Safety advocates do NOT recommend buying used child safety seats. There is no guarantee for safety when purchasing a used car seat at a garage sale, flea market or thrift store. These seats may be expired, have missing parts, be damaged, or may have been recalled. There is no way of knowing if these seats have been in a crash and if they had received damage that can't be seen with the naked eye.
Take the following steps before you decide to use any used car seat:
Verify from the previous owner that the car seat has never been involved in a vehicle crash. Never use a seat that has been involved in a crash. The seat may not function properly and may fail to provide adequate protection in another crash.
Confirm that the car seat has all its parts including hardware, harness and tether straps, restraining clips and manufacturer's instruction booklet. The car seat cannot be used unless it is assembled as shown in the instructions. Many of the parts are available from the manufacturer. The instruction booklet provides detailed, illustrated information on how to correctly install and use the seat. If the instruction manual is missing, call the manufacturer to get one.
Check the condition of the car seat and look for any evidence of cracks, chips, or stress lines in the shell; warping, rust or broken rivets in the frame; cuts, frayed edges, broken stitches, or twisting in the harness or tether straps; tears in the padding; or broken buckles. If there is any visible damage, don't use the car seat.
Check the date that the car seat was manufactured. This can be found on a printed label somewhere on the seat. Older seats may not meet new federal safety standards or have new design features that improve installation and use. Don't use a car seat that is more than six years old unless permitted by the car seat manufacturer. Many car seats have an expiration date that can be found on the seat or in the owner's manual. Car seat manufacturers won't warranty their car seats after the expiration date.
Find out if the car seat has been recalled by calling the manufacturer or by checking the recall list at http://www-odi.nhtsa.dot.gov/owners/SearchSafetyIssues. You will need the name of the car seat manufacturer, model number or serial number and date that it was manufactured. The car seat should not be used until the recall issue has been addressed.
Check the weight and height limits of the car seat to be sure that it is appropriate for your child.
If you're not sure about the safety of the used car seat, don't use it. Don't risk your child's life.