Buy the assembly, not the component
This is the single most useful buying rule in a heavy-salt state and it runs against every instinct about saving money.
The cost of a repair here is dominated by removal. A wheel bearing pressed into a corroded knuckle, a caliper bracket on bolts that have been sitting in brine for a decade, a strut whose lower bolt has bonded itself to the sleeve — the new part is the cheap half.
So the arithmetic changes:
- A complete hub assembly rather than a bearing to press into the old knuckle.
- A loaded caliper with the bracket and hardware rather than a rebuild kit for one that is already pitted.
- A complete strut assembly with the spring and mount rather than a bare damper needing spring compressors on rusted hardware.
- A control arm with the ball joint rather than a joint pressed into an arm whose bushings are the same age.
Brake lines are the failure that matters
Steel brake line corrodes from the outside in, hidden by clips and by the underbody, and it does not announce itself. It fails when full pressure is applied — which is exactly the moment somebody needed it.
Signs worth taking seriously: a pedal that has gone slightly longer over a season, a fluid level dropping with no visible leak, and visible scaling anywhere on a line's run. Any of those is an inspection of the whole line, end to end, not just the section that is visible.
Replacement here is usually a full line rather than a repaired section, because a line that has corroded in one place has been in the same conditions along its whole length.
What actually seizes
Knowing the list is most of the preparation.
- Wheel speed sensors in the knuckle. Aluminium knuckle, steel sensor, salt water — the classic galvanic seizure. Plan for drilling one out, and buy the sensor before you start.
- Caliper slide pins. Seized slides wear the inner pad and leave the outer one, or the reverse. This is why "the pads were fine on that side" is a symptom rather than good news.
- Exhaust fasteners. Assume every one of them is single-use.
- Rotor-to-hub interface. Corrosion here welds the rotor on and causes runout when it does not.
- Bleeder screws. They round off, and a rounded bleeder on a caliper you were going to keep turns into a caliper you are replacing.
Heat, penetrating oil applied the day before rather than the minute before, and a proper impact tool are the difference between a two-hour job and a snapped stud.
No annual inspection, which cuts both ways
Michigan does not require a periodic safety inspection. Nothing forces a repair on a schedule.
For an owner who maintains a car that is a saving. For a used car buyer it is a warning: a vehicle here can accumulate years of deferred corrosion with nothing ever flagging it, and it will look completely normal from the outside. Underbody condition is the first thing to check on any used vehicle in this state, before mileage and before service history.
Cold, and what it exposes
Lake-effect winters mean sustained cold rather than occasional cold, and cold is what finally reveals a battery that heat degraded in July. Cold cranking amps drop as temperature drops while the oil the starter has to turn gets thicker, so the demand rises exactly as the supply falls.
Start-stop vehicles are more sensitive again, because the system disables itself when the battery cannot guarantee a restart. A car that stopped doing start-stop in November is reporting a measurement, not developing a fault.
Two more cold-weather items worth having right. Coolant tested on freeze point rather than on colour, because a system topped up with water over several years is at a concentration nobody has checked. And washer fluid rated for the actual temperature, since the summer mix freezes in the lines and splits the pump.
Checked