03
2026
-
04
After the brake pads become thin and produce a braking gap, how should it be adjusted?
At present, most medium and heavy trucks on the market use air brakes, and the vast majority use drum brakes, with camshaft-type being the majority among them.
The braking system accounts for a considerable proportion of accidents caused by long-distance driving. Minor issues can cause tire blowouts, while severe cases can lead to vehicle fires and fatalities. Every driver should regularly check the braking system, paying particular attention to the brake clearance and the thickness of the brake pads.
▎Camshaft Brake Clearance Adjustment Method
The following mainly introduces the method for adjusting the clearance of camshaft brakes. Its working principle is:
Compressed air enters the brake cylinder, and the push rod of the brake cylinder is pushed outward under air pressure, driving the adjustment arm to move. The adjustment arm drives the camshaft to rotate, and the S-cam at the other end of the camshaft pushes the brake shoes outward to contact the brake drum, generating braking force, allowing the vehicle to slow down and stop.
After the vehicle has been driven for a period of time, the brake shoes gradually wear thin, and the brake clearance increases. If not adjusted in time, even when the brake cylinder is fully extended, the brake shoes may not contact the brake drum, or even if they do, they will not generate force, resulting in a lack of braking.
From the diagram, you can see that the key component that can be adjusted inside is called the adjustment arm. By adjusting it, you can adjust the brake clearance. So, how do you adjust it?
Many drivers like to leave this dirty and technically simple task to mechanics. Actually, adjusting the brake clearance really isn't very technical, but if you want to make sure your car is fine, you still need to pay attention and do it yourself.
Adjustment arms can be divided into manual adjustment arms and automatic adjustment arms, which can be distinguished by a few small features. Manual adjustment arms have a long deployment time and good reliability.
You can adjust the brake clearance through the adjusting nut inside the locking device above: Open the observation hole on the dust cover, observe the rotation direction of the adjusting nut that reduces the brake clearance (usually clockwise), stop when there is no gap and the force has obviously increased, and then rotate 180° in the opposite direction. That’s how the adjustment is done.
The adjustment method for the self-adjusting lever is the same, except that because there is an internal self-adjusting mechanism, you will hear a 'clicking' sound when turning the nut.
Self-adjusting levers generally do not require manual adjustment, but the quality of most self-adjusting levers on the market is concerning. Some may fail to function, and some may even cause the braking clearance to become smaller or the wheels to drag.
At this time, it is necessary to check whether the adjusting lever is working properly, which can be measured with a ruler. Adjust the brake clearance according to the method above, then release the parking brake, press the foot brake, and keep it pressed. Another person needs to measure the push-out length of the brake cylinder push rod. The push-out lengths on the left and right should be the same or similar. If there is an anomaly on one side, it needs to be closely monitored.
Previous Page
Previous Page
Focus on the research and development of automotive brake systems and pneumatic brake valves to promote the development of the auto parts industry!
Contact Information
Telephone:86-575-87438928
Mobile:8613252110178
QQ：1185450863@qq.com
Address: No. 461, Advanced Village, Fengqiao Town, Zhuji, Zhejiang Province
Online message
Submit your information and we will contact you as soon as possible.