Thread: Towing braked trailers

Originally Posted by Savage1

You need a brake controller, get an inertia one. Electric brakes are pretty much standard on modern caravans.

The cheap dial ones that live on the drawbar are crap, and borderline dangerous. I had one of these and to have it setup for driving at 50km/h+ meant that it would lock up every time I touched the brakes doing under 20km/h. Some Jaycos come with these.

I installed a Tenkosha P3 which is awesome but would probably put in an elecbrakes drawbar setup if doing again, just for simplicity and not having to modify the tow vehicle. It is so much less stress with a decent brake controller.

fully agree.
heres the link.

https://www.elecbrakes.com/

Originally Posted by No.3

....others have an inertia sensor to tell how hard you are trying to stop and then matched it with the trailer brakes so it doesn't lock everything up on application...
..

I had a local SxS dealer bring up one of his toys so I could try it out on the block. He was cursing the brake system a guy had put on his brand new flat deck trailer- barely touching the ute's brakes would have the trailer lock up and the controller couldn't be adjusted to stop it. He was beyond pissed off..

I still think for simplicity that the good old hydraulic over rider system is hard to beat.

Easily maintained and you can turn it off if you need to.

Originally Posted by tac a1

I still think for simplicity that the good old hydraulic over rider system is hard to beat.

Easily maintained and you can turn it off if you need to.

I think hydraulic override couplings are only allowed up to 2500kg, I think, could well be wrong.

Originally Posted by Savage1

I think hydraulic override couplings are only allowed up to 2500kg, I think, could well be wrong.

Correct, 2500kg max.
There is a mechanical override drum brake system available rated to 3500kg. Same as on Ifor Willams trailers & the likes. Meets EU regs to 3500kg so applicable here in NZ too.

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Originally Posted by Mathias

Correct, 2500kg max.
There is a mechanical override drum brake system available rated to 3500kg. Same as on Ifor Willams trailers & the likes. Meets EU regs to 3500kg so applicable here in NZ too.

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Which is crazy. Disk brakes are so more effective than drums. They dispate heat so much better. Drums bloody overheat. Useless bloody things

Part of the reason for this is that the 2500Kg master cylinder is only rated to operate one braked axle or one set of disc's. A 3500Kg trailer is required to have both axles braked and the override coupling can't push that much fluid to operate all four calipers without making the WoF man think that the brakes are spongy and need bleeding... Ask me how I know this haha (oldmate thought it would be a 2 is good, 4 must be better in terms of numbers of calipers on his braked tandem boat trailer). It did stop well, I'll give it that but we could not get it past WoF once the little Indian inspector killed it for spongy brakes. The brakes passed in every other respect, good stopping power etc etc it just was too much fluid required to push out all four pistons compared to the available volume in the master cylinder. We actually looked at custom fitting a double master cylinder setup onto the coupling, but that wasn't allowed and also custom building a larger master cylinder but again not a goer. Ended up either needing to drop back to two calipers or only one braked axle or what we did in the end and fitting a US made electric/hydraulic actuator with wireless controller.

This discussion got me thinking,

Why do caravans (often weighing less than 3 tons) need an electric brake while other 3.5T plant trailers don't have one?
My 3.5T Brian James trailer doesn't have any electric brakes and no safety chain (I can understand this part).
The trailer comes with 7-pin plug, a carabiner clip for the mechanical over-ride brake and that's it.

Am I missing something here or does a 3.5T plant trailer need an electric brake too?

Originally Posted by Snap 4T

This discussion got me thinking,

Why do caravans (often weighing less than 3 tons) need an electric brake while other 3.5T plant trailers don't have one?
My 3.5T Brian James trailer doesn't have any electric brakes and no safety chain (I can understand this part).
The trailer comes with 7-pin plug, a carabiner clip for the mechanical over-ride brake and that's it.

Am I missing something here or does a 3.5T plant trailer need an electric brake too?

Nup, your BJ trailer has brakes that I was referring to in an earlier post and its a whole different set up to electric. Its rated to 3.5T on mechanical 4 wheel braked drums, ECU approved.
Electric drum brakes are electromagnetic, which use varying voltage (0-12v) to apply the brake force via a magnet that tries to attach itself to a rotating drum face and cam on the brake shoes.

Originally Posted by No.3

Part of the reason for this is that the 2500Kg master cylinder is only rated to operate one braked axle or one set of disc's. A 3500Kg trailer is required to have both axles braked and the override coupling can't push that much fluid to operate all four calipers without making the WoF man think that the brakes are spongy and need bleeding... Ask me how I know this haha (oldmate thought it would be a 2 is good, 4 must be better in terms of numbers of calipers on his braked tandem boat trailer). It did stop well, I'll give it that but we could not get it past WoF once the little Indian inspector killed it for spongy brakes. The brakes passed in every other respect, good stopping power etc etc it just was too much fluid required to push out all four pistons compared to the available volume in the master cylinder. We actually looked at custom fitting a double master cylinder setup onto the coupling, but that wasn't allowed and also custom building a larger master cylinder but again not a goer. Ended up either needing to drop back to two calipers or only one braked axle or what we did in the end and fitting a US made electric/hydraulic actuator with wireless controller.

Standard override has a 3/4" master cylinder, you need to fit a 7/8" mc to drive 4 calipers effectively. Though its bloody hard to bleed every last bit air to get rid of a bit of sponge. Still only rated to 2500kg on override, with 4 wheel braking.

Originally Posted by Mathias

Nup, your BJ trailer has brakes that I was referring to in an earlier post and its a whole different set up to electric. Its rated to 3.5T on mechanical 4 wheel braked drums, ECU approved.
Electric drum brakes are electromagnetic, which use varying voltage (0-12v) to apply the brake force via a magnet that tries to attach itself to a rotating drum face and cam on the brake shoes.

Having done a lot of heavy towing with Brian James trailers I can say this is the standard all trailers should aspire to in the brake department.
Same with ifor horsefloats.

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Originally Posted by Mathias

Standard override has a 3/4" master cylinder, you need to fit a 7/8" mc to drive 4 calipers effectively. Though its bloody hard to bleed every last bit air to get rid of a bit of sponge. Still only rated to 2500kg on override, with 4 wheel braking.

This. Ive done plenty of trailers with dual braked axles. You must have the bigger master cylinder.

Originally Posted by BRADS

Having done a lot of heavy towing with Brian James trailers I can say this is the standard all trailers should aspire to in the brake department.
Same with ifor horsefloats.

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Yeah, they use the German Alko mechanical drum. I implemented the sale of these as braking kits into the NZ market with my previous job. I tested all forms of braking on a 3.5T platform trailer that was our testbed and these performed extremely well. Agree with your comment.

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Originally Posted by Mathias

Standard override has a 3/4" master cylinder, you need to fit a 7/8" mc to drive 4 calipers effectively. Though its bloody hard to bleed every last bit air to get rid of a bit of sponge. Still only rated to 2500kg on override, with 4 wheel braking.

Yes, but the fly in the ointment is that overriding all the above is that you have to be able to stop in 7m at 30km/hr.

Originally Posted by Mathias

Standard override has a 3/4" master cylinder, you need to fit a 7/8" mc to drive 4 calipers effectively. Though its bloody hard to bleed every last bit air to get rid of a bit of sponge. Still only rated to 2500kg on override, with 4 wheel braking.

No, was running 7/8 and still not good enough. I know what the recommendations are - don't know why it didn't work in this instance. Properly vacuum bled and fully backfilled system with the front of the trailer lifted into the sky and any air traps were straightened to release all air from the system - but it just couldn't move enough fluid without the piston in the master cylinder having to move to the amount that gave the inspectors the spongy feel. There was nothing 'wrong' with the system, no leaks, no air, no mechanical problem and it passed the test just fine in terms of braking effectiveness - it just literally didn't move enough fluid ina short enough distance to make the inspector happy with the operation of the master cylinder. Needed to go to a full 1" we reckoned to get it to the point of success which is a foreign product - but in the end of it to strengthen the trailer to the point of not killing duratorque axles every other year and fix a few other issues it basically went past the 2500Kg rating limit of the override coupling, so with all of those other issues in the mix it was a case of "lets use the ton" and fix everything including a electric/hydraulic actuator. Went from spongy to locked up in f-all and a WoF inspector that tried to fail it because he'd never seen one before and couldn't drive it (facepalm). Was good after that though.