Frame & Subframe

The clues are behavioural rather than visual. Uneven door and bonnet gaps, a steering wheel that sits off centre while the car goes straight, tyres wearing unevenly within a few hundred miles, or wind noise that appeared after an impact all point at a shell that has moved. The only definitive answer is a measurement on a bench against factory data, which compares control points across the underbody. Get that done before ordering any part in this category, because the measurement tells you which section is actually out and which merely looks damaged.

Sometimes, and only in mild steel with limited deformation and no tearing. Hot formed boron steel sections cannot be straightened at all, because heating destroys the microstructure that gives them their strength, and manufacturers specify replacement or sectioning at defined points instead. Since the two look identical, the decision belongs to a repairer working from published data for your vehicle, not to a visual judgement. Where the answer is replacement, order the exact section by OE number rather than the full rail, which is often more than the repair requires.

The cross car beam is the tube running behind the dashboard from one A pillar to the other. It carries the steering column, the passenger airbag, the heater box and the instrument panel, and it braces the body across its widest unsupported point. The mountings at each end tie it into the body sides. When one loosens or cracks, the whole dashboard develops a knock over bumps and the column can feel less solid than it should. The left and right mountings are listed here as separate parts.

A few are. Underbody panels, heat shields, reinforcement rods and bolt in tow hooks are within reach of anyone with a jack, stands and patience. The rails, cross members and welded assemblies are not, because they are joined to the shell by spot and structural welds, they must be positioned against measured control points, and the joining method is specified by the manufacturer. Fitting one of those without a bench and the data sheet produces a car that looks repaired and behaves unpredictably in the next impact.

It is a low bar mounted ahead of the main structure, positioned to strike a pedestrian below knee height so the legs are swept rather than the body being pulled under the car. It is a regulated feature rather than a styling element, and it is one of the first things bent in a kerb strike or a low speed impact, often without any visible damage to the bumper cover above it. Check it after any front knock, because a distorted one changes how the car behaves in the situation it was designed for.

Read the OE number where it is legible on the old part, or have it pulled from your vehicle identification number. Structural sections are revised constantly and quietly: gauge changes, added reinforcement, altered attachment points, none of which show in a photograph. Battery electric versions of a body frequently carry a completely different floor and rail structure to the combustion version sold alongside them. Where your number returns no result, send it through the quote form so the factory catalogue is checked properly rather than approximated from the model name.

Restore what the factory applied. Weld through primer on the mating faces before joining, seam sealer replicating the original bead shape afterwards, cavity wax injected into every closed section that was opened, and underbody coating on exposed surfaces. Clear any drain holes blocked during the work. Miss those steps and corrosion starts inside the new section within a couple of winters, hidden from view until it matters. On a battery electric platform, confirm the high voltage system is isolated and stays isolated for the duration of the work.

The spread is very wide. Small items such as reinforcement rods, heat shields, tow hooks and underbody panels sit at the low end of the category. Complete welded rail assemblies and large floor cross members sit at the top, since they are heavy, awkward to pack and shipped as freight rather than parcels. The live minimum and maximum are shown in the band at the top of this page. For the larger weldments, a quote is worth requesting because it returns the delivered figure including transport.

No, and mixing the two causes ordering mistakes. The frame is the load bearing shell structure: rails, cross members and floor sections, which on a unibody car are welded into the body. A subframe is a separate bolt in cradle that carries the suspension and often the powertrain, isolated from the body by bushes so vibration does not reach the cabin. Subframes and their crossmembers are listed under suspension, while this category covers the body structure itself. Check which one your repair actually needs before ordering.

On a ladder framed vehicle the recovery point is a bolted or welded hook on the frame rail, listed here as its own part. On unibody cars a screw in eye threads into a captive socket behind a bumper cover cap, which sits in the bumper category instead. Either way, a stripped fitting is replaced rather than repaired, and it is worth inspecting the mounting behind it, since a hook that tore out under load has usually distorted the structure it was fixed to.

Because a rail that resists everything transmits everything. Crush initiators, the pressed dimples and notches you can see along a front rail, make the section fold concertina fashion in a controlled sequence, absorbing energy over distance rather than passing a spike into the cabin. This is why straightening a folded rail is not a repair even when it looks straight afterwards: the initiators have done their single job and the metal is work hardened. Replacement restores the designed behaviour, which is the only version that has been crash tested.

Yes. Every reference exists in the factory catalogue under its OE number, and structural weldments frequently carry no standing price because they move in small numbers and freight varies by destination. Press request a quote on the listing and you receive a current figure matched on the same number, including packing and transport for a long steel part, before committing. Because these repairs are planned around a body shop booking, it is worth requesting the quote as soon as the measurement report identifies the section.