8 Important Tips When Buying a Used Classic
Rust Damage

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This one is very important. Rust issues can be expensive to repair so make sure you avoid a car that has excessive damage. This wont always be the case and not all rust is a deal killer but if you can find a car that is completely rust free, that’s choice! If the vehicle has light surface rust in a few spots, make sure thats where it ends. Search thoroughly and make sure there are no areas of heavy rust. If you come across holes in the body due to rust, if you’re not a metal worker or a hero at bondo, give it a pass. Always check the cowl area under the dash, the floorboards beneath the carpet, the trunk, and the wheel wells. A little surface rust is fine. A lot is a deal breaker.
Interior

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This ones pretty obvious but still should be taken seriously. Cracked dashboards could mean years of sitting in the sun, which is a good tip that the car may have been immobile or busted for a period of time. Look at the seats and see what the damage is to the upholstery. If it’s new or doesnt have any wear and tear, ask if anythings been replaced. Check the moving parts to make sure the seats are cool and that the glove box opens. It may seem trivial but its very important.
Doors and Windows

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Make sure the doors and windows open and close without any issues. Make sure the frame rails are straight and proper. Make sure they provide a good tight seal against the elements, if not, youre looking at replacing hard to find and time consuming seals. When it comes to the elements, you should also check the front windshield and cowl to make sure they don’t leak. This is often forgotten in states like California where it hardly rains. Sweat the little things, check everything.
Shock Towers

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Make sure to check the car’s shock towers and look for metal fatigue and cracks. Separated shock towers are common in classic cars and if you find rust, thats not good. You want a car with structural integrity so pay close attention to the situation and ask lots of questions about the history of the vehicle.
Quarter Panels

Photo: Reddit
You can check these from inside the trunk. Feel around. Do you notice any bumps? If so, it’s likely the Mustang has been repaired using body filler. Pack a strong magnet with you and go over the panels to see if there are any bondo spots. Look for sketchy paint repairs and again, ask questions.
The Door Plate

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Door Data plates on old Mustangs(and other vehicles) offer up the original configuration of the car. We’re talking about body color, interior trim color, body type, DSO (District Sales Office), production date, and transmission type. A good look at the Data plate should reveal how original the Mustang truly is. You can find various Data plate decoders, both online and in paperback format. If the car is missing the door plate you still should be able to find some info out if you review the Mustang’s VIN.
on classic Mustangs look in the following places:
Engine Compartment: On the driver’s side fender apron
Windshield: Inside, passenger side, where dash and windshield meet. Info is on the driver’s side on 1969+ Mustangs
Door Date Plate: On the Mustang’s original door data plate
Note: If you come across a Mustang with a variety of VIN numbers, thats not necessarily a bad thing but cars with matching VINs are generally worth more than those with VINs that don’t match.
Electrical System

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Check to make sure things like the headlights and signals work properly. Check the car’s gauges and see if everything looks proper. A faulty electrical system can be a huge disappointment. If you dont know what to look for, bring a buddy or a mechanic go with you if you are serious about buying a car that day.
Brakes, Drivetrain, and Suspension

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If you’re looking for a car that’s road ready (no major resto work required), you need to make sure it runs smooth and it can stop without any sketchy lapses in the pedal to the braking system.Test drive it and feel the engine as it shifts gears. Listen to the engine and the sounds of the vehicle. You’ve seen the engine, does it match with what you’re feeling as you drive? Make an assessment as you go and take mental notes of sounds and any issues you feel. The road test is critical and if youre new to classic cars, take that mechanic with you and even have him drive it if you must.