JAKOPARTS –
ORIGINAL-QUALITY BRAKE PARTS

The brakes of a passenger car not only have to withstand extremely intense usage. The brake system and all its parts are also an important safety factor. And so perfectly functioning brakes are absolutely essential. Which is why they should be checked every time a car is taken for servicing. But when do brake discs and pads need changing? And how is it possible to tell when they are worn?

How long is the service life of brakes?

It is unfortunately not possible to make any generally valid statements about the service life of brake discs and pads. A number of factors govern how long brakes function properly: The working life is influenced in particular by driving style, vehicle weight and materials. Wear and tear on the brakes also depends on whether a vehicle is driven a lot on motorways or more in urban traffic. One thing is clear: Brake discs and brake pads are subject to wear over the course of time, as they convert kinetic energy into thermal energy through friction.

It is quite possible for careful motorists to get 100,000 kilometres or more out of one set of brake pads. Drivers who prefer a speedier style have to change brake pads far sooner. Intervals of 10,000 to 15,000 kilometres are not unusual. The same rule also applies to brake discs: The more intensively they are used – as a result of frequent, sharp braking for example – the sooner they have to be replaced.

When should brake pads be changed?

At the latest, brake pads should be replaced when they are worn down to a thickness of less than two millimetres. Most modern cars are fitted with wear indicators to warn drivers when replacement is due. With electronic systems, wear is accordingly indicated by a warning light in the dashboard. With the purely mechanical version, a metal pin inserted in the pad makes an unpleasant noise on reaching the wear limit as a result of the metal pin coming into contact with the metal of the brake disc.

When should brake discs be changed?

The crucial aspect with brake discs is the so-called “minimum thickness”. This is the minimum dimension that every brake disc must have and which is specified by the manufacturer. It is abbreviated to “MIN TH” and can be found on the rim or at the chamber of the brake disc. Two to three millimetres of wear are generally acceptable.

Natural brake disc wear is relatively easy to detect. When a disc is worn, a burr can be felt at the rim, as the disc only becomes worn where the brake pad is applied. The more pronounced the burr, the worse the disc wear is. Experts use special instruments to measure the thickness of the brake discs.

Our range of products has contained brake calipers right from the very beginning, and we’ve always appreciated the importance of these safety-relevant brake components. Brake calliper brackets are an essential part of the brake system and accommodate the brake pads. The brake piston presses the brake pads onto the brake disc, which brings the vehicle to a stop.

Alongside conventional deceleration by means of the service brake, the rear brake caliper also accommodates the function of the park brake, which is responsible for preventing parked vehicles from rolling away.
Conventional park brakes are actuated using a handbrake lever, whereby mechanical force is transferred to the handbrake function of the brake caliper via the handbrake lever and the handbrake cables. This presses the brake pads onto the brake discs, and the vehicle is prevented from rolling away.

In an age of automotive assistance and comfort systems, an additional type of park-brake actuation has emerged: the actuation of the park brake by means of an electric servomotor.
In this case, the actuation through mechanical force is replaced by an electrical signal that triggers a servomotor, which then applies the required force through the brake pistons.

When replacing a brake caliper featuring an electric park brake, there are a few specific details to bear in mind compared to conventional brake calipers. Below, we will talk you through these step by step.

How to replace a brake caliper:

Step 1:

Connect the OBD diagnosis unit to your vehicle and follow the instructions for changing the brake caliper. This usually involves resetting the brake piston.

Step 2:

Raise the vehicle and remove the wheels.

Step 3:

If an electric wear indicator is installed, the plug connections must be disengaged.

Step 4:

Release the cable connectors for the electric park brake and inspect the cable and the plug connector for visible damage and corrosion.

Step 5:

The brake hose must now be removed from the brake caliper. Our stopper set for hoses and pipes (article no.: J9300000) can be of use for sealing the line while repairs are ongoing. This prevents the irritation of brake fluid leaking out during the repair process

Step 6:

The brake caliper can now be removed. At this point, check whether the brake pads and brake discs also need to be replaced.

Step 7:

The new brake pads and brake discs are now installed provided they need to be replaced. If this is not the case, ensure that the old brake pads run smoothly within the guide and do not jam. If necessary, clean and re-lubricate them.

Step 8:

Now install the new brake caliper with self-locking bolts. Observe the torque specifications provided by the vehicle manufacturer.

Step 9:

The brake hose is now fixed in place on the brake caliper with new seals.

Step 10:

Connect the plug connectors for the electric wear indicator (provided they were previously installed) and connect the cable connection for the electric park brake to the brake caliper’s housing.

Step 11:

Bleed the brake system in accordance with the vehicle manufacturer’s specifications and check that your brake system is free from leaks.

Step 12:

Check the level of the brake fluid and top it up if necessary. When doing so, observe the specifications in the vehicle manufacturer’s operating instructions

Step 13:

Calibrate the electric park brake using the OBD diagnosis unit.

Step 14:

Install the wheels and tighten the wheel bolts to the appropriate torque level in accordance with the vehicle manufacturer’s specifications.

Step 15:

Test the brakes on the brakes tester and perform a test drive.

Getting from 100 down to 0 needs to be quicker than going from 0 to 100!
The brake system is extremely complex. Nowadays, ever more brake components need to be checked and tested in order to keep driving as safe as possible. Correct brake servicing is absolutely crucial for this purpose.

We find ideal solutions for our customers – whatever their problems might be.
When doing so, we need to keep the following points in mind, among others:

• Which tasks/processes would it make sense to improve?
• Can the tools in question be used universally?
• Is the design of the tools and the packaging clever, robust and compact?
• Can our customer offer his own customer a time advantage thanks to this tool? This point is especially important: after all, everyone is short on time these days.

When it comes to the points above, we always try to gather suggestions and ideas from our customers’ day-to-day workshop experience and take them into account when developing new products. The following tools ought to be included in a thorough brake service:

Fill/bleed unit (J9300001) :

This device is absolutely indispensable for a scheduled service. It is also used for bleeding the hydraulic system and refilling it with fresh brake fluid after replacing various components in the brake system or clutch system.
To do so, our fill/bleed unit does not require any electrical or compressed-air connection, which makes mobile use possible.
You can find step-by-step instructions here.

Pliers for brake spring washers (J9350000):

These pliers ensure a secure grip on the outside of the spring cap, meaning you will no longer have to fumble with needle-nosed pliers or any other tools that are not actually intended for this application.

Stopper set, hose/pipeline (J9300000): 

Using these special pliers, we avoid the significant mess caused during replacement of the brake lines or brake callipers by simply sealing the line using the pliers.This prevents any fluid from leaking out of the open line. In addition, this stops the hydraulic circuits from “running dry”, which would involve a great deal of effort to bleed the ABS control unit and/or the ABS hydraulic unit.

Reversible-ratchet set (J9300003):

The central opening in the ratchet and the sockets is what makes this set so special: the bleeding hose is guided through this opening, which also prevents it from sliding off. In other words, there are no longer any issues with space, even when the wheel is installed. This also makes the irritation of fixing and turning a spanner on the bleed nipple a thing of the past.

Turn/reset tool, brake calliper piston (J9321000):

The reset tool is a tool for all rear-axle brake callipers that feature handbrake actuation. These brake pistons not only need to be pushed back, but also turned at the same time. The compact design of our set of reset tools is what makes it so special: we are able to cover a very wide range of applications with two individually adjustable adapters.

Vernier calliper, brake disc thickness (J9330000)

You know that feeling when you have to tell the customer that their brake discs need replacing together with the brake pads? This is not a problem with our vernier calliper: it has been especially designed for this task and means that the wheels no longer need to be removed.

You can find even more information about brakes and brake service here.