Adding brakes

[veebs]

Hi all,

I have a little ripper of a camper trailer, very strong, simple offroad suspension (leaf spring, attached at both ends) with a 45mm square axle running to 31" tyres. It has a few basics on it like a water tank, simple battery, etc.

I'm keen to add to this, by way of more water capacity, bike rack holder, extra battery, nicer kitchen unit, etc etc, but as it is unbraked, i'm limited to 750kg gross. I have no doubt that the D4 can handle more weight that this unbraked, but rules is rules, and I'm not interested in getting booked, or having potential insurance claims denied.

So, I'm looking to adding brakes, likely electric as the car already has a brake controller installed. Annoyingly, there aren't any mounting plates installed on the axles.

Time for my question - is retrofitting brakes something that is commonly done to trailers, and does anyone know of anyone doing that in/around Perth WA? I've read a bit about this online, but it all seems to be for DIYers - and messing with brakes is definitely not something i want to DIY! The original manufacturer is no longer in business, or I would have asked them to help.

Assuming it is all feasible and not cost prohibitive, who decides the trailer's new maximum weight? I'm assuming it is a calculation based on the suspension/axle capacity?

I'm not looking to get 3.5t into this thing, but a legal ability to load up to say, 1250kg or so would give me a bit more headroom...

135018

[Tombie]

Yes, you can get a kit with the plates to weld on for the brakes.

Option B is buy an axle with all the trimmings, their pretty cost competitive.

[weeds]

Complete Replacement axle v retrofitting.....probably would be much in it.

I’d go a new axle assembly.

[101RRS]

I put brakes on my 8x5 box trailer - because I was only going to be carrying a bit more that the max - maybe all up 1t I just went with override brakes but not a lot different as far as the mod is concerned. I had to get a new axle with the ends already welded on - they are cheap on ebay from trailer places. I only went up one size in capacity but obviously you need to get the right capacity.

Obviously I went with trailer hubs/brakes and coupling for override but same basic process for electric. There are complete kits available.

In theory my old springs and wheel bearings were good enough for the upgrade so did not change them however after carrying the load a few times wheel travel was not a lot and while bearings didn't get hot I suspect I will should also upgrade them as well.

Still running my old tyres - again well within the load range but I will put some offroad LT tyres on.

I dont recall costs but remember it was not expensive (eg $85 for the axle).

Garry

[roverrescue]

Load capacity (ATM) is the lessor of;
Axle rating
Spring rating
Drawbar rating as per ADR guidelines
Rim rating
Tyre load rating

If you are currently running 31s on a 45mm axle with eye to eye leaves and the trailer is ripper strong .... the axle (bearings) rating will be your limiter.
New axle with new hubs that much existing wheels and voila

If you went to a reputable trailer joint that makes trailers I’m sure they would help you with a new braked axle as well as supplying a new VIN with their recommended ATM that fits the new axle and your frame....

Likely the easiest thing will be to register it as a new trailer with a new VIN with upgraded ATM

In Qld there is a price break at 1250kg ATM ... worth considering rego costs

Steve

[veebs]

Brilliant - thanks all for the advice.

The ebay stuff looks interesting, though I will probably still end up going down the 'pay someone to do it' path - hopefully means it's less likely to die in the middle of nowhere because I did something wrong.

One thing i'd love to make sure i get right (or as right as I can) is to get it tracking the same as the D4. Could I trouble you for a quick maths/logic check?

D4 rear track width is 1612mm (using stock 19" wheels). The front is slightly less, but i'll use the rear, as that was the last track made before the trailer.

If the trailer wheels have a positive offset of say, 45mm, then my target hub face to hub face distance is 1612mm + (2 x 45mm) = 1702mm? or near-as-makes-no-difference to 67"?

Sound right?