Repairing a vehicle is seldom cheap, and buying used parts can help to bring the price down.

But are they a good idea? And if you’re going to use them, what should you know?

The terms you’re most likely to hear are used, or remanufactured (or rebuilt). Used parts are just that: they’ve been taken off a vehicle and put directly on the shelf.

“Reman” parts have been taken apart, cleaned and inspected, and components have been replaced as needed.

There’s a whole subsection of remanufacturing and rebuilding, and much will depend on who’s doing the work and what term he chooses to use. 

It’s important to know exactly what’s been done to the part, especially if you’re buying it from an individual or a small shop, as opposed to getting something like a remanufactured water pump or master cylinder from a manufacturer’s dealership or a major auto parts chain.

If you can afford the down time, consider having your failed part rebuilt. It will probably cost less than buying remanufactured from a parts store, which has to mark up the product. And since you’ll be getting back the part you sent in, you’re guaranteed it’s the right one for your vehicle.

You might also see “new old stock,” often shortened to NOS. This is most common with older or antique car parts. It refers to a part that was made by the auto manufacturer, but was never sold or put on a car.

These commonly come in their original packaging, since they were often bought by resellers when dealers or parts stores and depots cleaned out their old inventory.

The major benefit to a used part is, of course, the price. In some cases they can also be a necessity, if your vehicle is old or rare enough and new parts simply aren’t available. 

As well, you’re pretty much guaranteed that if it fit on the original car, it will fit on yours. Some reproduction or aftermarket parts aren’t necessarily made to the same standards as the original part. Fastener holes might not line up, or the part may be marginally too large or too small, especially if it was designed to be inexpensive.

When you’re buying a used part, it’s best if you can look at the car that’s donating it. If it came off a vehicle that was retired prematurely due to collision damage (which didn’t affect the part, of course) with low miles on the clock, you should be okay. 

But if the donor car has roughly the same number of kilometres as yours, and your part failed at that mileage, how much life does that used part have left in it?

You’re taking even more of a gamble with a part taken off the shelf, or bought online, unless the seller has a rock-solid reputation for honesty and quality. The part won’t be a bargain if you have to replace it again in a couple of months, especially if your vehicle has to be towed when it fails. 

And there’s always the most overused word in automotive: mint. Your definition may be considerably different from the seller’s, especially if it’s a body panel or other part that’s susceptible to rust.

There are some parts that really shouldn’t be purchased used, because they’re too much of a gamble. These include electronics, which may have been programmed specifically to the vehicle in which they were originally installed; brake parts, which should only be purchased remanufactured to ensure that their seals and moving parts are in top working condition; and safety equipment such as airbags, which are often stolen from vehicles and resold due to their high cost.

When buying a used or remanufactured part, be sure to ask about the guarantee on it. Can you return it if it doesn’t work or doesn’t fit, or fails within a specified period? Get all of this in writing, dated and signed.

If you’re paying a shop to repair your vehicle, and you’ve authorized a used or remanufactured part, ask about labour when it comes to the guarantee. In many cases, the company supplying the part only covers the part itself, not the labour. 

If the piece fails, that’s between the shop and the parts provider, and you shouldn’t be charged parts or labour for the replacement.

One more piece of advice: if you’re planning on buying a used part directly off the shelf, or out of a recycled vehicle, check Transport Canada’s recall database for the year and model to see if that item might have been involved in a recall. 

If it was, and you have no way of verifying its repair or replacement under the recall, you’re best to go directly to a brand-new part.

The chance of a problem may be slim, but if it’s going to cost you money down the road, it’s better to be safe than sorry.