Brake booster (BKV) defective: this must be taken into account now!

Does the vehicle have a damaged brake booster (BKV)? Then in the following article there is important information about the signs, the repair / the change and the costs. But first a brief overview of the function of the brake booster and the consequences if it is defective. When pressing the brake pedal multiplied the brake booster the pedal force of the driver. The increased pedal force is passed on to the brake caliper and its piston via the master brake cylinder with the brake fluid. A functional impairment or damage is caused by, among other things wear caused, the master cylinder can, among other things leaky will. This significantly increases the force required to operate the brake pedal.

Symptoms - defective brake booster

There are several symptoms of a brake booster that is no longer working properly:

• The brake pedal cannot be depressed when the engine is started.
• After starting the engine, a hissing sound can be heard near the brake pedal.
• It is much more difficult to brake the car (it has a longer stopping distance than before).
• The brake pedal does not become "soft" when the engine is started.
• When the engine is running, the resistance from the brake pedal is the same as when the engine is switched off.

In order to checkTo check whether your brake booster is still working, proceed as follows: With the engine switched off, press the brake pedal three to five times until it only comes back slowly. The foot remains on the brake pedal. Then you start the engine, the brake pedal should now give way again and become "soft". If this is not the case, it can be assumed that the brake booster is damaged.

Driving with defective brake power assistance and the subject of the main inspection!

Continuing to drive with a defective brake booster is not only a risk for you, but also for other road users. Even if braking is still possible with significantly increased effort, the safe and reliable function of the braking system is no longer given. And the lack of brake booster is one in the main inspection serious deficiency The new general inspection sticker is of course available in this case not.

confusion possible: if the braking function is no longer sufficiently available, other components of the braking system can also be the cause, such as a leaking vacuum pump or a damaged vacuum line. It is imperative that an inspection be carried out in the workshop in order to clearly determine the source of the interference.

Change / repair of the brake booster!

With a damaged brake booster remains only the possibility of exchange. A new part must be installed, for safety reasons a repair is allowed not be considered. Replacing the brake booster should discord be carried out in a specialist workshop, as it is a safety-relevant component. Depending on the vehicle model, there are different procedures for changing the component. Before the faulty brake booster can be replaced, in most cases it must first be replaced Parts of the brake system are removed, such as the brake pedal, brake lines, master cylinder and vacuum line. The brake system must be opened and then bled. It is therefore advisable to have the entire brake fluid replaced at the same time. Manufacturers of brake boosters are the companies Bosch, ATE or TRW.

Costs of replacing the brake booster!

For a new part, you have to reckon with pure material costs of between 50 and 500 euros. The cost of the new brake fluid is between 20 and 80 euros. The working time for changing the brake booster in the workshop can vary greatly, depending on how many other components have to be dismantled. The time required can be between one and a half and four hours. The labor costs at an hourly rate of 100 euros are between 150 and 400 euros. According to our calculation, the total costs for replacing the brake booster add up to between 220 and 1.000 euros. To note: If, for example, only the vacuum line is diagnosed as the cause of the failure and replaced, the replacement costs are of course significantly reduced. The total costs can then be estimated at around 50 euros (half an hour of work + material costs of around 10 to 20 euros).

Brake booster – the function in detail

Pressing the brake pedal would require significantly more effort without the brake booster. The power boost is generated by vacuum, which is generated either by the engine intake tract or an additional vacuum pump. The vacuum causes the pedal force support with the help of the membrane inside the brake booster. The required pressure difference on the two sides of the membrane is created by pressing the brake pedal, whereby the vacuum side is sucked in and thus increases the pedal force on the push rod to the master brake cylinder. The brake booster only works when the engine is running! As soon as the engine fails, the brake booster stops no longer available and considerable effort is required to depress the brake pedal. That should definitely be the case with any tow away be taken into account by the vehicle.

Of course, that wasn't the end of it!

tuningblog has countless other articles on the subject of car and auto tuning in stock. Do you want to see them all? Just click HERE and look around. In part, we would like to provide you with news but also off the tuning. In our category Tips, products, information & Co We have reviews of car or accessories manufacturers, new ones Tuning Wiki Terms or one or the other Leak veröffentlicht. Following an excerpt of the last articles:

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