Analyze 9 pain points of brake drum

In this paper, the common brake drum failure state is summarized, and a certain degree of brief analysis, to share with you.

Uniform overwear

Due to a series of reasons such as large brake resistance, brake imbalance and dust impurities, the brake drum is rapidly and evenly worn. This will form a very obvious step ring on the edge of the brake drum.

Abnormal wear on one side

Sometimes it will be found that the inside of the brake drum has obvious wear marks on one side, and no obvious wear marks on the other side.

This is due to the different hearts of the brake drum and brake, further analysis, because the brake drum and hub are rigidly connected coaxial rotation, if there is no abnormal phenomenon in the hub, the possibility of the brake drum and hub eccentric rotation at the same time is less.

Then we need to consider the installation accuracy of the brake shoe more, and we need to check the series of parts such as the brake bottom plate, the brake bracket, and the brake shoe pin one by one.

Uniform hot crack

Due to the heavy truck long time down the slope, the brake drum heat capacity is insufficient, which leads to the formation of uniform and fine turtle cracks on the friction surface, and the turtle cracks will continue to spread, lengthen and deepen. When the length of the turtle crack increases to 30 ~ 40mm, it needs to be replaced in time, otherwise it is easy to form serious faults such as brake drum cracking and affect the normal use of the vehicle.

Local heat (black) spots

When the brake drum is unevenly heated, local heat (black) spots may be produced, some neatly cover the entire friction surface of the brake drum, forming a uniform parallel ring, and some will appear in a larger local area or form a uniform distribution of small circular spots.

This is mainly due to the uneven wear caused by the material and structural errors of the brake drum, and the brake drum needs to be replaced in time when the above spots are more obvious.

Brake drum groove

The pull groove refers to the formation of deep nicks or grooves and other dents on the inner circumferential working face of the brake drum, the depth is greater than 2.5 mm, the width is greater than 0.8 mm, which is due to the abnormal wear of the friction sheet leading to the exposure of rivet, rivet and other sharp objects in the inner circumferential working face of the brake drum to form a pull groove. At this time, you need to replace the brake drum and friction plate at the same time.

Brake drum blue

The inner circular working surface of the brake drum is blue, and the brake drum and brake are likely to have been damaged or deformed. Because the blue color of the brake drum proves that it generates extremely high temperatures during operation. At this time, the relevant parts need to be carefully inspected and analyzed, and the failed parts are completely replaced.

Brake drum off the bottom

The brake drum and the wheel hub are connected together by a ring of flange bolts (also wheel bolts), and the braking force generated by the brake drum is transmitted to the wheel hub through the flange bolts to limit the rotation of the wheel.

Brake drum bottom off refers to the circular working part of the brake drum (cylinder) and the flange part (disc) off, resulting in brake failure, the main reason is due to the structure and material improper factors in the manufacturing process of the brake drum.

Brake drum bolt hole worn

Brake drum bolt hole wear, usually because the flange bolt (wheel bolt) is not completely tightened, the brake drum relative to the wheel hub radial and axial will occur relative movement impact, resulting in abnormal wear and deformation of the brake drum bolt hole, wheel bolts, wheel hub and other related parts will also occur irreversible serious failure, at this time need to replace all the relevant parts.

Wheel hub grease pollution

When the hub oil seal fails and the lubricating oil/grease is thrown to the inner circumscribed working surface of the brake drum, the inner working surface is seriously polluted and still not treated in time, at this time the lubricating oil/grease will further penetrate into the inner circumscribed working surface of the brake drum, this damage is difficult to reverse, because the oil/grease has actually penetrated into the inside of the brake drum.

At this time, the working friction pair formed by the inner surface of the brake drum and the friction plate has been broken, which is prone to vehicle safety failure, so the brake drum needs to be replaced immediately.

                                                                                                                                                                                                                         This article is reproduced from Truck Home, if there is any infringement, please contact the author to delete