Before doing any cable fitting, it is advisable that the trailer is fully prepared and painted or galvanised and at the bare minimum, has a primer coat applied.
From the front of the trailer, slide a semi-rigid section of mild steel "pull" wire down the drawbar until it comes out at the spring end. Tape the trailer 5 core cable (seven core if you are fitting electric brakes) to the end of the "pull" wire and pull from the spring hanger end until the cable comes through.
Gently pull the cable through until you have a good length that will reach along the length of the trailer and across the rear light channel. Allow another 300-400mm extra of cable to play with.
Allow another 600mm extra at the coupling end of the drawbar for wiring into your plug.
Drill through any cross members not already drilled to allow the cable to be threaded through. Thread the cable from the spring hanger end of the drawbar, through the conduits and cross members until you reach the position of your first light. Add on an extra 150mm of cable and cut.
Thread the left over cable through the conduits along the light channel to the second light.
Make sure that your number plate light is in the correct position and that the light will shine on the plate. Keep your lights as wide as possible in the light channel, but do not place lights directly behind the rod bracing.
Mark out your light position on the light channel and drill the mounting and cable holes as per your lights instructions or template
There are a couple of ways of joining the wire together behind the left hand light. Using a strip connector inside a sealed junction box is one of the best ways of keeping the join secure and weather tight and also gives the option of easily changing lights should they get damaged, etc.
Other options include soldering the wires together and sealing with insulation tape and a heat shrink tube or using crimp connectors and covering again with heat shrink tube. These options take less time to do than the first option, but will cause a bit of a headache when maintenance needs to be done at a later date.
If you go down the junction box route, secure the box to the chassis rail directly behind the light channel.
For side marker lights, an additional two lengths of 2 core cable need to be run from the junction box, up through the conduit to the spring hanger. Take one cable under the chassis rail and behind the front of the guard. "P" clip (see photo) the cable in appropriately hidden positions to prevent the cable from being snagged by either the tyre or debris flung up from the road. For the other cable you need to "P" clip one cable along the cross member to the right hand spring hanger and again take under the chassis rail up to the light position. Drill the appropriate holes for mounting the light and for the cable to pass through the guard.
Crimp connectors are the most convenient method for joining the wires to sealed lights with attached wiring.
Pass the plug end cable through the cable hole drilled in the top or side of the drawbar and slide a suitable sized rubber grommet over the cable to prevent any chafing of the cable where it passes through the drawbar.
Trim the length of cable so that the cable can move with the trailer behind the tow vehicle without being stretched or kinked, but not too long that it will dangle too close to the ground.
Slide any plug sleeve or nut, that came with the plug, over the cable, then strip each end of the plug wires leaving approximately 10mm bare wire, fold the bare cable in half and enter them into the plug connector in the correct sequence as per the chart above. Tighten the screws snugly but do not over-tighten. Screw the cable clamp down to prevent the cable from pulling out and fit any sleeves, nuts or covers that came with the plug.
If possible, check all your lights by hooking the trailer plug up to your tow vehicle. If you don't have a mate to help you check your brake lights, grab a mirror and position it behind the trailer where you can see it from the tow vehicle.
Now is a good time to fit the springs and axle to the trailer as this is the last time you will be able to work on your trailer running gear without having to get on your back.
Prepare a very clean surface and hand pack your bearings with grease, take your time, the more you can work the grease into the bearings the better.
Over a clean axle, slide the seal retaining washer and seal onto the axle shoulder. Fit the larger inner back end bearing into the hub and tap on the seal wear ring. Grab a good handful of grease and apply it to the inside of the hub and slide the hub over the axle until the back bearing rests against the axle shoulder and seal.
Check that the seal is fitted into the hub and slide the smaller front end outer bearing into the hub.
Fit the washer and castle nut and tighten the nut up until resistance is felt. Give the nut a quick nip and then back off approximately 1/4 of a turn or until the slot in the castle nut lines up with the hole in the axle.
Check that the hub rotates freely and fit the split pin through the castle nut and axle and twist to lock in place.
Tap on the dust cap and repeat for the other hub.
Lay the axle on the ground under your trailer with the spring holes facing upwards. Slide the "U" bolts under the axle in around the position where the springs will sit.
Position the springs over the axle so that the spring centre bolt fits into the holes in the axle.
Fit the spring plate and "U" bolts together and lightly tighten up.
Twist and lift the axle to inset the tail end of the springs into the slippers and then lift the springs so they are in the spring hangers. Bolt the springs into position and do up the lock nuts. Loosen the "U" bolts and give the axle a bit of a wiggle to make sure everything is aligned correctly. Tighten everything up securely. When tightening the "U" bolt nuts, it pays to tighten each nut a little at a time, working your way around the four nuts.
Plywood decking is a versatile and hard wearing decking material. It is relatively cheap and easy to replace if it gets damaged. Plywood normally has two graded faces, with one face being better than the other. For other decking options, see the "Trailer Decking" page.
For trailer purposes a "CD" grade of plywood is more than suitable. It does pay to handpick your plywood from the merchant if possible, as there may be a few imperfections that pass the "C" grade but would look un-slightly on your trailer.
Before positioning your plywood on the trailer, mark the positions of your cross member centres along the side of the trailer above the level of where the plywood will sit.
Lay your the main sheet of plywood against the side furthest from the deck joiner, adjust the sheet so that it is level with the front crossmember and rear light channel. Clamp sheet into position.
Measure the gap in the deck for the remaining sheet (double check measurements at both ends and in the centre of the trailer) and cut the second sheet to fit.
Lay this in position with the mill edge (the uncut edge) against the first sheet of plywood and clamp into position.
With a string line or a straight edge, mark the sheet across the width from the marks on the side panels.
Mark out evenly across the lines spacing the hole centres at approximately 200mm apart both along the cross member marks and down the outer edges and the join.
There are a couple of options for fastening your deck to your chassis. Rivets have been used for many years, but after a couple of years of carting loads around, rivets tend to fail and pop out. By far the best option is self tapping countersunk screws and if you have a good grunty electric hand drill, this job will not take long. For a 17 to 19mm deck thickness, 8G x 25mm screws are ideal. A 3.5mm hole needs to be predrilled and then the screws can be driven in by either hand or with the electric drill and screw attachment.
It pays to start at one end of the trailer and work your way down to the other end to prevent any buckling of the deck.
As with all timber, the plywood deck will swell and shrink depending on how wet or dry the environment is, and you may find over time, the occasional screw breaking from this action on the deck. If this does happen, increase the size of the replacement screw to a 10G x 25mm.
Once the deck is screwed down, give the deck a good going over with an orbital sander to take off any high spots.
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