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Basic Mechanics Manual 📖 Learn Automotive Mechanics Easy

Enter the fascinating world of mechanics with our Basic Mechanics Manual, an essential guide that you can read and download in PDF.

This manual covers fundamental topics such as engine operation, braking systems, transmission, and preventive maintenance, providing solid knowledge for all automotive enthusiasts.

Discover the secrets of mechanics and enhance your skills!

Table of Contents

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Read Basic Mechanics Manual for Beginners

Basic Mechanics Manual for Beginners
Basic Mechanics Manual for Beginners

We won't tell you "do it yourself" on the contrary, that's what mechanics and technicians are for. car workshop manuals, but it is necessary to clearly know what the problems are and their solutions so as not to pay too much and be scammed.

What to do if the car doesn't work?

There are several reasons why a vehicle does not start, but the main causes of this problem are due to the electrical system.

Broken or damaged car does not start - Basic Mechanics Manual
Broken or damaged car does not start – Basic Mechanics Manual

Check if the alternator starts and runs.

Si the alternator does not turn on We must observe if any light turns on on the dashboard or if any other device that uses the battery works.

Check if the accumulator or battery works
Check if the accumulator or battery works
  • Then it is a battery or accumulator problem and we must check that the terminals are tight and free of sulfate.
  • Otherwise we disconnect them, wash with water and reconnect.
  • If the problem still exists, you must remove the battery and take it to a service center to have it charged and corrected.
  • With the battery charged it still does not turn on so you have to locate the main fuse and if it is blown change it, it is in the engine compartment.
  • In modern vehicles, be careful not to connect the battery with reverse polarity, this will blow the main fuse or damage the battery. vehicle computer.
  • If the electrical accessories work, but the alternator does not turn on, then it needs to be repaired.
Check Alternator
Test and Verify if the Alternator turns on.

Most common car faults

The most common faults are "Bendix" (the device that connects and disconnects the alternator pinion with the car engine), You also have to check the bushings, carbons or the armature that go inside the alternator and the work is simple for any automotive electric.

Every time we start we are wearing out the parts of the alternator, particularly the carbons, which is a normal failure due to use.

In either of the two previous cases, if the car has a manual gearbox, it can be easily started by pushing it.

Push car with manual transmission to start.
Push car with manual transmission to start.
  • Turn the ignition key to “On” (let the warning lights come on), put it in second gear and depress the clutch fully.
  • You start pushing until the car takes flight and you release the clutch with a snap while you step on the accelerator.
  • As soon as the engine starts, you obviously have to press the clutch again to prevent the car from shooting forward.

Failures of cars with automatic transmission

Air shipments are the most efficient if you need your cargo or documents to arrive quickly and securely. cars with automatic transmission They do not start when pushed and do not even have to be towed in some cases.

If the alternator works, but the engine won't start, the problem is one of the two lines that make the engine run: The fuel line or the spark line.

Engine Carburetor
Engine Carburetor

The fuel line is made up of the pipes that leave the gasoline tank, pass through filters, reach the petrol pump, and from there they go to the injection body or the carburetor, depending on whether the engine is injected or carbureted.

Failures in cars with electronic injection

In the injection engines It is not easy to know if fuel is arriving because it is at high pressure. The usual thing is to loosen the main nut that comes from the fuel pump to the injection body a little and see if fuel drips.

Failures in cars with carburetor

In a carbureted car it is much simpler: you open the fuel tank cover. air filter It goes on top of the carburetor and you look through the carburetor tube to see if fuel enters when accelerating.

Typical fuel line failures are: clogged filters, damaged pump (some pumps are submerged in the gasoline tank, in which case repair and replacement are expensive), carburetor or injection body clogged by some debris.

In a pinch you can pour gasoline directly through the mouth of the carburetor, of course only a little because with too much the engine drowns and it would not start with anything for a long time.

Repairing Engine Carburetor - Basic Mechanics Manual
Repairing Engine Carburetor – Basic Mechanics Manual

Generally, on injected cars there is nothing that someone who is amateur or without the proper tools can fix.

In carbureted cars you simply have to locate what is clogged and clean or change (generally filters).

The spark line goes from the battery to the coil, then to the distributor, which is the device from which the sparks come out. Spark plug wires and finally to the wires that go to the spark plugs.

Common faults in more modern cars

In modern cars the coil usually goes inside the distributor. The spark line is the easiest to test because it is enough to lift a spark plug wire at a certain distance from the head of the spark plug, start it and see if the spark jumps. It can also be tested by bringing the spark plug wire closer to the iron mass. of the engine and see if there is a spark.

If there is no spark, it is possible that there is no current reaching the coil (this must be measured or tested with a 12v light bulb), that the ignition module or the coil is damaged. These are the most common causes.

In older cars that use platinums To excite the coil, the point adjustment may be too open.

How to inspect a used car

How to Inspect a Used Car - Basic Mechanics Manual
How to Inspect a Used Car – Basic Mechanics Manual

Another common problem for those who do not know mechanics is how to inspect a used car or an engine that they want to buy.

Turn on Auto
Turn on Auto

The first thing is to observe if the engine runs smoothly at idle (that is, in neutral), that gives a first impression of the health of the engine, then there is nothing better than going up a very steep hill to see its strength; The lower the gear the less power the engine has, of course this depends on its size, as some small engines may even need second gear to go up.

On a flat and straight road, let go of the steering wheel and see if the car pulls to any side. In that case, the front axle could be crooked (serious failure) or simply misaligned or the tires inflated unevenly.

Also let go of the steering wheel and brake to see if it pulls to one side, which would indicate that you are braking unevenly.

Detect fault due to car exhaust

Check the exhaust pipe for excess carbon, accelerate and see if blue smoke comes out, accelerate violently and release to see what happens at idle.

Check Spark Plugs
Check Spark Plugs

The best indication of the health of the engine is to take out the spark plugs and look at them, this shows an x-ray of what is happening inside: if it burns well, if oil enters, etc.

Turn in a closed circle to see if the bearings (the wheel joints in the front axle) rattle, with the car stopped push the corners down, if it bounces the shock absorbers are bad.

With the right wheels in the air (raised with a hydraulic jack), move them to see if they have too much lateral play (bad ball joints).

Failures observing the tires

Observe the tires if they have uneven wear or wear to one side, it is a bad sign.

A freshly washed engine or chassis is a bad sign, it turns out that the owner wants to hide an oil leak. Oil leaks from the valve cover, distributor or crankcase gasket are normal in used cars and if they do not leave a pool it is not a problem.

Engine with oil leak
Engine with oil leak

When the car that has been left idle overnight leaves a pool of oil. It's a good idea to look at the ground where you usually park your car.

If you have doubts about the strength of the car, you can measure the compression; it is not so important that the values ​​are high but rather even.

If one cylinder has much less compression than the others, the vehicle is ready for an expensive tune-up.

The condition of the seats is a good indicator of how the car has been used, original or old upholstery in good condition reveals a careful owner, new upholstery or covers on very torn upholstery show that the owner was not so concerned.

Check all the dashboard lights, heating, etc. that work correctly.

Parts of an engine

From top to bottom we have the valve cover, cylinder head, block, sump, on the one hand exhaust manifold  normally towards the radiator) and on the other the intake manifold with the carburetor or the injection body as appropriate.

Parts of a Car Engine - Basic Mechanics Manual
Parts of a Car Engine – Basic Mechanics Manual

Also on the side are the spark plugs whose cables go to the distributor. Further down the side is the starter motor and alternator.

Inside, on the cylinder head we have the camshaft, the valves with their springs, guides and checkpoints, the threads of the spark plugs.

In the block and inside the cylinders we have the assembly of the pistons with its 3 or 4 rings each and Rods connected to crankshaft. At the end of the crankshaft it is connected to the flywheel, which is a large, balanced, toothed iron disc.

Then comes the clutch system with the disc and the press and the gearbox.

Carbureted cars and injected cars

Due to anti-pollution regulations since the 90s, practically all cars are injected, older cars use carburetors.

The carburetor is basically a tube through which the air enters, next to it it has a tank with a float similar to the toilet system where the fuel is temporarily stored little by little and an area where the air and fuel mix, this mixture is regulated By two screws that have a small hole in the middle, the "nozzles", the carburetor has a "high nozzle" and a "low nozzle" that serve to regulate the air and fuel mixture: the tighter it is, the leaner it is. the mixture (that is, more air) and vice versa.

carburete a car It consists of adjusting these screws so that it maintains its idle speed without turning off when it is in neutral and at the same time responds quickly to the accelerator (which is simply a tab that regulates the amount of fuel we inject into the system.

Engines with carburetors are called "aspirated" because the mixture enters the cylinders through the vacuum produced by the piston when it descends, unlike "injected" engines where the mixture is introduced under pressure into the pistons.

Air shipments are the most efficient if you need your cargo or documents to arrive quickly and securely. injection cars They have a more complicated system and with fewer possibilities of getting involved because they consist of a computer that regulates the injectors, an injection body and one or more injectors (it can be a single "single-point injection" or one for each "multipoint" cylinder).

Basic Mechanics Manual - Singlepoint and Multipoint Motors
Basic Mechanics Manual – Singlepoint and Multipoint Motors

Knowing the type of injection is easy: if it has a single fuel inlet port similar to a carburetor, it is single point and if it has one inlet per cylinder it is multipoint.

How does an engine work?

Engine Piston
Engine Piston

The piston in this case is what goes on top, it has a pin that connects it to a connecting rod and this is at the same time connected to the crankshaft, which is the large piece at the bottom with a counterweight. In other words, vertical movement is converted into circular movement.

But they will wonder And why does the piston go up and down?Well, all this goes inside a closed chamber called a cylinder, in that chamber a mixture of air and gasoline is injected that is compressed when the piston runs up and is ignited by a spark produced by the spark plug, this causes an explosion that pushes the piston down with great force which makes the crankshaft rotate, then the crankshaft counterweight makes the piston rise and the whole thing repeats itself.

An engine will have more power the larger the chamber and the more cylinders it has. There are engines from 1 to 16 cylinders. The most popular today is the 4-cylinder in-line, but there are also 6 or 8 cylinders arranged in a "v" for the most powerful engines.

One or two cylinder engines are typically used in motorcycles, chain saws, and very small engines.

Below we show you a more descriptive and detailed video of how an engine works.

The main systems of an engine

Engines have several systems that can be understood separately, each with its specific function, we already briefly saw the two main ones: the spark system and the fuel system, other systems are:

Refrigeration system

It circulates coolant (or water in the worst case) through the engine to cool it as soon as it reaches a certain temperature.

The engine block has hollow ducts through which water passes. This system consists of a radiator, electric fan, electro switch, water hoses, Water Pump, and thermostat.

When the engine overheats, one of these has failed. Typical failures of this system are: broken or damaged water pump, clogged radiator, electric fan with burned out motor, bad electric switch (the one that turns the electric fan on or off, it is a bulb that is screwed into the radiator and has a cable to the fan), broken water hoses or bad thermostat.

Elements that make up a Car Engine Cooling System - Basic Mechanics Manual
Elements that make up a Car Engine Cooling System – Basic Mechanics Manual

The engine should not run too cold (it wears out) or too hot (some component may deform, melt or seize, which is commonly called "cast engine").

So that it does not work too cold, there is a thermostat that cuts off the flow of water until it reaches its optimal temperature.

An engine can run without a thermostat (bad mechanics sometimes remove it) but it will not run well and will have premature wear.

The water then circulates through the engine once the thermostat turns on, driven by the water pump, it heats up in the block, then enters the radiator where it passes through tubes with copper fins that cool the water helped by the fan and the The wind that enters as the car moves forward, re-enters after cooling, that is, it extracts heat from the block and cools it to its operating temperature.

Engine Overheating

Also known as overheating, it is one of the most scandalous failures for those who do not understand mechanics, however it is normally much less serious than what ordinary people imagine or what mechanics imply.

About Car Engine Overheating
About Car Engine Overheating

If the temperature rises a lot, it is best to stop the car and check what is happening. In this case it is very dangerous to remove the radiator cover because the boiling water will jump directly into your face. You have to wait for the water temperature to drop a little, wrap your hand in a large cloth and only turn the cover a quarter turn. of the radiator to relieve pressure.

Once all the steam has come out we can remove the lid. There are two causes of overheating: either the water is not circulating or the water is falling somewhere.

Considerations to take regarding engine overheating

A breakage of the alternator belt (it is very common) that also activates the water pump causes the water to stop circulating and the engine to heat up, another failure that has the same effect is when the thermostat gets stuck, it could also happen that the electric fan does not work when it should, a last possibility is that the radiator has its ducts clogged.

If the car has not lost coolant (or water) then it is the previous failures, if there is coolant loss the causes could be breaks in the water pump, hoses or radiator, the latter can be fixed quite well with epoxy putty.

The worst failure that can cause overheating is a rupture of the cylinder head gasket, in this case the engine loses power, the oil level rises and shows bubbles and a milky color (mixed with water) and sometimes comes out of the exhaust pipe. a water vapor cannon.

Below you will be able to learn in more detail what the cooling system of an engine is like.

This failure is fixed in a workshop where they can lift the cylinder head, which is a complicated job and must be done by someone who knows what they are doing for reasons that we will explain later.

In any case, if the car is stopped and slowly taken to a workshop, this normally does not cause further damage to the engine.

A little-known effect of overheating is that it ruins the properties of the lubricating oil, so after prolonged overheating it is a good idea to change the oil.

Oil lubrication system

The oil circuit circulates through all moving parts of the engine. The oil collects in the sump which is the bucket that is under the engine, submerged in it is the oil pump that drives it upwards passing through the oil filter, the oil ducts of the block until it reaches the camshaft, after watering and lubricating the shaft of cams, the oil goes down through the oil rings lubricating the pistons and continues downwards lubricating all the moving joints of the connecting rods, connecting rod seats, crankshaft, etc.

After doing the entire circuit, the crankcase falls back and starts the whole process again. Some vehicles have an oil radiator that cools it within its circulation.

Lubrication system failures

They normally have serious consequences and can be: rupture of the crankcase or oil pipes (so the oil falls out), a broken oil pump or clogged pipes, so the oil does not circulate.

Engine Lubrication System Failure
Engine Lubrication System Failure

If the circuit operates without oil or the oil does not circulate, excessive heating and wear may occur when metal comes into contact with metal, and even moving parts may become deformed and jam ("blown" engine).

It can also happen that water enters the oil through the cylinder head gasket, when this occurs the car loses power because water enters the pistons, a jet of water vapor comes out of the exhaust, the oil level rises and the oil takes on a coffee-au-lait color, the water in the radiator fills with foam.

In cars with a lot of use, natural wear occurs in the cylinders, which enlarge with friction and are no longer airtight, then the lubrication oil begins to enter the cylinders and the car emits blue smoke through the exhaust pipe (not to be confused with white smoke which, in moderate quantities, is water vapor and indicates perfect combustion).

Blue car smoking
Blue car smoking

In this case it is said that the car is burning oil, the oil is used up quickly and the cylinders stop
work because the spark plugs get wet with oil and do not light, the car loses power and runs only with three or fewer cylinders.

Car Engine Tuning

To know if this is happening is very simple: just take out the spark plugs and check if one or more are wet with oil, this is a good indicator but not decisive because the oil could also be passing through the top of the spark plugs. valve sealsBy removing the cylinder head you can see the condition of the cylinders with the naked eye.

The use of poor quality tap or distilled water is the most common cause of irreparable engine deterioration.

Oil Change

Modern cylinder heads, which are made of aluminum, corrode and split with poor quality water, the same goes for the block. It is best to use Preston "prepared mix" or some antifreeze of similar characteristics instead of water.

Basic Mechanics Manual - Changing Car Oil
Basic Mechanics Manual – Car Oil Change

The oil and its filter should be changed regularly. recommended by the manufacturer, normally the recommendation is each 10.000-15.000 Km or every 6 months whichever comes first.

There is no topic more surrounded by deception, urban myths and marketing than this, since many stores where they sell oils make a living from this activity and recommend extremely short changes every 3.000km or 3 months, or more expensive brands.

Regarding oil brands, there is no independent institute that tests them, so everything they say comes directly from their marketing departments and there is no reason to believe it.

Types of Car Oil
Types of Car Oil

However, there is the API standard (from the American Petroleum Institute) that sets minimum specifications by type of use, it is a good guide.

Automotive oil specifications

Oils have two main specifications: SAE which indicates the viscosity at different temperatures and API which is a kind of measure of oil quality.

The manufacturer recommends the SAE but normally this can be changed without problems. The first number SAE is viscosity at low temperatures and the second at high temperatures, that is, a viscosity index of 20-40 indicates a viscosity degree of 20 when cold and 40 when hot.

Among the myths promoted by oil sellers There is a famous one that says that oil of a certain quality or brand turns into mud after a certain time, which clogs the passages and causes damage to the engine.

This myth is a lie, no oil turns into mud, what actually happens is that if the vehicle has a faulty ignition it produces a lot of carbon, which ends up being removed by the oil, that is, the mud is formed in the same way with any oil if the mixture is burning poorly.

Types of car oils

There are mineral oils, synthetic and mixed (mineral with synthetic) the latter are a good option but making the changes in due time, mineral oils are cheaper and give exactly the same result.

Changing a Car Oil Filter

You always have to change the filter, this is more important than the oil change itself.

If we change the oil and leave the old filter, when the new oil passes through the dirty filter it will immediately get dirty.

Oils can be recycled (waste used oil), they are cheaper, more ecological and do not lose any of the properties of a first-use oil, in fact the use of recycled oil is recommended by the API.

If the oil turns black or thick after a short time of use, it is not a problem with the quality of the oil (as many oil store owners would have you believe) but with defective combustion that is producing a lot of carbon.

Use oil filters A good brand can be as beneficial for the engine as using antifreeze instead of water, but we must not forget that the problem in an engine is generally combustion, not oil.

Electrical system of a car

Basic Mechanics Manual - Car Electrical System
Basic Mechanics Manual – Electrical System of a Car

Cars come with an electrical system that has mainly three functions:

1. Start the car with the starter motor
2. Power the spark system
3. Provide electrical power to the lights, horn and various accessories

The electricity of the car with the engine off comes from the battery and with the engine on from the alternator, that is, the rotation of the engine produces electricity ( You can also consult the Complete Manual Basic Electricity Beginners ) enough for all systems even if the battery is completely discharged (that's why many cars work by pushing them).

On the other hand, while the engine rotates, the generator is constantly recharging the battery.

The battery discharges only when starting the car and it discharges quite a bit because the force necessary to turn the engine off is not small or when
We are listening to music or something with the engine off.

The Automotive Battery or Accumulator

It is a electric charge accumulator, they are normally 12 volts and have 6 "glasses" each of which generates 2 volts. Inside it has lead plates immersed in a mixture of water and sulfuric acid.

Batteries have different capacities depending on the size of the vehicle or the number of electrical accessories it has.

Capacity has more to do with engine size than anything: Large motors are heavier to spin and require larger batteries.

Basic Mechanics Manual - Batteries or Accumulators for cars
Basic Mechanics Manual – Batteries or Accumulators for cars

Typical capacities are 40, 60 and 90 Amperes/hour. If we put a larger capacity battery in a small car, nothing bad happens, on the contrary it is better to always have one a little larger than the recommended one.

When buying a battery they can sell us an instant one that is already charged and ready to use or a dry one, which has to be filled with liquids, this last option is much better because instant ones have a life cycle and they can easily sell us one. It's already expired, there's no way to know, it's just that it will last much less.

Tips to consider charging batteries

Due to their capacity, batteries can produce large sparks in the event of a short circuit (bringing the positive and negative together), so they must be treated with care when connecting and disconnecting as they also emit flammable gases.

The battery is tested with a densimeter, they normally do it for free in the service stores, if the hydrometer floats in the green or yellow part, the battery is OK, if the battery discharges it may be that it is bad or that the system that recharges it (alternator, etc.) is failing, the service stores do the load tests for free.

A charged battery should have approximately 13 volts and with the engine running it should receive about 14.5 volts that should not drop when the lights are turned on or rise when accelerating.

Automotive Fuse Boxes

Cars generally come with a fuse box inside for accessories, lights, etc. and another in the engine case for the main fuses.

Automotive Fuse Box - Basic Mechanics Manual
Automotive Fuse Box – Basic Mechanics Manual

The fuses are sure to blow when there is a short circuit, so it is the first thing to check in case of an electrical problem, they can be easily tested by removing them and making a bridge with a screwdriver or any conductor: if the device works with the bridge means that the fuse has burned out, if when you replace it with another one it burns again it means that there is a short circuit.

The Automotive Alternator

Automotive Alternator
Automotive Alternator

It is a device that generates current when the engine is rotating, it turns thanks to a belt that is normally also used to turn the water pump, when this belt breaks or loosens (it has a nut to tighten it) the alternator stops to load.

Other common problems with the alternator are that it does not receive field voltage from the battery (blown fuse, bad connection, etc.), that it has worn carbons, a burnt diode plate or a burnt armature.

The regulating box

In most modern cars it is built into the alternator and it is a chip, there is nothing to do.

Voltage Regulator Box for Cars
Voltage Regulator Box for Cars

In older cars it is a separate box with relays (electro magnet switches), its function is to keep the voltage delivered by the alternator constant at about 14 volts.

When the engine accelerates the alternator produces a lot of voltage (17 or 18 volts), the regulator box must cut it to 14 volts, when we turn on the lights or accessories the alternator voltage drops because more current is consumed, the regulator box must then allow more to pass. current so that it remains at 14 v.

A bad regulator box is noticeable because the lights go up when accelerating, normally after a while of driving like this the armature or the diode plate of the alternator burns out.

the starter

This was explained at the beginning of this Basic Mechanics Manual for Beginners, is an electric motor with a pinion that engages and disengages from the engine flywheel (popularly called "the Bendix"), it is a quite powerful motor and that consumes a lot of current, the Typical faults are: Burnt Bendix, worn carbons, burnt armature, bushing failures.

When the engine does not want to start and we start it many times in a row and for a very long time, the starting engine suffers enormous wear and overheating that eventually produces any of these failures.

Car lights and accessories

The lights and accessories have a complicated circuit with large bundles of cables, generally passing through a fuse box, switches and relays.

The most common accessories are: wiper, glass heater, radio, interior lights, cigarette lighter, dashboard lights, etc.

Braking system

There are basically two types of brakes: disc and drum, disc brakes are more efficient and most cars have disc brakes at the front and drum brakes on the rear wheels. Why? simply because the front wheels are the ones that do most of the braking effort.

Car Brake System
Car Brake System

More expensive cars have four-wheel disc brakes although this is only significant at very high speeds, while older cars have four-wheel drum brakes (for example VW sedan or Citroen 2CV).

Disc Brakes for Cars
Disc Brakes for Cars

Air shipments are the most efficient if you need your cargo or documents to arrive quickly and securely. disc brakes They work similarly to brakes of a bicycle: Before the wheel there is a hardened steel disc that has two pads that, when the disc is pressed, brake the wheel as shown in the figure.
The disc rotates with the wheel and inside the black apparatus (called Caliper) there are the pads that squeeze it and make it brake.

The disc in the image is high performance because it has two separate plates and holes for cooling (as you might imagine, when you squeeze something that rotates, both the disc and the pads or pads get very hot).

A common brake failure is that stones or dirt get between the pad or lining and the disc. When the pad presses the brake, the disc gets scratched. New cars have very smooth discs while older cars get scratches. .

Tips for diagnosing brake failures

Generally the brake workshops ofrecen rectify brake discs very scratched, putting them on a lathe-like machine that peels them and leaves them smooth, in my opinion this is not a good idea because the only effect is to weaken the disc.

A disc with stripes brakes practically as well as a smooth one and the pads adapt and wear out just like the stripes. It is only advisable to rectify a disc if it is crooked, and this must be clearly shown.

Useless rectifications are a typical trick of brake workshops. When a wheel squeaks or rattles, it is because dirt has gotten into the pads or because the pad is completely worn out and is touching iron to iron, the changing pads or pads It's not difficult as long as you've seen it many times before.
how to do it, jumping into learning blindly is not recommended under any circumstances.

Air shipments are the most efficient if you need your cargo or documents to arrive quickly and securely. drum brakes They have a drum on the wheel that rotates, that is, the drum moves but the center remains fixed, in this center the system is mounted with piston pads, springs and regulations as shown in the figure.

Automotive Drum Brake - Basic Mechanics Manual
Automotive Drum Brake – Basic Mechanics Manual

The cylinder has two pistons that come out and press the pads (brake band) on the drum, stopping its rotation.

The brake circuit

Cars use a work hydraulic with a pump and high pressure pipes to push the pads onto the disc (front) or the pistons onto the pads (rear).

For safety reasons there are two independent circuits in "X", one for the right front wheel and the left rear wheel and vice versa, so if one circuit fails (that is, if it loses fluid) the other remains in operation because they are not connected.

Brake Circuit for Cars - Basic Mechanics Manual
Brake Circuit for Cars – Basic Mechanics Manual

Most modern cars also have a “brake servo,” which is nothing more than an additional pump powered by the engine, which helps provide more pressure than we can exert with our foot.

El brake circuit then it consists of discs, caliper, pads or linings (front wheels), drums, cylinder, shoe, lining and various cachureos (rear wheels), two independent circuits of pressure pipes, the servo and the brake pump with its two separate chambers and a tank for brake fluid.

Apart from the wear of the components that go into the wheels (pads and linings), system failures can be: loss of brake fluid due to a joint in the pipes or wheels, failure of the rubber of the pump or cylinders, or internal scratches in the metal of the cylinders or pump, this last failure is the most expensive since the entire parts must be replaced.

Brake fluid

Depending on the car, the fluid it requires, the fluid specification is DOT, which is the point at which the fluid begins to boil, losing its efficiency (for example, DOT 3 boils at 215 degrees without humidity and 140 degrees with humidity).

Brake Fluid for Cars - Basic Mechanics Manual
Brake Fluid for Cars

Most normal cars use DOT 3 or higher, for street use I suppose DOT3 is more than enough, however in vehicles that have computer-assisted anti-lock brakes ABS Manufacturers recommend DOT 4 or higher.

Over time and with use, brake fluid forms water, which loses its effectiveness and corrodes the cylinders and the pump. It is advisable to change it every couple of years or so.

The key to not spoiling the circuit is to always use impeccable liquid, that is, from the sealed and recently opened jar.

Any tiny dirt gets into the cylinders and scratches them. The liquid is very corrosive to car paint and very good for loosening or loosening nuts.

ABS brakes


They are a special computer-controlled anti-lock braking system, they have sensors y actuators in the discs that when they detect that the brake begins to lock (which happens for example in a harsh braking on a slippery surface) control of the brakes is taken over by the computer, which repeatedly presses and releases them.

Anti-Lock System ABS Brakes
Anti-Lock System ABS Brakes

This allows braking with less skidding and shifting, but increases with a lot of electronic devices that require maintenance and eventually break down, as happens with many other technological improvements.

In addition, the service of parts and spare parts is expensive and there is very little that one can fix by oneself.

Transmission or gearbox system

La gearbox It serves to translate the engine's power into speed or force as needed. For example, to get a car from immobility or to climb a steep hill requires a lot of strength and little speed, while to run on a flat road you need almost no strength and a lot of speed.

This translates at the same time into the revolutions per minute (RPM) how an engine works: when we go in low gears (first, second) the engine makes force and it goes at high revolutions (typically between 2500 and 4000 rpm), when we go in high gears (third, fourth, fifth) the engine goes at lower revolutions and has little power: everything translates into speed.

As each revolution of the engine consumes fuel, while we go at a higher speed and lower rpm, driving will be more economical. A car designed to be very economical reaches 100 Kph at about 1500 rpm or less.

Manual Transmission or Manual Gearbox

Manual Transmission or Manual Gearbox
Manual Transmission or Manual Gearbox

A car has an engine for its operation and movement. This mechanism produces a movement and force that must be transmitted to the wheels (be they the front or rear) for movement to occur. Well, for that another mechanical system called gearbox.

The gearbox is an element that is coupled to the engine. The manual gearbox It serves to manage the engine revolutions and produce the movement of the vehicle.

The flywheel belongs to the engine; The disk is attached to it. clutch or clutch and they serve to smooth and cushion the coupling of the motor with the gearbox when inserting them.

Manual Transmission Features

La gearbox It's formed by gears of different size and synchronizers. When you move the lever to make a change, you are sliding a synchronizer from a small gear to a larger one or vice versa and the movement of the vehicle depends on this.

The reason why it is necessary to make changes is that the engine begins to spin, keeping the number of revolutions stable when you accelerate it, and if the revolutions increase, the engine feels stronger and that is where the box through the differentials , sends the force to the wheels that have traction.

We recommend you watch the following video that is Basic Mechanics Manual for Beginners will explain the more detailed operation of the Manual gearbox.

Nowadays, manual gearboxes use hydraulic aids to make handling easier for the driver. In addition, they are manufactured with a greater number of speeds to improve fuel efficiency by taking advantage of the engine's revolutions and force in a more specific way.

Automatic Transmission or Automatic Gearbox

Automatic Car Transmission
Automatic Car Transmission

Your engine connects to your transmission in a place called the crankcase or converter box. On vehicles equipped with an automatic transmission, this box contains a torque converter instead of the clutch on manual vehicles.

The torque converter is a hydraulic coupler whose job is to connect your engine to your transmission, thereby driving your wheels.

Characteristics of the Automatic Transmission Box

The transmission contains planetary gears that are responsible for providing different gear ratios.

To get a better idea of ​​how the entire automatic transmission system works, let's take a look at the torque converter and planetary gears and their function which is explained in more detail in the following video.

Well, we hope that this Basic Mechanics Manual for Beginners It has been useful and that you now know a little more to solve common faults in your car.

If you have a little more knowledge about Car Mechanics, we recommend that you look for the specific manual for the make and model of the car in the following links.