Brake Shoes Manufacturer

In a drum brake system, the brake shoe stands out as one of the most important components. It contains the material that slows down the rotating drum, which makes it an essential part of the braking system. In this guide, we expound on the function, working, and other essential tips about brake shoes.

Brake Shoes Definition

To start us off, the brake shoe meaning.

Brake shoes are components used in drum brake to slow down or stop the motion of a vehicle. They are usually mounted on a backing plate and positioned inside the brake drum. The drum itself attaches to the wheel hub and rotates together with the wheel.

In a typical car brake setting, brake shoes are installed inside a brake drum in pairs. There is the primary or leading shoe, which is usually a shorter length, and a longer secondary or trailing shoe. The primary brake shoe is normally placed in the vehicle’s front side, the secondary shoe the back.

Before disc brakes became commonplace, brake shoes were the standard braking parts in most vehicles. Today, brake shoes are commonly found in the rear wheels, the front axle being equipped with the more versatile brake pads.

Brake shoes have their up and downsides. We will be seeing about that later. For now, let’s take a look at the parts that make the shoes and the mechanical components that support their working.

Brake Shoe Parts

The brake shoe assembly is a steel frame that features a curved profile. This is to match the circular drum inside which it operates. The frame comprises 3 main parts: the lining, rim, and web. Below is a description of each.

Brake Shoe Lining

The lining is the layer that generates friction to stop the wheel rotation. It’s also the most important part of the assembly as it determines the performance of the brakes. That, in turn, means the level of safety to expect when driving.

The lining is expected to provide friction without failing, even when operating under extreme heat, wetness, or any other braking situations. Different materials are available depending on the required brake shoe lifespan, performance, and other factors.

There are two main options for the lining; completely organic and semi-metallic. The materials used consist of abrasives, performance modifiers, lubricants, fillers, and a binder which is usually a high-heat resin.

Organic lining is among the most common brake shoe material despite its rapid rate of wear. Semi metallic linings offer better bite and last a long time. The brake shoe lining is usually bonded or riveted to the supporting frame. Bonded linings are more popular than riveted types.

Brake Shoe Rim

The rim refers to the curved part onto which the friction material attaches. When the brake shoe is the riveted type, the rim holds the rivets. It also provides the surfaces for adhesive in adhesive-bonded brake shoes.

Steel is usually used to make the rim. Aluminium moulé is sometimes also used, but mostly for lighter applications. Aluminum offers the advantages of low weight and better heat dissipation, although at the expense of strength.

Brake Shoe Web

This is the part that is welded to the rim on one side. It provides structural support to the rim and attaches the assembly to the backing plate. The web contains points and openings to attach various hardware. This part is also made from steel for structural strength.

Other Parts

Drum brakes are complicated mechanisms that involved many different parts. For the brake shoe to perform its function, several mechanical components are required. These attach to the shoe’s frame and help in one way or another. They include:

Hold down springs- the hold-down springs secure the brake shoe assemblies to the backing plate. By applying slight and consistent pressure, the spring ensures the brake shoe keeps to the backing plate, and the lining remains in its proper position.

Return springs- These are strong spring whose ends attach to either shoe. The spring’s function is to pull back the brake shoes when you release the brakes. This allows the wheels to rotate freely after the braking action. A brake spring return spring should always be stout, or its working will not be reliable.

Wheel cylinder- also called the hydraulic pressure cylinder, it connects to the brake lines and receives brake fluid during braking. The cylinder contains pistons that move outward to push the brake shoes toward the brake drum’s friction surface.

Auto adjuster- the brake shoe adjuster is a mechanism that allows the friction lining to maintain the right clearance with the drum’s surface. It adjusts the brake shoe position to compensate for the wear on the lining. The mechanism consists of springs, adjuster lever, and other components. In newer car models, the adjuster works automatically.

Handbrake cable- the handbrake connects to the brake shoe assembly through a system consisting of a cable, lever, and springs. When tensioned, the cable pushes the brake shoe lining to the brake drum’s surface.

Brake Shoe Function

Brake shoes stop a car by exerting pressure on the internal surfaces of a drum. The drum’s surface is designed to produce sufficient frictional force but also to wear slowly. The brake shoe lining, too. The arrangement enable the two surface to produce stopping force. Here is the brake shoe working explained.

• When you apply the brakes, the force converts into hydraulic pressure in the brake fluid. Through a system of pipes, the pressure reaches the brake fluid in the wheel cylinder.
• The wheel cylinder has two pistons. The pressure of the fluid forces the two pistons to thrust outwards.
• The pistons are connected to the upper part of the brake shoes via pins.
• The pins, therefore, push the brake shoe set when acted upon by the wheel cylinder pistons. This causes the brake shoes to make contact with the inside surface of the drum they are placed in.
• The brake shoes contain a lining made of friction material. When pressed against the rotating drum, the resulting friction causes the drum and, therefore, the wheels to stop rotating.
• Upon taking your foot off the brake pedal, the brake shoes pull back to their resting position with the help of return springs.

The friction generated by the brake shoe lining rubbing against the brake drum produces a lot of heat. This is what causes a vehicle to stop. The kinetic energy of the spinning drum gets lost in the form of heat or thermal energy.

Away from the science behind brake shoe operation, let’s now look at how these components are designed differently.

Brake Shoe Design Differences

The set of brake shoes used in motor vehicles are usually not identical. Each features slight design differences to cater to the different application needs. These range from the shape of the assembly, size of the lining, to the type of support components. Here is a look at these design differences.

Forward and Rear Brake Shoe

The brake shoe installed toward the front side of the vehicle is usually a different design from the rear one. The two are also identified by different names. In a duo servo brake drum, the front shoe is called the primary and the rear secondary. The non-servo design has the shoes going by names “leading” and “trailing”. The leading shoe is positioned in front and the trailing shoe the back.

Sliding and Pinned Brake Shoe

The brake shoe is either floating (sliding) or pinned. In the pinned design, the bottom part revolves in a post attached to the backplate. With the sliding type, the brake shoe comes with an end that slides on a surface. The shoe is then secured to the backplate by springs. This arrangement offers the advantage of self-alignment. It also allows the brake shoe to bed in with ease.

Short and Long Brake Shoe Lining

Primary and secondary brake shoes perform slightly different braking roles. In the popular servo action system, the primary shoe works by applying pressure to the secondary shoe. As a result, its lining is made shorter than that on the secondary shoe.

Altering the arrangement during brake shoe installation would change the performance of the brakes. It would also result in several problems such as reduced lining lifespan. That is because the lead shoe is designed for its position specifically. The same with the trailing shoe.

Brake Shoe Specifications

For optimum performance and reliability, brake shoes must work within certain specifications. These involve both the shoe’s position and the condition of its various components. The specifications also include the operational relationship between brake shoes and drums. They include:

Friction coefficient- the coefficient de frottement is dependent on the physical condition of the linings of both the brake shoe and drum surface. It also depends on whether the brake shoe is leading or trailing. Debris, water, oil, and other contaminants affect friction, too, and their presence or absence can determine the braking force. A value of 0.2 to 0.45 should be maintained.

Clearance- the right clearance between the brake shoe and drum determines the performance of the brakes. It’s usually made tight to prevent the entry of debris, water, and contaminants that would cause the brakes to fail. The tight clearance also enables a feel of the pedal. Normally, a 0.020-inch clearance is recommended.

Thickness the lining on brake shoes usually has the minim thickness allowable. It ensures optimum braking performance and reliability in stress braking. If the brake shoe thickness goes below the manufacturer, you can easily experience brake failure. Most manufacturers recommend 1/16 inches of friction material thickness.

Brake Shoes Vs. Pads

A brake shoe and brake pad both contain a friction liner, which is the main part that aids their working. Despite that, their performance, ability to withstand damage, and working mechanisms are different in many ways. Here is a comparison of the two components.

Brake shoes are used in drum brake and usually hidden from view inside the drum. Brake pads are friction materials used in disc brake systems. They are usually visible and easy to inspect than brake shoes.

In terms of design, car brake pads are made in a rectangular shape while brake shoes feature a curved profile. To generate friction, brake pads make contact with circular devices called brake rotors. Brake shoes move to press their lining against the brake drum.

Brake pads are easier to service. They are usually within reach, plus their exposed nature allows them to be self-clean. Brake shoes work in enclosed drums, which makes them prone to a buildup of debris. They are also not easy to reach and have many different components attached to them.

Brake Shoe FAQs

Brake shoes are among the least known about vehicle parts, partly due to their minimal usage in vehicles. So we included questions that many people have asked about them.

Q1. Can a vehicle use both brake shoes and pads?

A. It can but not on the same axle. Also, brake pads are better suited for the rear wheels where braking requirements are moderate. Many cars today utilize disc brake in the front and drum brakes in the rear.

Q2. What is the brake shoe lifespan?

A. Most brake shoes last about 50 000 miles, although much depends on usage and how well you maintain the braking system. Things that can shorten the life of brake shoes include a damaged brake drum surface that wears the brake shoe lining too quickly, a warped drum, and contaminants settling on the friction material surface.

For extended lifespan, it’s recommended to choose the brake shoe material that fits your vehicle application and braking needs. If you are always braking aggressively, you would need to find a material that can stand up to heat and brake fade, among other needs.

Q3. What are the signs of bad brake shoes?

A. Symptoms include brake shoe noise when braking, decreased braking performance, and the car pulling to one side when you step on the brake pedal. You may also experience brake grab, especially if the problem involves damage to both the brake shoe and supporting components. The hand brake not working or feeling loose is also another sign to look out for.

Most of these symptoms result from brake shoe wear, especially if it’s unbalanced or excessive. Brake shoe uneven wear shows up quickly, sometimes even before the shoes have served any useful life. You should replace the brake shoes or lining before wear exposes the rivets, or before the manufacturer recommended thickness is reached.

Q4. How much does it cost to replace brake shoes?

A. Although amounts vary by region, expect to pay as low as $150 to as high as $300. The brake shoe replacement process takes time and may need several other components to be cleaned or replaced. These are some of the reasons to expect extra charges when replacing brake shoes. You can also choose to do everything yourself, especially if you have experience with servicing other parts.

Q5. Can you replace brake shoes on one wheel only?

A. Brake shoe change should involve the drums on both sides of the axle. This is to ensure balanced braking. It’s also easier and more cost-effective to have the parts on both sides replaced than making separate visits to the repair shop. When changing the parts, it’s advisable to also inspect the drum and fix imperfections. Repair options include cleaning the surfaces or machining them.

Q6. Can brake shoes be relined?

A. Yes, one of the repair options for brake shoes is relining them. The process involves attaching a new friction material to replace the worn lining. It’s possible both riveted and bonded brake shoes. Only specialists should carry out relining since it requires a careful and expert approach to ensure a strongly attached friction material.

Q7. What is the average brake shoe price?

A. It depends on many factors such as quality, brand, and more. The amount varies between $20 for the cheapest brake shoe set to around $10 000 for high-end options. To ensure the most reasonable prices, many buyers choose to purchase the components online. There, they can hop from shop to shop looking for the best deals and discounts.

Online shopping also allows you a glimpse of the brake shoe price list so you can make a comparison. When scouting for deals, it’s good to weigh the option of quality against brake shoe cost. High prices may not always mean quality, but prices that are too low are not any better. Moderate prices are the better bet.

Conclusion

Brake shoes are an integral part of the braking systems of many cars today. Although dated, a good number of vehicles continue to use them, including recent models. They remain important parts, especially owing to their function as safety components. We believe this guide has helped you to understand brake shoes more deeply.