Buying used? A rust inspection checklist

Chassis rust is one of the most expensive things to discover after you've already paid for a vehicle. It's also one of the easiest things to check for beforehand if you know where to look. Here's the checklist we run through every time someone asks us to inspect a car before they buy it.

Get it on a ramp or trolley jack — don't trust a walk-around

You cannot properly assess chassis condition standing at the side of a car in a driveway. If the seller won't let you get it up on a ramp, or won't let you bring it to a workshop like ours for a look, that alone is worth noting.

The checklist

• Chassis rails, front and rear — look and press for flaking scale or soft spots
• Outriggers where the body meets the chassis — a common early failure point
• Sills, front to back — tap for a solid sound, not a hollow or crumbly one
• Subframe mounts — check for corrosion around the bolts and mounting plates
• Floor pan — check from underneath and inside for damp patches or filler
• Brake and fuel lines — look for rust scale or pitting along their length
• Rear spring hangers and shackle mounts on 4x4s and vans
• Wheel arch inner liners — remove or look behind them if possible
• Any fresh underseal or fresh paint applied only in one small area — often used to hide recent rust repair
• The NCT/MOT history — check whether corrosion has ever been flagged, even as a minor advisory

Watch for the 'suspiciously fresh' patch

A patch of bright new underseal on an otherwise dull, aged underside is one of the biggest tells in a used vehicle inspection. It doesn't always mean something's being hidden, but it's a strong reason to ask the seller directly what work was done there and to get it checked properly before agreeing a price.

This matters even more on 4x4s, vans and imports

Land Cruisers, Hiluxes and Defenders are notorious for rear chassis rail rot — we cover the specific weak points on /land-cruiser-underseal and /4x4-underseal-ireland. Vans and campers bought for conversion or work use often have hidden corrosion under floor coverings or cladding — worth a proper check before you sink money into a build, see /van-underseal-ireland.

Use a free chassis check before you commit

We offer a /free-chassis-check specifically for this — bring the vehicle (or send us clear underside photos first) before you hand over a deposit, not after. It costs nothing and it's the single best money-saving step in buying anything used. You can also see what other customers found before and after using us on /reviews.

Looking at something this week and want a second opinion before you commit? WhatsApp underside photos to 087 919 2193 and we'll give you a straight answer.