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Replace Manual/Automatic Slack Adjuster On Trailer Or Truck Wholesale - Longway Machinery

Longway Machinery is one of the leading Replace Manual/Automatic Slack Adjuster On Trailer Or Truck Wholesale Manufacturers, Our product quality has passed international certification, and the price is affordable, welcome to call and order our products wholesale.

Slack Adjuster

Slack adjuster equipment (snubbers) used in multiple trailer operations, whether on the trailers or on the converters, shall be maintained in proper working order.


Slack adjusters (also called brake adjusters or just "slacks") regulate the distance that the air brake has to travel to apply friction to the wheel. This distance increases as use of the brake causes the friction material of the brake shoe to wear away. When the brake is used, the operating rod pushes out on the slack adjuster which then turns the S-cam. The S-Cam Brakes pushes the brake shoes apart which applies friction and slows the vehicle. Without this function, the air brake can become out of adjustment and the vehicle may lose its capability to slow or stop consistently.


Air brake slack adjuster-European Type 72523C

When you need to replace your slack adjusters, it is very important to find the correct part that matches your equipment to ensure a safely operating braking system. It's easy to find the correct replacement slack adjusters for your truck, tractor or trailer. First, the type of slack adjuster should be considered. Slack adjusters are available in two types: manual slack adjusters and automatic slack adjusters.


Manual slack adjusters compensate for the distance in the brake linkage by adjustments made with a wrench.

Automatic slack adjusters remove the slack in the brake linkage without the need for manual adjustment.


Both manual and automatic slack adjusters have three qualifications which can be easily measured. Finding these three measurements is the key to finding the correct slack adjusters.


Automatic Slack Adjuster


An automatic slack adjuster is a mechanical component of the air brake system that adjust brakes as necessary when the vehicle is in operation to compensate for wear in the brake shoes (drum brakes) or pads (disc brakes). When an ASA is found to be out of adjustment, it signifies the existence of a larger braking system problem that needs correction.


Manual adjustment of ASAs should only be done by qualified technicians during installation or when absolutely necessary to move the apparatus to a repair facility (NTSB 2006, 2007; IAFC 2006).


How Automatic Slack Adjusters Work?

You may be wondering how slack adjusters work within your air brake system. The answer is less complicated than you might think. Slack adjusters adjust the brakes to make up for wear on the lining. When the brake is applied, a rod pushes out the slack adjuster. The slack adjuster then turns the s-cam, which forcing the brake shoe apart. Then, the mechanism applies the force necessary to stop a truck.


How to Adjust Automatic Slack Adjusters on Trailer Brakes


Step 1

Before beginning your adjustment, it is important to block the tires to prevent the trailer from moving. The best way to avoid movement is to raise the vehicle on jack stands during the adjustment. Have the brake system at full pressure, lower the emergency brake, and push in the air valve, thereby releasing the brakes. Listen for any air leaks, as they can decrease your braking ability. Using a piece of chalk, mark the push rod where it leaves the air chamber.


Step 2

Using a screwdriver for leverage, pull the push rod out of the air chamber, and measure from the chalk line to the air chamber. That shows you the "stroke range"; anything more than three-quarters of an inch would mean the brakes need an adjustment.


Step 3

Locate the manual slack adjuster bolt. It connects the s-cam to the air chamber on the axle housing with the push rod. Using the appropriate sized wrench, turn the slack adjuster. Watch the s-cam to see the direction it is moving to ensure you are adjusting it correctly. You can tell you are adjusting it the wrong way if the push rod is pulling out of the air chamber. Continue tightening until you feel resistance, which means you have drawn the brake linings to the drum.


Step 4

Reverse the slack adjuster one-quarter to one-half of a turn to put a little distance between the drum and the linings.


Pressurize the system and apply the brakes using normal pressure. You should have no more than one-tenth of an inch between the brake linings and the drum, and there should be no more that 2 inches of travel in the push rod stroke.


Manual/Automatic Slack Adjuster Replacement



Slack Adjuster is composed of three relays. One is responsible for adjusting the output voltage of the generator. It connects and separates the magnetic field excitation of the generator to different circuits through the relay contact, so as to control the excitation current of the generator and realize the control of the generator. The purpose of output voltage stabilization; one is responsible for preventing the charging current from being too large.


When the charging current is too large, the circuit will make the voltage stabilizing relay and the current limiting relay act at the same time, disconnect the excitation circuit of the generator, and stop the generator; the other is responsible for cutting off the charging circuit when the reverse current occurs. When the current flows, the relay operates to cut off the charging circuit.


Advantages of Slack Adjuster

Easy to use

Can be used on any slack line

Allows you to adjust the slack line to your desired length

Increases the stability of the slack line

Comes with a carrying case


ADVANTAGES of Slack Adjuster


China Slack Adjuster Manufacturers


Find Slack Adjuster for your production line Get more details of Slack Adjuster from Longway Machinery and contact us to get price quotation. Longway Machinery is one of the leading Slack Adjuster Manufacturers, Our product quality has passed international certification, and the Slack Adjuster price is affordable, welcome to call and order our products wholesale.

Besides Slack Adjuster, we also have other types of air brake system components, want to buy them in bulk, contact us.

Besides Slack Adjuster, we also have other types of air brake system components, want to buy them in bulk, contact us.



Email: luping@hzroadage.com

Add: Xishan Industrial Area, Renhe, Yuhang District, Hangzhou,China, 310006

Hangzhou Longway Machinery Co., Ltd Support By Hangzhou Great Master

Hotline:: +86-571-86575535

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