Mechanism and adjustment of parking brake (side brake)

Mechanism and adjustment of parking brake (side brake)

A car brake, also called a braking device, is a device that stops or slows down driving. Roughly speaking, there are three types: foot brake, engine brake, and parking brake (side brake). This article mainly describes the parking brake to keep the tires stationary when parking.

Car brake

The car’s braking system includes a foot brake used while driving, an engine brake that uses the rotational resistance of the engine instead of an independent braking device to reduce output, and a parking brake (side) used when parking. There is a brake). First, let’s briefly explain the foot brake and engine brake used when driving.

Foot brake

The foot brake is a brake that is applied by stepping on the pedal, and is the main brake that uses hydraulic pressure (brake fluid) and is used from running to stopping. There are two types of foot brakes, disc type and drum type. The disc type tightens the rotor (disk) attached to the axle, and the drum type presses the brake shoe against the cylindrical drum to apply braking, and the vehicle weight of 1 to 2 tons runs at a speed of 50 to 100 km / h. It exerts a very large braking force to stop what is being done.

Engine brake

The engine brake is a brake that loosens the accelerator while driving, and when the supply of gasoline to the engine is stopped, the resistance such as the friction of the piston or the brake that drops to a gear lower than the speed and decelerates with the resistance of the gear. is. It can prevent fading and vapor lock caused by overuse of the foot brake, mainly on long downhill slopes.

What is a parking brake (side brake)?

The parking brake (side brake) is mainly used to keep the vehicle stationary when the vehicle is stopped. It is also known as the side brake because it is next to the driver’s seat.
Most parking brakes are mechanical brakes in which the wire is pulled when the lever is pulled, and the tension acts to link the brake mechanism, tightening the brake pads on the two rear wheels. When the engine is running with the parking brake applied, the brake warning light on the instrument panel lights red. Since it is an auxiliary to maintain the state of the stopped car, the braking force is considerably lower than that of the foot brake.

Even if you inadvertently start running with the parking brake applied, such as when you are in a hurry, you will not notice it for a while, and after running to some extent, the speed will not increase as you think. I’m sure there are some people who have the experience of thinking that, or finally noticing the lighting of the brake warning light, and releasing it in a hurry. In this way, it has only a braking force of “dragging” while running with it applied.

Types of parking brakes (side brakes)

There are various types of parking brakes (side brakes) depending on their form.

Wand type side brake

Until about half a century ago, when the front row bench seats of automobiles were the standard, pull the stick-shaped T-shaped lever at the bottom of the instrument panel under the handle toward you, and then twist it a little and then push it back to release it. Parking brakes called “stick type” were common.
Currently, only one commercial van is used for domestic vehicles.

Lever type side brake

The side brake is a method that has become popular since the front row was separated from the bench seat to the left and right, creating a space for arranging floor missions. Pull up the lever lying down on the floor beside the driver’s seat (on the left side of the driver in a right-hand drive car), and press the notch (button) at the tip to release it. This type is the most common passenger car, and I think there are many people who are familiar with it. As an aside, in rally competitions, it is also useful as a necessity for driving techniques to change the direction and posture of the car.
Lever-type side brakes require a space for wires to pass through the floor inside the car, which hinders walk-through of minivans and restricts interior design, so they are on the decline.

Foot-operated parking brake

This equipment is limited to AT cars. There is a foot-operated pedal at the position of the clutch pedal of the MT car, and the brake is applied by depressing this. The advantage of the foot-operated parking brake is that you can use your leg strength to step on the pedal, so even people with weak strength, such as women and the elderly, can apply it firmly. There are two ways to release the parking brake. One is to depress the pedal again to release it, and the other is to pull up the lever on the center console next to the driver’s seat.

Electric (electronic) parking brake

This is a method that has been increasing rapidly in recent years. Just press a button (turn on the switch) and the power of the motor will apply the brakes with the same strength regardless of human power. Release is performed at the same time as the accelerator is depressed, and no release operation is required.
Since you will not forget to release it, it is also excellent in safety, and since you do not need to route the wire, there will be no tunnel on the floor, it will be easier to arrange seats, and the interior will be cleaner, so it will become more and more popular in the future. It seems to proceed.
It is expected to expand its functions through technological innovation, such as incorporating it into the system of automobiles, which are becoming more and more electrified, and linking it with controls that lead to autonomous driving. On the other hand, there are some precautions such as the fact that it cannot be released when the battery is dead.

Parking brake maintenance and adjustment

The foot brake is a hydraulic type, which requires a large amount of force to stop or decelerate a moving vehicle, and brakes all four wheels.
On the other hand, the parking brake is a device that assists the parked car from moving, and the two rear wheels are braked with wires.
Therefore, if you use it for a while, the wire will stretch, and the lever and pedal pull margin and stepping margin will loosen and become large, so you need to make regular adjustments such as rewinding the wire.

Often, when you switch driving from a man to a woman, you may get the impression that the parking brake is “hard” to release. Men inevitably pull up the lever strongly, but the handbrake pull (stepping) margin is made so that the brake will be applied firmly if it is pulled up to a certain level, and even if it is pulled harder than that, the braking force Does not increase. It is important to check the operating force (force required to pull the brake) and “notch number” (number of clicks when pulled) described in the instruction manual (in the text). If there is no description, it is in the item such as “Maintenance data”).

Is it unnecessary to apply the parking brake when parking an AT car?

You may hear the story that “AT cars do not need a parking brake when parking, so do not apply it.” This is a measure to prevent the wire from freezing in the morning and becoming difficult to release in cold regions, etc. (This is also the case with MT cars). In that case, it is a condition that the engine is always stopped in the P range and the wheel is fastened (with the gear in L or R in the MT car).
When the AT car puts the gear in the P range, the gear (parking lock pole) inside the transmission is engaged and locked. However, this is a structure that just hooks a metal claw on a small gear and stops it, and if a large force (for example, a car collision) is applied, the claw will break or come off, and the car will lose the stopping force. It will be. In such a case, if the frictional force of the parking brake is applied, it will not start to move so easily. Therefore, the basics are P range + parking brake. If you are in a situation where you cannot hang it, you should take all possible measures to prevent it from moving, such as putting a ring or a stone on the tire.

It’s easy to feel relieved after you park your car. Be careful not to apply the parking brake because it is a flat road, and apply the parking brake firmly.

Remember the role as an emergency brake

The parking brake can be used as an auxiliary brake while driving as well as an auxiliary brake when parking. It is a so-called slope start. If you stop on a slope such as a slope or railroad crossing, pull it when you start, and release it at the moment when the driving force of the accelerator is transmitted, you can start without worrying that a car will flow behind you.
It also plays the role of an emergency brake. As you learned at the driving school, if the foot brake does not work while driving, don’t panic and use the engine brake (switch to low gear in order while watching the tachometer) and the parking brake. The braking distance will be longer, but you can park the car. Keep it in mind in case of emergency.

How to adjust the handbrake cables

When it comes to cars, especially if they are a little dated, there are many problems and malfunctions and what is worse, they are often neglected, also putting the safety of the driver and other road users at risk. A common problem with old cars is certainly the handbrake that loosens, no longer able to lock the wheels. As we all know, the handbrake is that component necessary to safely park the vehicle, in fact, it must be pulled every time you get out of the car and this, locking the rear wheels through cables, immobilizes the vehicle, avoiding the risk that this moves. It is therefore evident that if the handbrake does not fulfill its function properly, the safety of all road users is put at risk, therefore, it is necessary to remedy this problem immediately by adjusting the cables.

Parking brake structure

The parking brake consists of a brake release button, rod (parking brake lever), ratchet lever (hook), ratchet (ratchet plate), parking brake switch, joint rod (parking brake rod), and equalizer.

When the parking brake is applied, the car will stop due to the ratchet mechanism. The ratchet lever is hooked on the ratchet plate and its position is held. When you press the release button, the ratchet plate is released, and the force of the return spring returns it to its original position.

In the case of a foot-operated parking brake, the car stops by stepping on the parking brake pedal with your foot. With the spread of automatic cars that do not use the left foot, the number of foot-operated vehicles has increased. The foot-operated parking brake has a ratchet plate fixed to the parking brake pedal, and the pole is provided on the vehicle body side. By stepping on the pedal, the ratchet and pole engage and the brakes are applied.

To release the parking brake, depress the parking brake pedal again to disengage the ratchet and return the pedal.

How to check the parking brake

The parking brake does not affect driving, but if something goes wrong, the car may start moving, such as when you park your car on a slope. Be sure to check it regularly.

If you use the parking brake for a long time, the brake wire may stretch. Also, if the force of the spring is weakened, the parking brake will not be completely released and it will be in a dragged state. Dragging is when the parking brake is not applied, but the brake is always applied. Be aware that dragging can lead to poor fuel economy and overheating of the brakes. If dragging occurs while driving, the creep phenomenon will not occur, although it is limited to AT cars. The movement of the car without stepping on the accelerator is called the creep phenomenon, and if the parking brake is applied, creep will not occur.

To check the parking brake, first check for any abnormal noise when you pull the lever. You will also hear a notch (click) before you pull the lever to lock it, but count how many times you hear it. There is no problem if the number of times is the appropriate number described in the vehicle instruction manual. The same applies to the foot-operated parking brake. Depress the pedal with your foot and count the number of notch sounds. Finally, press the unlock button from the locked state and check if it can be returned to the original position smoothly without rattling.

Next, check the function of the parking brake. The method is to stop the car on a slope and pull the parking brake lever while shifting to the N range for AT / CVT cars and to neutral for MT cars. Then lift your foot off the brake pedal and make sure the car does not move backwards. If you do not retreat here, the parking brake is functioning normally. If something goes wrong, you will need to check the brake body.