sure the earth wire is the same beefy size as the power wire. Not only on the trailer, but on the vehicle side as well.

It was easy enough to run a length of heavy cable back to the trailer plug, but so far I have left the earth wire as standard - quite thin. It is likely to be below par and another job is to replace it with heavier cable too.

I have figured that when voltage is applied to the magnet, it has a degree of magnetism dependent on that voltage. The magnet slides along it's mounting bracket and grips onto the inside of the brake hub on the vertical plane. This is a wearing point, hence worthwhile checking that backing plate to mounting plate distance.
As the magnet grips the rotating brake drum, it tries to rotate with the drums and pulls a lever. This lever actuates a cam, which pushes the brake shoes onto the brake drum.

If feasible, it would be a good idea to remove the axle completely and do all of this mounting away from the vehicle. Welding that backing plate on is not that easy, and needs a lot of paint to cover the results in my case. I suspect it is not under all that much strain really, but it's always nice to have a neat strong long weld.

I hope this is a bit useful, if nothing more than reassuring you that yes, getting the minimal distance between the drum and backing plate is probably a good idea - or so it seems!

Tim

Oh, and then there is the pad adjustment. That's another job......