It is so wrong to ask your auto repair facility to install parts that you have purchased elsewhere. Let me count the ways.
It is understandable that a car owner, who is interested in lowering his cost of repairs and is not comfortable with doing the repair himself, may purchase replacement parts from a source other than the repair shop. However, he may not be aware of the ramifications for the shop and possibly his own safety.
The installer of an auto part assumes responsibility for the proper performance of that part. In the event of a failure, it may be impossible to discern whether the cause was a defect in workmanship by the installer or a flaw in the design or manufacture of the part. It may be true that this liability is inherent in the business, but when a consumer removes the profit earned on the sale of the part, it becomes difficult for the shop to justify such exposure.
Not all parts are right.
What happens when an owner-provided part doesn’t work out? This happens every day in repair shops all over the world. The cataloging is wrong. The part is boxed wrong. The vehicle was an early production in 2007, and the provided part is for the late version. Essential parts are missing from the assembly as packaged. The part is made wrong. It bends right instead of left, or it just won’t fit. Ok, ok – enough examples already!
All these conditions affect the shop’s productivity. They diminish the one thing that it considers most valuable while being its most limited commodity – its time. Most likely, when the consumer arranged for the shop to install the part that he acquired, he also agreed upon a labor price. So who pays for all this lost productivity? The consumer might think that he has a firmly agreed upon labor price, while the shop manager’s position may be that the downtime is on the car owner. Resolving disputes like this is not a good way to spend an afternoon.
The argument might be that if these problems are so pervasive, it is just the cost of doing business. This is true, but when the repairer buys the part from his usual network of suppliers, he is able to count on some degree of support in the form of technical assistance or logistical help in hunting down a replacement for the defective part. No such help will be available through an unknown third-party provider.
Parts revenue is essential to shop operation.
Yes, these are horror stories, but there is damage to the shop even when everything goes well. There is a reason that your neighbor or uncle is able to replace a water pump cheaper than Alan & Allen Auto at the corner of 12th and Market streets. That company has an investment in a physical plant, technology, and the training of personnel. It pays taxes, buys insurance, and guarantees its work for 6 months or 6,000 miles.
The platform upon which it operates is based on a revenue stream that depends on marking up (there I said it) the parts it installs. Without that, it cannot produce quality work performed by skilled professionals, which it can stand behind well beyond the road test.
Not all parts are the same.
The current economic climate has caused more consumers to attempt to save money on parts. As a response, parts suppliers have initiated tiered pricing based on the quality of the replacement part. These parts may or may not conform to Original Equipment Manufacturer standards. The same liability concerns that discourage the use of consumer-provided parts are at play in the choice of the grade of the part. In addition, the individual may not be knowledgeable enough to make a quality distinction in a parts purchase.
There is an old saw that has served as advice to auto repair shop owners who are faced with consumers appearing with parts in their hands that need installation. I would guess it goes back to the days of hand cranks and rumble seats. As the story goes, the business owner should respond, “Would you bring your own bacon and eggs to a restaurant and expect them to cook them for you?”