Used Tractor Unit Buying Checklist: What To Check Before You Buy
A practical checklist for buying a used tractor unit in the UK: paperwork, MOT history, chassis, fifth wheel, tyres, brakes, cab and test drive.
Buying the right used tractor unit can keep your business running for years. Buying the wrong one can mean weeks off the road. Take this checklist with you when you view a truck, and do not be afraid to take your time.
1. Paperwork First
Before you look at the truck itself, make sure the documents match.
- V5C registration certificate: the VIN and registration should match the chassis plate on the truck.
- Plating certificate (Ministry plate): shows the gross vehicle weight and gross train weight the truck is plated for.
- Annual test certificate and MOT history: look for repeat failures and advisories. Our guide to checking a used HGV's MOT history and paperwork explains what to look for.
- Tachograph calibration: the calibration plaque should be in date, as calibration is needed at least every two years.
- Service records and inspection sheets: regular safety inspections from a fleet are a very good sign.
2. Specification And Emissions
- Confirm the Euro rating, especially if you work in or near a clean air zone. See our Euro 6 vs Euro 5 guide.
- Check the axle layout. A 4x2 suits 40-tonne work, while a 6x2 is needed for 44 tonnes on six axles. Read more in 4x2 vs 6x2 tractor units.
- Check the power, gearbox type, cab size and any equipment you need, such as a hydraulic tipping kit.
3. Chassis And Fifth Wheel
- Look along the chassis rails for cracks, welding repairs or heavy corrosion.
- Check the fifth wheel for wear, play in the jaws and a working release handle.
- Look at the condition of the catwalk, suzies and susie gantry.
- Check for oil and fuel leaks underneath, especially around the engine, gearbox and axles.
4. Tyres, Brakes And Suspension
- HGV tyres need at least 1mm of tread across three quarters of the width. Uneven wear can point to alignment or suspension problems.
- Check for matching tyres across each axle.
- Ask about recent brake work and look at the latest brake test result on the inspection sheets.
- Listen for air leaks once the system is up to pressure, and check the air suspension raises and lowers evenly.
- On a 6x2, check the lift axle raises and lowers correctly.
5. Engine And Emissions Equipment
- Start the truck from cold if possible and watch for heavy smoke.
- Check there are no warning lights on the dash, particularly for the DPF, AdBlue or engine management.
- Look at the AdBlue tank and ask when the DPF was last cleaned or regenerated.
6. Cab Condition
- Check the bunk, seats, heater, air conditioning and night heater all work.
- Make sure the mirrors, cameras and lights are working and undamaged.
- High mileage with a well-kept cab often points to a single careful driver.
7. Test Drive
- Drive the truck with a trailer if you can, as faults often only show under load.
- Check the gearbox changes smoothly, including on hills, and the retarder works.
- Listen for knocks from the driveline and check the steering runs straight.
8. Ask The Right Questions
- How many owners has it had and what work did it do?
- Why is it being sold?
- Is there anything the seller knows needs attention soon?
- Can you see it on a ramp or pit?
View A Truck With Us
Every truck we sell is checked over before sale and listed with its VAT, MOT and Euro rating. You are welcome to view any vehicle at our Swadlincote yard, seven days a week from 8am to 6pm. Browse our used tractor units and trucks or book a viewing.