Trailer safety inspection checklist
What an inspector actually looks at on a light trailer, written as a list you can work through in the driveway. Most failures are cheap things that take ten minutes to fix, and cost a second booking if you find out at the station.
What the inspector is looking at
Access Canberra describes a roadworthy inspection as a check of wheels and tyres, suspension and brakes, lights and reflectors, the overall structure and the identifying numbers. It does not check general condition or mechanical reliability. On a trailer, "structure" means the coupling, chains, drawbar, chassis and mudguards, and "identifying numbers" means the compliance plate and VIN. NSW safety checks cover the same ground.
When an inspection is required, and where to book one, is on trailer rego in the ACT, which also covers NSW pink and blue slips for Queanbeyan. This page is only about passing it.
Go over these before you book
Lights and reflectors
Every trailer needs two tail lamps, two brake lamps, two indicators, a number plate lamp, and reflectors at the rear, front and sides. Wider than 2,100 mm or longer than 6,000 mm adds clearance and side marker lamps. Hitch up, run each function, and check for cracked or faded lenses.
Wiring and plug
A 7 or 12 pin plug to the Australian standard. Pull the plug apart and look for green corrosion on the pins. Follow the cable: no chafing where it enters the drawbar, no joins wrapped in tape, nothing hanging low enough to catch. A bad earth shows as lamps that flicker when the indicator is on.
Tyres
The ACT standard is 1.5 mm of tread in a continuous band across the contact width and right round the tyre. Look for cracking in the sidewall, which is common on trailers that sit outside, and for bulges. Both tyres on an axle should match, and the load rating on the sidewall must cover the trailer's weight. Check the pressure against the placard.
Wheels and nuts
All nuts present and tight, no elongated stud holes, no cracks around the centre or the rim. A wheel with rust streaks running out from the nuts has been loose. Spin each wheel and watch for wobble.
Bearings
Jack each wheel, grab it at twelve and six and rock it. Play you can feel, or a rumble or grinding when you spin it, is a bearing on the way out. Grease thrown around the inside of the rim means a failed seal. Bearings fail more trailers at the roadside than anything else: see servicing and repairs.
Brakes
Over 750 kg GTM a trailer must have brakes. Over 2,000 kg GTM they must act on all wheels, work from the driver's seat, and apply on their own for at least 15 minutes if the trailer breaks away. For override brakes, the coupling slide should move freely and the cable and adjusters should not be seized. For electric brakes, test the breakaway switch and its battery. How this relates to your tow vehicle is on towing capacity.
Coupling
A 50 mm ball coupling must be stamped with the maker's name, "50" and a rating of 750, 2,000 or 3,500 kg, and the rating must be at least the trailer's ATM. The latch must lock positively and release at any angle. Check the handle, pin and bolts are tight and nothing is cracked or worn oval.
Safety chains
At least one chain up to 2,500 kg ATM, two above it, mounted one each side of the drawbar and crossed. The chain carries a marking such as 4177-25 on every fourth link; no marking, no provable rating. The chain is fixed to a structural part of the drawbar close to the coupling, and is short enough to stop the drawbar hitting the road if the coupling lets go.
Jockey wheel
Part of "structure" rather than a listed standard. The clamp should hold firmly, the wheel should wind up and swing clear of the road, and the mount should not be cracked or bent.
Drawbar and chassis
Look along the drawbar from the front: it should be straight. Check every weld at the coupling, the chain mounts, the spring hangers and the crossmembers for cracks, especially in the paint. Rust that flakes when you tap it is a fail; surface rust is not. Why some chassis rust and others do not: galvanised vs painted.
Mudguards
Every wheel must have a guard that covers the full width of the tyre. Guards must be solidly mounted, not rubbing the tyre, and without sharp torn edges.
Compliance plate and VIN
The plate must be present, fixed to the trailer and readable: tare, ATM and the 17 character VIN. Wipe it clean before you go. Any VIN stamped on the drawbar must match the plate and the paperwork. A missing or unreadable plate stops the inspection before it starts.
Number plate and its light
Mounted at the rear with the long edge horizontal, no part higher than 1,300 mm, not hidden by a tailgate, spare wheel or ramp, and lit at night. The plate lamp is the one most owners never notice has died.
Load restraint points
Not a listed item, but loose or cracked tie-down rails and hooks count as "structure". Grab each one and pull. Anything that moves at the weld needs re-welding before it carries a load.
What fails most often
Nearly all of it is small. A dead globe or a plate lamp. A plug full of corrosion. A cracked lens on the indicator. A chain with no rating stamp, or one chain where the ATM calls for two. Tyres that have plenty of tread but are cracked through the sidewall from years in the sun. A compliance plate painted over or rusted blank. Bearings with play. A mudguard that has rusted off its mount.
The expensive fails are rarer: a cracked drawbar weld, a seized override coupling, or a chassis rail rusted through. Those are repairs, not maintenance, and worth getting looked at before the booking rather than after. If you would rather have someone check the trailer first, Resort Trailers' rego inspections page explains how that works for NSW trailers.
Where this comes from
Checked 30 October 2026. The kilogram and millimetre figures are quoted from the documents below. Rules change, so confirm them before you rely on them. A trailer's own compliance plate takes precedence where it is stricter.
- Access Canberra: roadworthy inspections (what is included)
- Access Canberra: trailer and caravan registration
- ACT Road Transport (Vehicle Registration) Regulation 2000, Schedule 1: tyre tread (1.56), trailer brakes (1.136 and 1.137), couplings and safety connections (1.155)
- VSB 1 Revision 6, August 2026: lamps and reflectors (6), brakes (8), safety chains and couplings (9), mudguards (10), tyres (12), VIN (13)
- NSW Government: towing a trailer or caravan (brakes, chains, coupling markings, tyres)
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