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Original Design

The original made-in-US aluminium trailer has a single axle with 16” tyres. As well as being light, its simple design, effective against salt water corrosion, includes a torsion bar axle system and disk brakes.




The torsion bar main axle.

Disk Brake

The original hydraulic cylinder is simple and effective. It has a 12V relay which when reversing, redirects the oil back into the oil tank. This releases any oil pressure on the disc pads making reversing easier. No need to get out of the car to engage any mechanical reversing lock.


The original mudguard and the wood bracket covered with marine carpet.




All alterations done to the original trailer were implemented to meet Australian Standards and where possible, aluminium components selected and used to keep weight down. Eventually disc brakes were added to all axles and a new Electric/Hydraulic brake system installed as the GVM exceeded 2000Kg.

Double Axle

Electric/Hydraulic Brakes

No More Grease

Lift Brackets

Electric Winch

Skid Strip and Front Guides

Double Axle

Single axle is effective but can be troublesome and unsafe touring around Australia. Also finding a replacement US made tyre in the outback can be very expensive not to mention availability of stock.


The solution is two axles with standard light truck types. Replacement is available everywhere.

New lightweight plastic mudguards and the aluminium brackets.

Custom made second torsion bar axle


Mudguards securely mounted on the trailer frame.

Both axles strategically placed to correctly balance the total weight of both boat and trailer. The second axle did not have brake callipers at first but were added later due to the GVM of boat and trailer exceeding 2000Kg.





Electric/Hydraulic Brakes


With all the added weight on both boat and trailer, the Tare Mass has now exceeded 2000Kg. In Australia, such trailer requires brakes on all axles and an assisted brake control system installed. In NZ it's 2500Kg before such modification is required. Are we in Oz land more safety conscious than the Kiwis or it's just another revenue raising culture that is constantly being implemented onto anything that moves on the road. Who knows!


I've chosen the US made Dexter Electric/Hydraulic combination which is more suitable for boat trailers than all electric systems. Electric relays on the callipers can be very troublesome when immerse in water. Eventually they will corrode and become useless. 


The Boat/Trailer on stands ready for the work to commence. Although the first axle already had disc brakes, this upgrade was an opportunity to do some maintenance, mainly rust treatment and prevention.

The new Dexter Electric/Hydraulic components.



Building the aluminium brackets for the Break Away 12V battery.

The Break Away battery ready to be wired.

About here should be perfect to mount the Dexter unit.




For security reasons, I tap the mounting holding screws into the unit. This makes it harder for anyone with intention to steal the unit. Precaution is better than cure.


The breakaway unit is mounted next to the reservoir.


Drilling holes for the tow coupling.



The 3500Kg tow coupling is bolted onto the frame.

New disc brakes ready to be tested.


The blue wire connects to the dash board controller through the trailer plug and provides the signal to operate the Dexter unit.


The wiring of the system. The Dexter Electric/Hydraulic system requires a controller mounted on the dash board of the towing vehicle to work properly. Click here for details

When connected to the back of the towing vehicle, the red Anderson plug provides the 12V to power the Dexter unit as per the diagram.


To ensure proper connection of the blue wire for the signal from the Electronic Brake Controller on the dashboard to the Dexter Unit on the trailer, I've used two pins of the trailer plug:

Pin 2 Reversing Signal

Pin 5 Service Brakes.

Both plugs on the towing vehicle and trailer are configured the same. Over time, should the pins become corroded, two is better than one.



Car, Boat and Trailer on weight bridge.


Trailer on weight bridge. The weight is needed for the new compliance plate.

Boat and trailer on weight bridge. This is to give me an indication of the tare mass and the GVM for the compliance plate and the updated VIC Road registration.


No More Grease

Oil vs. Grease for boat trailer bearings. There is a lot of debate around the world of which system is best. Both have advantages and disadvantages.

In my opinion, it can be summed up as a personal choice. In comparison to a caravan or other on road RVs, a boat trailer gets immerse in water when launching. Water inside a bearing can be deadly. Grease is denser than oil and in theory provides a better barrier stoping water reaching the bearings.  On this argument, many boat trailer owners hesitate to change from grease to oil lubrication. This argument is fair so long as the bearing buddies are regularly greased as a standard maintenance procedure.

On the other hand oil lubrication of bearings requires less maintenance and do actually run cooler. But the major argument for avoiding this lubrication system is what happen if the oil cap comes off. The oil will spill out and the bearings will eventually run dry. Heat will cause considerable damage to the system. However, if a grease lubrication cap comes loose, the grease will not spill out and will provide lubrication of the bearings for a longer period than oil. Another fair argument.

Combining both grease and oil might be the ultimate solution.

I favour the combined grease and oil lubrication system for it's low maintenance properties. The chance of a cap coming off, if installed properly is a remote possibly. Everything has a risk and there is no doubt that a cap can come off and cause damage to the bearings and if this happen in the middle of nowhere, it can be a real worry. Like carrying a spare tyre, there is no harm in carrying a spare cap and spare top up oil bottle.

The success of this method of lubrication depends on the quality of the parts and components used and provided the correct procedures are followed.


A new oil cap. Note the glass front which is another advantage of oil lubrication vs. grease. Oil turning white is an indication of water contamination. Such effect can be seen through the glass and quick action taken to avoid bearing damage. You can't visually see if water has infiltrated a grease system.

The glass also provide a visual view of low oil level which can easily be top up through the oil plug.

The back seal is one of the most important component of an oil lubrication system. This is where water can get in and damage the bearing. A stainless steel seal ring (photo below) is an absolute must to ensure that the spring inside the seal run smoothly over the axle spindle. The original axle on the Macgregor trailer did have one installed but the new axle needed a new one.

Stainless Steel seal ring is a must in an oil lubrication system.

Stainless Steel seal ring ready to be mounted on the axle spindle.

The completed oil cap. Loctite® and marine grease are used to seal the unit onto the hub.


Instructions for grease/oil lubrication:

  1. Ensure the sizes of the axle and the rear seal are correctly matched. Ensure that the correct oil seal is used. It must have a spring garter.
  2. Disassemble hub and wash all parts thoroughly with degreased ensuring all traces of grease are removed.
  3. Ensure that all parts are in good working order.
  4. Pack inner bearing with high quality marine grease.
  5. Install the grease packed rear bearing and seal arrangement.
  6. Apply a layer of grease where the rubber of the rear seal will sit to ensure a lubricated sealing surface. This will reduce the chance of rust on the axle moving to the rear seal area.
  7. Pack outer bearing with high quality grease.
  8. Install the hub on the shaft followed by the grease packed outer bearing, washer, nut and split pin.
  9. Apply a small bead of Loctite® around the smaller circumference of the oil cap.
  10. Fit the cap using a block of wood or nylon hammer but leave a small gap.
  11. Apply a layer of marine silicon between the gap before completely hammering the cap to the hub.
  12. Remove filler plug and insert approximately 50ml of gearbox 80/90 oil.
  13. Allow the oil and grease to mix and repeat until the oil level settles halfway through the lens.
  14. Replace the filler plug and tighten to firm.
  15. Never fill more than HALFWAY up the lens.

Lift Brackets

As can be seen from this photo, when retrieving, the bow hits the V shape bracket and need to climb on top. At this stage, the boat is very heavy with the water ballast still full.


Whether using the engine or the manual winch, it requires quite an effort to move the boat forward onto the V shape.

The final resting place of the bow.

The solution. Add lifting brackets across the trailer rails to glide the boat onto the V shape and also install an electric winch.

Making a strong aluminium bracket with gliding PVC strip to glide the boat higher on the trailer when retrieving.


The finish bracket adds extra strength to the trailer and stops the dagger board for accidently coming loose and falling down.

Note that the lift brackets do not provide any support to the boat load when trailing.

Another bracket to guide the bow straight onto the V shape.


Electric Winch

The electric winch set and the original hand winch in the middle

Building an aluminium base to mount the new electric winch on. The complete system is designed to be easily installed and removed from the trailer.

A long cable running from the car battery through a 150A fuse ending with an Anderson 100A plug at the back of the car.

Testing the winch.

The original manual hand winch.

Electric winch replacing the hand winch. Note the two butterfly nuts to allow easy removal of the unit.

Side view of the electric winch.

Making a new bracket to mount the old hand winch.




New bracket for the hand winch ready to be welded.

Welding the hand winch bracket.

Two winches in place.

When the electric winch is installed, keeping the hand winch is a safety feature in case the electric one fails. Most of the time the manual winch stays on the trailer and due to the lift brackets, retrieving is much easier. However, there are ramps which can be very steep and the electric winch is then installed.


Skid Strips and Front Guides

Adding blue stripes over the carpeted wooden brackets.

Bending aluminium bracket for the front guide.

The front guide installed. This makes retrieving easier especially in high winds when the boat is pushed sideways off the trailer.

Blue strips added to the lift and V shape brackets

The middle and side wooden brackets are wrap in marine carpet.

The weight of the boat has squashed the wood and eventually the carpet will be wormed out.

The solution is to replace the two middle wooden brackets with an aluminium base holder and double blue strips for strength.

The completed middle aluminium base holder.

This would help the boat to slide easier on the strips.

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Copyright © 2015, Sylvio Belcourt