Rust Never Sleeps - Trailer maintenance

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Paul Walker
08 October 2015

Many people stow away their boat over winter, however proper care and inspection is essential to ensure springtime does't become an expensive repair exercise.

This applies to your pride and joy; the boat, outboard, trailer and all the electrical gadgets that go with a good unit. There is a big investment here so it seems foolhardy to let it deteriorate and rot over winter when a small amount of effort on your part could head off a lot of potential problems and keep your boat in good nick.


In this issue we will cover the boat trailer, as it seems to be one of the most corrosion prone units in a boating package. Stay tuned to the NZ Fishing World Club online for my tips advice on boat and outboard maintenance in the coming weeks.

The frame

These days most boat trailers seem to be made of galvanised box section steel. Every time the boat is launched salt water fills this box section. As the trailer dries in the car park the salt remains. This is where it does its nasty work by getting into little pinholes in the galvanising.

Over a period of time rust and corrosion will eat your trailer from within unless washed thoroughly (with out fail) every time you launch the boat in salt water. Thorough washing may not stop corrosion but it will slow it down and there are some products that will help effectively combat the corrosion.

Salt Away ( is an excellent salt killing solution, and comes with its own dispenser. Making it easy to attach to your hose and spray into the areas prone to salt build up.


Modern trailers with multi rollers sometimes known as wobble rollers pretty much look after themselves and need very little maintenance. Every now and then after launching the boat spend five minuets checking all the rollers for cracks or wear before you run back to the boat.

Roller replacement is an easy process: Just pull out the split pin, slip off the washer and old roller then replace with the new one and pop back the washer and split pin - job done. Occasionally it might pay to spray some lube such as Inox ( around the rollers.

Hand winch, jockey wheel and tow coupling

The winch is a fairly basic machine and really only needs grease on the cogs and oil on the moving shafts a couple of times over the season (including winter).

Pull out all the winch rope and check to see if it needs replacing. Grease both internal sides of the rope drum while the rope is unwound as a lot of salt water comes in on the rope, which then lies against the drum causing it to rot. If you’re worried about winch handle theft I recommend drilling a small hole at the end of the handle shaft, which can fit a small removable lock pin.

The jockey wheel is similar to the winch; make sure the main shaft and the mechanism it pivots on is always greased. Oil the handle knob and check the tyre for cracks where the shaft goes through (apply some grease to the shaft as well).

Make sure to keep tyres inflated. Next time your gassing up the boat take an extra ten minuets to check the trailer tyres and jockey wheel for pressure.

Tow couplings are pretty important so make sure all is in proper working order here; again grease and oil all moving parts but before you do have a quick look up inside the coupling for any wear that might stop the coupling locking down on the tow ball.

Also check the bolts and welding that hold the coupling to the trailer frame and the safety chain with its D-shackle. Have a good look at the safety chain that holds the boat to the winch frame.


Unscrew and take off both sets of lens covers looking for blown bulbs and corrosion on exposed wiring. Corrosion can be mostly removed by spraying with Inox then after a few hours give the wiring a scrub with an old stiff toothbrush. Rub a little Vaseline around the lens covers to seal them against water.

If the lights are too rotten and leaking it may be time to replace with new L.E.D lights. If so, before you remove the old ones unscrew the top plate of the wiring connector plug and photograph it so you can remember where all the wires go.

After removing the old lights use the old existing wiring to pull the new stuff through the box section frame. Tape the ends of the old and new wires together and pull them out of the exit hole at the coupling end at the front of the trailer.

Now comes the tricky bit; with a blade or side cutters remove about twenty mm of the plastic sleeving and expose the copper wire on all the coloured wires. Twist all of the same colours together making sure the copper wire is tightly twisted locking them together. A small dab of solder may help here.

Following your photograph fit them into their correct slots and tighten the locking screw hard. Now replace the cover plate and plug it into your vehicle and test the running lights, brake and indicator lights.

Hopefully it all works, if not there’s always the local auto electrician.

Replacing springs

Quite often springs may look rusty but they often have a lot of meat left in the steel. A good clean up is all that is required. If it is time to replace them it’s actually not too difficult on most small to medium sized trailers to do it yourself.

It’s not necessary but you may find it easer to take the boat off the trailer before placing a jack under the axel. Remove the wheel, then lift the trailer to a comfortable height and place two safety stands at the front and rear of the trailer. Leave the jack to support the axle.

You should find two ‘U’ bolts over the axle locking into a square steel plate, remove these.

Undo the eyebolt at the front of the spring that locks it to the trailer and as you pull this bolt out the spring should drop down.

The rear of the spring should be slipped into a U shaped saddle welded to the box section - slide the spring forward and remove.  

Take an old spring with you when you go to buy new ones, check the ‘U’ and eyebolts as well. Galvanized springs are better value.

Replacing is a matter of doing the same procedures in reverse.

There should be a locating lug in the centre of the spring, which should slip into a corresponding hole in the axle. Once this is done the ‘U’ bolts can be locked back into the steel plate.

Taking photos sometimes help to remember how it all goes together. With the boat off the trailer check all the nuts and bolts and if any need replacing do them one by one so everything stays in place and the frame doesn’t disassemble its self.

Any nuts that are too rusty to undo cut off with a small angle grinder. Try not to cut the galvanizing.

Wheel bearings

I personally believe this is a job for mechanics or people with good mechanical knowledge as it can be disastrous if you get it wrong. Take your time and take care.

You don’t have to remove the boat from the trailer. Use the same jacking procedure as above. Remove the dust cap or bearing buddy from the hub then dig out as much grease as you can. You will find a split pin through the stub axle with a large castle nut behind remove both of these.

Pull the hub toward you; hopefully it will slide off easily. See the photos for an illustration of the following procedure. Wheel bearings are made up of two parts: cups and cones. The cups should pull out of the hubs with your fingers.

There are two sets of bearings in the hub- front and rear. The cones will require a hammer and punch to remove. Clean once removed (you will notice the rear ones are bigger than the front ones). They will also have coded numbers printed; take the old ones to a local bearing suppler and replace with the same ones.

When installing the new ones first pack the new bearings and inside hub with marine grease. Carefully punch the new cones down inside their respective sides of the hub until they reach the stopping lip.

Place the rear-bearing cup into the hub and slide the whole unit back onto the stub axle.

Once in place the front cup into the hub and replace the castle nut and split pin. With the new bearing buddy’s hammered in nice and tight get that grease gun and pack the hub with marine grease before replacing the wheel- give it a spin, job done!

All the products mentioned in this article such as Rust Away and Inox should all be available at good service centres, chandlery stores, auto stores like Repco or Super Cheap and bearing suppliers.

By getting your trailer up to or better than wof standard over winter you won’t have any trouble over the fishing season, leaving you more time to fish.              

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