Thread: New boat trailer build

Yonnee

Dont laugh to loud mate, these axles are second hand and need sand blasting. I will then get them hot meatl sprayed which will make them last for years. I also noticed on one of the plates that the holes dot quite line up, Im wondering if I should just cut them off and weld new ones on? As for the electric brakes, will they work out more expensive than the normall breakaway system. I dont know much at all about brakes on trailers so its all a bit new to me.

Stu

Sorry...

From what I can see, the inner brackets were possibly for another set of rims. The little 9" alloy wheels you see on alot of boat trailers are too small to allow calipers and disc rotors to tuck inside the rims, so there's a different set of brakes for these that the rotor has a long snout which places the disc part of the rotor and caliper beside the wheel and tyre. My guess is that someone has put 14" wheels and tyres on with standard rotors, hence the second caliper bracket. They don't need to line up with each other as they are not used together.

It also looks like you have "Slimline" bearings too, which with non load sharing suspension, will give you a carrying capacity of 2400kg on those axles.

The electric system is a normal breakaway system, and probably the most cost effective. Until the Electric-over-Hydraulic system was developed, the only other way of running a breakaway system with hydraulic brakes on the trailer was to set the tow vehicle up with either a compressed air system, or a vaccum system, both of which require major additions to the tow vehicle and were in the vacinity of a couple of $K plus labour. The Electric/Hydraulic part for the trailer should be around $1500 and a controller in your car start at around $100 plus fitting for a good one. (Beware the controller brought out by a reputable towbar manufacturer, IT'S RUBBISH) I'm not going to name names here, just covering my 'backside'.

Originally Posted by stu

I dont know much at all about brakes on trailers so its all a bit new to me.

Mate, that's what I'm here for.

Yonnee.

Yonnee

Is the $1500 plus $100 all I need to spend on brakes or is there more to it than that? Im glade I dont have to cut those brakets off the axles that would could be a messy job. I have older ford alloy rims, will the rims fit over the calipers or do the rims sit away from the disc and calipers to some degre? The brakes, rims, axle set up is far more complex than building the trailer. I thought the trailer was going to be the hard part as it turns out, its the rolling stuff that is the headach.

Stu

The headache is getting all the clearances right.

The $1600.00 is the tow vehicle and breakaway side of it. You'll still require the brake kits themselves for each axle. And your rims should fit over the calipers, same as your car ones do. I say 'should', as some alloys are thicker than the normal steel rims and their offset can make them a tight fit, but you shouldn't have any problems.

Have you made the trailer to suit the axle mounts? And what mounts are on the axles? You only showed me a picture of the swing arms.

Y.

p.s.
If you look at it this way, spend the money now on the right gear for the trailer and it will last you alot longer, and do a better job than a cheaper alternative. You can scrimp, but yours, and others safety is at stake when it comes to braking nearly 4500kg of boat and tow vehicle.

Yonnee

Thanks mate, No way Im going to scrimp on the braking side of things, just needed to know what Im up for. I will have to post up another pic of the axle mounts. I have built the trailer to suite the axle mounts, they sit right in the middle of the mounts, 1445mm that way I can easly get the U bolts on with out any trouble what so ever. Is there any extra bits I need for this breakaway sytem that fits onto the breaks on the trailer or is it just the disks and calipers?. Buy the way is that $1600 from the company down in Vic, if so thats heaps cheaper than up here in QLD. I have had quotesw of over $2500 for the airtank type.

Stu

Well don't "quote" me on the price, I have a four year old price list, but give them a call, 03 9772 2333. They supply axles all over the place, and it shouldn't cost you more than $100 to freight it from Melb. to Sunny Coast.

For the record... You need;
1 x Electro/Hydraulic unit (H1600 for disc brakes)
I'm pretty sure the kit sold by Melbourne Trailers has the breakaway kit included. Even for those under 2000kg, it's still a good way to have "Electric" Disc brakes.

1 x Electric Brake Controller for tow vehicle. (Tekonsha, Kelsey or Dexter recommended)

2 x pair hydraulic calipers, disc rotors and bearing kits. (Here the spacing of the holes in the caliper mount brackets will determine whether you require PBR or Trigg calipers.)

4 x Flexible brake lines and enough bundy tube to plumb it all up.

And that's pretty much it.

It sound like you've got the mounting of the AL-KO's sorted, my only concern is if you're going to 'U'bolt them (best way for adjustability), you'll need to brace the 'C' channel along this point or you'll collapse your chassis rails by tightening the 'U'bolts.

Y.

Up here in QLD e need 4 calipers or one on every wheel for trailers over 2000kg. Will a standard caliper be ok or do i need a special type of caliper to fit the electric system. When you say electric disk brakes do you mean that literally or do the calipers hook up to normal hydrolic hose with fluid and then that goes up into some electric pump system? What is bundy tube? As for bracing the C channel I was going to use some 6mm plate the entire lenght of of where the U bolts will be situated.

Stu

Originally Posted by Stufart

Up here in QLD e need 4 calipers or one on every wheel for trailers over 2000kg.

As does the rest of Australia.

Originally Posted by Stu

Will a standard caliper be ok or do i need a special type of caliper to fit the electric system.

The standard caliper that bolts onto your existing mount will be fine.
There are two main options in the trailer industry. They run different bolt spacings and won't interchange.

Originally Posted by Stu

...do the calipers hook up to normal hydrolic hose with fluid and then that goes up into some electric pump system?

Got it in one! That's exactly what the Electro/Hydraulic system is. A system to control hydraulic brakes on the trailer with an electric controller in the tow vehicle. It also allows the hook up of a battery and switch as a breakaway system.

What is bundy tube?

Sorry... the tube the brake fluid runs in. Can be either steel or copper, although copper is not legal in some states.

Originally Posted by Stu

As for bracing the C channel I was going to use some 6mm plate the entire lenght of of where the U bolts will be situated.

Stu

Cool!

What suspension are you going to use? If leaf springs, make sure you can mount so you can shift up or down the length of the trailer in order to get a good tongue weight at the ball hitch but a weight that you can still move yourself when unhooking from the tow vehicle. Wayne

Wtrueman

I will be using Al-Ko axles, like or much the same as tor axles. Yonnee, Im now with it mate. By the way, how much weight should be on my tow ball? My boat trailer will weigh around the 2100kg mark maybe 2200kg. I have had heapes of differing opinions on this matter, some say 10% of total weight, others say so you can pick the trailer up at the tow point. I dont like the idea of being able to pick 2200kg boat and trailer up by myself, means there is stuff all weight on the tow ball, things could get bad out on the highway.

Stu

Yeah, the 10% figure is usually the one thrown around, but I beg to differ. 10% might be a good rule of thumb for most single axle caravans that weigh between 800kg and 1500kg, but these days with so much variety in trailers, most ideal towball weights need to be assessed on a case by case basis. One thing people don't take into account is the wind loading on a trailer at 110km/h. A tall trailer can seriously lose all its ball weight at that sort of speed (even though the stationary ball weight might be quite high), and the next thing you know the tail's wagging the dog and trying to drag you off the road. Suspension can also have an effect; load-sharing versus non load-sharing.
For yours, I'd be aiming for 120kg or so. But having said this, be careful of some cars towing capacities that limit ball weight maximum to this, even though their actual towing capacities may go close to 2200kg.

Ok, I have welded the drawbar on but haven’t yet welded the cross member on. This was a nightmare doing this on my own. The drawbar is 1800mm long by 150 by 50 by 5mm wall. This Is all I could get on the whole Sunshine Coast. I have one concern with the drawbar though, over the length of the trailer the drawbar is ¾ inch to one side. I have 1 meter of drawbar hanging out past the welded “A” frame section of the trailer. I’m really miffed because I hate things that are out more than 5mm. I’m going to put a couple of sash clamps on hr in side of the drawbar to see if I can pull it over a bit. I suspect that I can make the adjustment when I put the axles on though. The other Idea I hade was to place the coupling a bit further over than normal.

Stu

Attachment 72433

You could try this, if haven't welded the cross rail in at the back of the drawbar.
(I hope it's clear enough)

Yonnee

I ran two string lines along each main rail; I then measured from those points to the middle and then come to the disgraceful conclusion the drawbar is in fact 40mm to the left of the photo. I was going to cut the right hand section right off and then bend the left over a bit utilizing the cuts as you mentioned. Not Happy Jan.

Stu