Chassis, coupling and suspension: what to check before you sign for a used off-road van

I had a bloke ring me from a servo car park in Ceduna a few years back, phone camera pointed at a chassis rail, asking if the crack he was looking at was "just surface rust." It wasn't. It was a fatigue fracture running half the depth of the rail, on a van he'd paid a deposit on that morning. He didn't buy it. Good thing too, because that rail would've let go somewhere around the Nullarbor roadhouses and he'd have been waiting on a low loader for a fortnight.

That's the thing about buying a used off-road van. The cabinetry, the fridge, the shower — all of it looks the same whether the rig's done 15,000km of gravel or 150,000. What actually separates a van that'll get you round Australia from one that'll leave you stranded is underneath, and most buyers never get down there with a torch and a decent look.

Twenty years fixing rigs before I started writing about the tracks they broke on taught me one thing above all: paint doesn't tell you anything. A fresh coat of undercoating over a chassis is sometimes protection, and sometimes it's someone hiding a repair they don't want you asking about. This is the walk-through I actually do, in the order I do it.

Start with the chassis, not the interior

Get the van up on stands or a hoist if the seller will allow it — a decent used-van dealer should have no problem with this, and if they do, that tells you something on its own. Run a torch along both chassis rails from the coupling to the rear bumper bar. You're looking for rust bubbling under paint, welds that look different in colour or texture to the rest of the rail (a sign of repair), and any cracking near the A-frame junction or around the axle mounts, which is where off-road vans cop the most flex.

Galvanised steel chassis are the standard on most decent off-road vans now, and they should show even, dull grey zinc, not patchy or flaking. If you see paint applied directly over what should be galv, ask why. Sometimes it's cosmetic touch-up after a repair. Sometimes it's covering rust that started under a rock chip and got worse before anyone dealt with it properly.

Check the A-frame itself for any sign it's been straightened. A van that's had a heavy front-end hit — reversing into a bollard, a jack-knife at low speed — sometimes gets the A-frame pulled back into shape rather than replaced. Look for uneven weld beads, paint that doesn't match, or a coupling that sits slightly off-centre when you sight down the drawbar.

The coupling and jockey wheel tell their own story

A worn coupling head is one of the cheaper fixes on this list, but it's also one of the easiest to spot neglect through. Grab the coupling and try to rock it side to side and up and down on the ball — some play is normal, but excessive movement means the coupling's worn past where it should be replaced. Check the safety chains are rated for the van's ATM, not just whatever chain was lying around a shed, and that the shackles aren't stretched or showing wear marks from years of dragging on the ground.

The jockey wheel clamp is a small thing that ruins a lot of days. If it's sloppy or the wheel wobbles under load, that's wear that'll get worse, not better. I've had our checklist for the actual hitch-up process covered in detail elsewhere — worth reading alongside this if you're new to towing (the hitch-up checklist that stops driveway disasters).

Suspension: leaf springs versus independent, and what wear actually looks like

This is where I see the most disagreement between buyers and sellers, mostly because people don't know what normal wear looks like versus what's a problem. On leaf spring setups, check for flattened or cracked leaves, especially the main leaf, and look at the shackle bushes for perishing or excessive play. A shackle that's seized solid is almost as bad as one that's sloppy — it means the spring can't articulate properly and every bump gets transmitted straight into the chassis instead of being absorbed.

Independent suspension setups — trailing arm, torsion, or coil-over designs — hide their wear better because there's no obvious leaf to look flat. Check the rubber bushes at each pivot point for cracking or excessive movement, and look at the shock absorbers for oil weeping down the body, which means they're on the way out. I wrote a longer comparison of the two systems and what actually matters on corrugations if you want the full breakdown (independent suspension vs leaf springs), but the short version for a used van inspection is: any play in a joint that shouldn't have play is a cost you're about to inherit.

Wheel bearings and axle seals, every time

Jack each wheel off the ground — one at a time — and grab the tyre at the 12 and 6 o'clock positions. Rock it. Any detectable play means the bearing is loose, and on a van that's been sitting on a yard for months, that's common enough that I check it as standard rather than as an afterthought. Spin the wheel and listen for grinding or roughness. A bearing that's been run hot once, even if it was repacked afterwards, is never quite as good as one that hasn't.

Check around the hub and axle seal for grease staining on the inside of the rim or on the brake backing plate. That's a sign the seal's failed at some point, and depending how long it went unnoticed, it could mean contaminated brakes as well. I've covered the full bearing inspection process separately with more detail on what failure actually looks like on the road (wheel bearing checks: how to spot trouble before it costs you a hub), and it's one of those jobs worth doing properly rather than trusting a seller's word that "it was serviced last year."

Brakes, and why a clean underside can be a red flag

Electric brakes on a van need to be checked for even wear across both sides and no sign of the magnet dragging unevenly on the drum. If one side's magnet face is worn at an angle, the brake controller's been set wrong for a long time, or the brakes have been dragging on one side without the previous owner noticing. Either way it's cost you're picking up.

Here's the bit that surprises people: a spotless, freshly cleaned underside on a van that's supposedly done serious touring kilometres is sometimes a bigger worry than a dusty, honestly grubby one. Dust and grime in the right places — settled evenly, consistent with genuine use — tells you the van's been where the seller says it's been. A chassis that's been steam-cleaned the morning of the sale sometimes means someone wanted a good look underneath covered up. I'd rather buy a van that looks like it's actually been to the Kimberley than one that's been detailed to look like it hasn't.

If you want the fuller checklist on brakes specifically, before you tow anything long distance, I put together a separate rundown that's worth running through even on a van you already own (the pre-trip caravan brake check most tourers skip).

Ask for service history, and be sceptical if there isn't one

A used off-road van with no service records isn't necessarily a bad van, but it means you're doing the due diligence the paperwork should've done for you. Ask specifically about bearing repacks, brake magnet replacement, and any chassis or suspension repair work. If the answer is vague — "yeah it's all been done" without dates or an invoice — treat every finding above as unverified and price your offer accordingly.

For buyers planning to actually take a used van somewhere remote, I'd treat this whole inspection as step one, not the whole job. A proper electrical check matters just as much and is a separate skill set again (off-grid electrical inspections: what a pre-purchase check should actually cover), and if you're planning a Kimberley run on a van you've just bought, get it serviced properly to a checklist built for that specific trip, not just a generic once-over (the pre-Kimberley service checklist a workshop won't do for you).

What I'd walk away from

Any crack in a chassis rail, full stop — repaired or not, I want an engineer's report, not a mate's word that it's "sorted." Excessive coupling play combined with a poorly maintained-looking jockey wheel, because it suggests the whole front end's been neglected. Grease on a rim from a failed seal with no record of it being addressed. And, honestly, a seller who won't let me get the van up on a hoist for a proper look. That last one isn't a technical fault, but in my experience it's the most reliable warning sign of the lot.

None of this is complicated. It's a torch, a jack, and about forty minutes of getting your hands dirty before you hand over a deposit. Compare that to a chassis repair bill somewhere past Coober Pedy, and it's the easiest forty minutes you'll spend on the whole purchase.

— Dan "Dusty" Whitlock, 4WD & Tracks Editor