Consumer Reports: Beware of Aftermarket Replacement Parts

What the video shows is nothing short of disturbing. In the first part, the Ford-certified bumper hits the wall and bounces back virtually unharmed. In the second part, the knock-off bumper hits the wall and explodes under the pressure, splintering into a thousand plastic shards. 

The stark difference is due to the plastic materials that make up each bumper. The Ford is a composite of polycarbonate polybutylene terephthalate, or PC/PBT. It’s is a relatively elastic plastic that can deform and bounce back to its original shape. The knock-off is made of acrylonitrile butadiene styrene, which is brittle. The knock-off bumper uses a non-spec plastic despite having the words “PC/PBT” disingenuously printed all over it. 

The outcome is that the aftermarket bumper will not perform the safety function it was designed to perform — namely, to protect a vehicle from structural damage in a low-speed impact and to cushion the blow to passengers in a high-speed one. 

CAPA blames the above incident on a lack of standards in the aftermarket parts business. Non-manufacturer-built replacement parts became popular in the 1980s as auto insurers looked at third-party parts as a relatively cheap way to keep costs down, CAPA says. Some insurers have since then suspended the use of third-party bumper replacements in light of the study.

Video: Knock-Off Bumper Part “Explodes” in Crash Test (Consumer Reports)