Auto Repair Manual Illustrations
Mechanical illustrations and drawings are difficult to understand especially when there are highly technical notes that describe them. Auto repair manuals will have many of those illustrations because of disassembly and re-assembly of parts that have more internal parts within. The drawing is a 'blown-apart' illustration of an assembly. There are steps to be followed, like say for a starter motor. Not following the steps and precautions can cause failure after re-assembly.
The blown-apart illustration shows all the integral parts of an assembly down to the smallest screw, nut, washers, clips, circlips and sometimes cotter pins. The smaller parts are shown around the larger parts of an assembly. Most of the time they are either identified by part name or part number. The parts in the illustration will have broken lines that point to where it comes from or where it was removed. In disassembly, it usually starts from holding (retaining) screws and nuts to take apart what is inside. For some parts, sequential numbers are put as they will need to be disassembled in that manner. It will be the reverse sequence for reassembly of the unit. The vehicle part is usually described before or immediately below illustration. It would also contain instructions and special tools, if any, that would be needed. Bolts and nuts have specific tightening torque. Take note of parts that might need greasing or oiling before installation. Water tight assemblies frequently require sealants to prevent water to seep in or leakage.
On the illustrations, it is rare for the repair manual/automotive repair manuals to mention if a part is plastic or rubber. Rubber parts are often referred to as "o" rings, grommets or rubber cups/caps. During disassembly and using an illustration for reference, it is best to position the part as shown. In taking apart the pieces, if possible set them aside in a similar way shown on the illustration to make sure you would assemble correctly after repairs. Some screws, bolts and nuts look very similar but could differ slightly in length and diameter.
A word of precaution when tightening screws, bolts and nuts against a plastic, aluminum or rubber parts: Auto repair manuals/bentley repair manuals do not give torque specifications for tightening these. Tightening should be sufficient only for the part not to turn loose. The metal screws, nuts or bolts should not 'dig' or embed into those soft materials. Over tightening could cause the materials to break, warp or tear away. If applicable, use a lock washer to ensure bolts and nuts will not come loose.
About the Author:
Mike has been working on cars and trucks since he got his first Olds 442 in the early 70's. Since then he was worked on many vehicles and is deeply interested in electronics and the new computer controls of todays vehicles. While it might seem they are limiting the DIY'r he thinks just the opposite. With the right OBDII Code Reader and Haynes repair Manual you can do far more than the days of screwdrivers and timing lights.