Some time ago, a Mercedes Benz car came to the maintenance shop. At present, the car has driven more than 85000 kilometers. The owner described the fault to the repairman. Now his car can always hear squeaking noises when driving or stepping on the brake, and the brake fault light is on and does not go out.

其實(shí)，這輛奔馳車(chē)在上次做保養(yǎng)的時(shí)候，修車(chē)師傅就檢查到該車(chē)的剎車(chē)片該換了，可能當(dāng)時(shí)車(chē)主確實(shí)有事，也或許是不太相信修車(chē)師傅所說(shuō)的話(huà)，反正當(dāng)時(shí)給推辭了沒(méi)有更換，這不跑了還不到1千公里就出現(xiàn)了問(wèn)題。

In fact, when the Mercedes Benz was serviced last time, the repairman checked that the brake pads of the car should be replaced. Maybe the owner was really busy at that time, or maybe he didn't believe what the repairman said. Anyway, he refused at that time and didn't replace it. After not running for less than 1000 kilometers, there was a problem.

由于修車(chē)師傅已經(jīng)知道哪里出了問(wèn)題，所以接過(guò)車(chē)后就直接就把剎車(chē)片拆了下來(lái)，從下圖中可以看到，剎車(chē)片上的報(bào)警線(xiàn)已經(jīng)被磨損去了一大半，這就證明剎車(chē)該換了。

Since the repairman already knew what was wrong, he directly removed the brake pad after receiving the car. As can be seen from the figure below, more than half of the alarm line on the brake pad has been worn, which proves that the brake should be replaced.

奔馳車(chē)主看到剎車(chē)片磨成這般模樣，毫不猶豫同意修車(chē)師傅更換掉，下圖這是修車(chē)師傅讓車(chē)主觀看新舊剎車(chē)片的對(duì)比，左邊的新剎車(chē)片明顯要比右邊的舊剎車(chē)片要厚很多。

The owner of Mercedes Benz saw that the brake pads were ground like this and did not hesitate to agree to the repairman to replace them. In the figure below, the repairman asked the owner to see the comparison between the old and new brake pads. The new brake pad on the left is obviously much thicker than the old brake pad on the right.

不過(guò)修車(chē)師傅在拆卸剎車(chē)片的過(guò)程中，還發(fā)現(xiàn)因剎車(chē)片沒(méi)有及時(shí)更換，還導(dǎo)致了剎車(chē)盤(pán)受到了一定的磨損，剎車(chē)盤(pán)的邊緣凸起了很多，修車(chē)師傅表示，這一情況是需要處理的，不然安裝上新剎車(chē)片后就會(huì)出現(xiàn)異響的問(wèn)題。如下圖所示；

However, in the process of removing the brake pads, the repairman also found that the brake pads were not replaced in time, which also led to certain wear on the brake discs, and the edges of the brake discs bulged a lot. The repairman said that this situation needs to be handled, otherwise there will be a problem of abnormal noise after installing new brake pads. As shown in the figure below;

奔馳車(chē)主得知這一問(wèn)題后，趕緊問(wèn)修車(chē)師傅這該怎么處理呢？只見(jiàn)修車(chē)師傅把剎車(chē)盤(pán)拆卸下來(lái)，之后固定在一個(gè)機(jī)器上便開(kāi)始打磨了起來(lái)。修車(chē)師傅這樣的維修辦法，讓車(chē)主很擔(dān)憂(yōu)，本來(lái)剎車(chē)盤(pán)的厚度就很薄了，這經(jīng)過(guò)這么一打磨豈不是更不安全了嗎？

When Mercedes Benz owners learned of this problem, they quickly asked the repairman how to deal with it? The mechanic took down the brake disc, fixed it on a machine and began to polish it. The maintenance method of the car repairman worries the car owner. The thickness of the brake disc is very thin. Isn't it safer after such polishing?

修車(chē)師傅得知奔馳車(chē)主的擔(dān)憂(yōu)后，向車(chē)主解釋到，這是在鏜盤(pán)，只是將剎車(chē)盤(pán)邊緣凸起的部位鏜掉，而并非是在對(duì)剎車(chē)盤(pán)厚度打磨，更不會(huì)影響到安全問(wèn)題，奔馳車(chē)主聽(tīng)到修車(chē)師傅的解釋后，這才把心放了下來(lái)。

After learning about the concerns of Mercedes Benz owners, the repairman explained to the owners that this was boring the disc, only boring the convex parts at the edge of the brake disc, not grinding the thickness of the brake disc, and it would not affect the safety problem. Mercedes Benz owners relieved themselves after hearing the explanation of the repairman.