Home Car Mechanic
Unfortunately too often people decide to go ahead with mechanical repairs at home without using a manufacturers guide, often this is simply because their car is too old to request a copy from their dealership, or they don’t want to pay for one created by an independent publisher.
While most home mechanics with a lot of experience, or who have received past advice, will always use the manual, many new home mechanics or individuals who believe they know what they are doing will forego this, and this is a critical mistake.
The majority of home mechanics who don’t follow a manual end up with endless problems in their repair. While some repairs may seem straight forward, there are still critical steps required that need to be supplied from the manufacturer in order to repair the car correctly.
The importance of torque settings:
The most important part of vehicle repair is torque settings, which apply to every single nut and bolt on the car. In fact, each nut and bolt on the car is designed to operate at a specific torque strength. Torque is simply how much pressure you apply to each nut and bolt, to tighten it to the exact required amounts, from fenders to the crankshaft, each have varying levels of strength that need to be applied in order to ensure that part operates trouble free and without causing damage both now and into the future.
Smaller seemingly insignificant bolts are still be a leading cause of failure:
You may think something like a fender bolt is insignificant, however, to ensure the bolt does not come loose in the future, you need to apply the manufacturer supplied bolt at the correct strength to ensure it stays on the car. Under-tightening these will mean they will easily vibrate loose over time.
Overnighting one of these bolts may seem the most common method to most home mechanics with little to no experience, however this also causes the problem of causing too much weight on the nut thread which is a part of the body shell, once this is stripped, removing the bolt in future, or placing another bolt in, will become impossible without re-tapping and threading the hole again for a larger, non manufacturer specified bolt.
If your response to this is “so what?”, you may want to reconsider this unless your car is destined for the scrapyard, put simply, it causes you more problems in future which can be completely avoided by a little thing called the specified torque setting. Spending a little bit more on a complete set of socket torque wrenches, which come in various strengths and sizes, and finding yourself an original factory service manual (produced by the manufacturer at the time the vehicle was built) or an quality after-market publication (where a secondary owner has measured the strength of each nut and bolt at removal), ensures your car retains the original settings and will last much longer in the future.
On more critical mechanical components, torque settings are absolutely vital:
Of course we have only covered something basic here about torque settings, but look a little further to more critical aspects of the vehicle, such as if you were to fit a intake or exhaust manifold, where you need to ensure a proper seal between the cylinder head and the manifold to prevent leaks, or even more critical a cylinder head removal, which not only requires each bolt to be removed in a specific sequence, but also requires each bolt in that sequence to be looses to one specific torque setting first to loosen each one, then another to completely remove the bolt, the same being required in refitting, without the service manual you will have absolutely no chance of the repair lasting longer than a few hundred miles if you are lucky.
Workshop and factory service manuals are the best source for torque settings:
Obtaining a factory service manual can be done by enquiring at your local dealership, most manufacturers are happy to provide you a copy either via a download link on their website, a special order, or even a photocopy of their originals if they still have them on hand. You can also obtain factory service manuals for older cars in pdf format for free online at websites such as AllCarManuals.com, most of the manuals on these sites the dealerships can no longer supply, so it is a good resource for owners of older vehicles.
If obtaining a factory service manual is not possible however, there are normally a variety of after-market books by independent publishers and authors, which can do the job as close as possible to the manufacturers advice, the most common place to buy these today are sites like eBay, but some auto shops may carry them provided your car is popular or fairly new.