# Automobile Maintenance

Cars are great fun to drive and to mess around with, but they are also powerful, heavy and (statistically) they kill and injure more people than modern warfare.
* So shall we get our hands dirty?
* Chocks and Blocks (of wood).
* Steel-toe safety boots need not be this ugly!
* OK fine! But let's not exaggerate!
* The 4-stroke Otto cycle of most large vehicles.

## Health and Safety
### Driving

Nobody ever died simply by going too fast in a vehicle! Really. Not ever. What kills is the sudden deceleration following a collision!
When driving, 'regularly check how well your brakes are working in this situation, (weather, road-surface, congestion etc.). Remember, when driving, the 'kill zone' where drivers die is just ahead of you about where your headlights shine - from the front fender (bumper-bar) forwards (your safe stopping distance).
In town, this is usually about the distance between two street-lights (around 50 metres or yards): Twice what instructors teach? Why so long? Just because we mechanics are paranoid, that doesn't mean they (machines and people) are not out to get us! Did you know that more people died on USA roads in September 2001 than in the twin-towers attack in 9-11?

### Fixing

Engines are massive, get hot, may contain pressurized boiling water and have big batteries, all of which can cause severe burns. Never wear exposed metal badges or jewellery (remove any finger rings or be sure to wear gloves (recommended anyway) or cover them with sticky tape). That way, they can not short-circuit the battery and cause a spark nor snag in moving parts, OK? (Finger amputation is best done in sterile hospital by a medical team rather than by yourself inside a messy engine bay, honest!)
Vehicles are not only heavy, they are usually fitted with wheels. Always use mechanical wedges ( 'wooden chocks' ) to prevent the vehicle from rolling - do not trust the mechanical handbrake. Not ever! And if you use a mechanical or hydraulic lifting jack, invest in some substantial wooden blocks to take the weight and then remove the jack. Finally - from a safe position, try rocking the body - if it is going to collapse, probably it is better if you are alongside and not underneath, right?

### Personal protective equipment

* Overalls. Sharp screws and rivets may tear heavy denim or cotton clothing, but that is probably less painful than ripped skin. Nudity is distinctly hazardous when working on vehicles.
* Steel-toe boots are a sound investment, and are now lighter, more comfortable and altogether more fashionable than those pictured above)
* plastic goggles if you use power tools - as blindness is not conducive to driving or reparing.
* protective skin cream and disposable rubber gloves are cheap and, if used before starting work, are much less irritating than washing off black oil with gorilla snot or abrasive hand-cleaner. Bleaching soiled skin with household products is not recommended, but is sometimes practised in extremis - always use hand-cream to preserve sensitivity at your fingertips and to minimize damage to your hands.
* Lumber is not really PPE, but at least two triangular wedge chocks and several rectangular body support blocks of different sizes) are the safest support, because, unlike brick or stone which can crumble rapidly, wood tends to splinter gradually and noisily, giving you valuable seconds to escape or fix the problem.
* Protective face masks are essential for some jobs involving smoke or paint a , but, above all,
* Care and attention is always essential, as accidents mostly are caused by a heap of small errors - and we mechanics are not paid to make mistakes, now are we?

## Routine Maintenance

Your car, when it was delivered as a new product, usually has an owner's (user's) manual. This manual will describe the various periodic checks and maintenance suggested by the manufacturer as appropriate to keep the car safely operational with a minimum of problems.
* Checking tire tread.
Tires made for a passenger car or light truck will have straight grooves cut in the tread with small sections cut exactly 2/32nd of an inch higher than the groove. These raised sections are called wear indicator bars or wear bars. If the tread is worn down to the wear bars, the tire is considered unsafe and illegal in some states. Poor tire tread will slip more during braking, give longer braking distance, interfere with ABS, and cause loss of control.
Excessive tire wear is a good indicator of other problems in the suspension. Wear on either side or short tire life shows a need for alignment. Wear on both sides shows underinflation. Wear in the center shows overinflation.
* Checking tire air pressure.
Do not inflate tires to the pressure labeled on the side of the tire. Tires generally have the appropriate air pressure printed on a label inside the drivers door, inside the gas cap, or in the manual. This pressure is based on the load (vehicle weight) placed on the volume of air. The listed pressure is for an unloaded vehicle, based on sprung (above the spring) weight and a 150 lb. driver. An increase in weight may call for higher pressure to keep the proper shape on the tire.
Air loss over time and temperature variation from winter lows to summer peaks guarantee that tires not checked periodically will run at low pressures or high pressures. Use of nitrogen can counteract this effect. This results in reduced road gripping capability and premature wear on the tires, reducing the effectiveness and life of the tire. Check for the correct air pressure once a month or every couple of fueling stops.
* Checking fluid levels
Fluid level is very important in all vehicles as low or even overfilled fluids can cause malfunctions or even damage. Recommended fluid levels can be found on the sides of fluid reseviors (if Equipped) or can be checked by means of a dipstick. certain fluid levels can only be checked under certain criteria whether it be with the engine running or off, hot or cold depending on the system. always check levels on a flat level surface as an inclination will give erroneous level readings. Each system uses a different fluid type. most systems require fluids for lubricaion others require fluid for creating pressure to perform a task. all underhood fluids that perform a task are formulated similarly across all vehicle manufactureres but may vary with certain models always check an owners manual or underhood stickers before adding. some vehicles require a special fluid
The brake fluid reservoir should not be opened unless you are performing repairs. Brake fluid is hygrophobic and will absorb water from the air, which degrades heat tolerance and performance. Current standards hold that the fluid level should be visible without opening. Low or missing fluid will trigger the float sensor and light up the brake warning light. If you are low on brake fluid, check your brake pads for wear.
* Checking the oil.
Most cars and truck have an easily accessible dipstick to make routine checking of the oil easy. When you fill up with fuel either ask the station attendent or check the oil yourself. Extract the dipstick. Wipe it down clean with a clean rag or paper towel. Reinsert the dipstick all the way. Extract it again and look for marks near its end that are labeled as being a full zone, needing a quart, or add more than a quart.
* Adding oil when necessary.
When adding oil be sure to locate the proper spout to put the oil in. Many cars and trucks have places to add transmission fluid, brake fluid, windshield cleaners, radiator coolant in the same engine compartment. It will thoroughly mess things up to be putting motor oil in the improper place!. Check the owner's manual or look for specific labeling on the spout plug. Oil is typically but not always added at or near the top of the engine block.
* Changing the oil.
* Checking the transmission fluid in automatic transmissions.
* Changing brake pads on disc brakes.
Replacing your own pads is never recommended due to liability.
Worn pads can be visible through the caliper, usually after the tires are removed. Use a clamp to compress the pads toward the caliper to push the piston out of the way. Open the bleeder nut to relieve pressure and try not to force fluid up the brake line. Push the piston to the bottom. Remove the slider pins to pull the caliper away. Do not disconnect the brake line or let the caliper fall and pull on the line. Keep the thin metal clips and plates, they reduce noise. Reassemble and fill brake fluid.
* Lights
It is appropriate every couple of months to check that all your lights are working and in the case of headlights aimed properly. To check direction of headlights on low and high beam park square in front of the side of a building or back of a garage and toggle the headlights to get an idea of where the high and low beams are aimed. The low beam should be aimed down a bit and slightly away from on coming drivers. The high beams are higher to penetrate down the road and also slightly off center to reduce visibility problems for oncoming drivers. It is important and useful to clean dirt and grime off of lights even if the car undergoes no other periodic washing. This enhances the effectiveness of the lights.
* Washing and Waxing Exterior
Routine washing can substantially reduce corrosion problems while waxing can extend the lifetime of the paint on the car exterior. Some cars now have special exterior coatings on top of the paint so checking the owner's manual for suggested washing practices is appropriate.

## Repairs as Necessary

Repairs as necessary usually occur when an automobile no longer functions safely or at all. It could involve something easily done for yourself such as changing a flat tire using a spare from your trunk or something much more demanding such as overhauling or repairing a transmission.

## Equipping a Home Shop for Automobile Maintenance

The basic tools needed for home maintenance is actually quite simple. Most small repairs and maintenance can be done with either a metric or standard set of sockets and wrenches respectively. A ratchet can make repairs a lot faster. Both flat head and Phillips screw drivers could be needed. A small tire gauge gives a quick, inexpensive, and easy way to determine of your tires have enough pressure increasing fuel economy.

## Diagnostics

All machines are prone to failure. In vehicle maintenance and repair, it is necessary to properly diagnose the cause of failure so that one does not needlessly replace or worsen vehicle components. Mechanics use deductive reasoning to locate the source of problems.
For example, if the vehicle does not start, details about the failure will point the mechanic in the direction of the source of the problem. The vehicle could wind up and not turn over, indicating that the source of the problem is fuel, as an electrical problem can be ruled out. Then it is a simple matter of tracing the flow of fuel. If it did not crank, then it would be electrical, and one would merely trace the flow of electricity.
The first step in diagnostics is deducing which system contains the fault. In the above example, we were deducing if it was either the fuel or electrical system. Once we can conclude the system that is at fault, we have to trace the system starting at its origin (eg fuel tank, batteries) and follow it to the at fault component (eg starter motor.) The exception to this rule however is if the component is relatively easy to access, easy to replace, and cheap to replace, it maybe favorable to view this earlier on.
For example if a headlight is out, it maybe unnecessary to start at the batteries. A simple check at the lamp or fuse box may suffice, as both of these products are cheap and easy to replace. It also should be noted that these items were made to be easily replaced due to their short lifespans (compared to the rest of the vehicle.)