Drum brakes protect the pickup trucks and provide a consistent braking force in the forward and backward direction of the vehicle.
Why Do Pickup Trucks Have Drum Brakes? In general, pickup trucks have drum brakes due to their low installation and repair costs. They are more durable and provide great stability with a large trailer. In addition, the large contact patch and stronger wedging action of the brake shoe with the rotating drum can park and stop better.
The braking system inside the truck’s wheel consists of a brake drum that rotates with the wheel’s rotation due to the presence of its rotating cylinder.
Inside each cylinder, there is another structure present known as the brake shoes of the assembly.
The brake shoes are made up of friction material, i-e, the brake lining that plays a vital role in decelerating the vehicle in forward and reverse directions.
Why Do Pickup Trucks Have Drum Brakes?
The driver pushes the truck’s brake pedal, the brake booster present in the assembly increases its power and converts it into hydraulic pressure with the help of the master cylinder.
The hydraulic pressure then transfers to the brakes with the help of tubing filled with the brake oil; consequently, the piston moves outward.
Due to the piston’s movement, the brake lining of the brake shoes pressed against the inside of the brakes and produced a powerful braking effect.
The vehicle starts to decelerate and stop its movement due to friction production between the brake lining and the rotating drum.
Cost-effectiveness
Manufacturers like to use drum brakes in their wheel assembly due to their low initial cost.
A well-maintain braking system will save the driver from the extra maintenance expenses and prevent brake lining replacement with time.
They are durable and provide stability with heavy trailers. The replacement parts of this braking system are easy to purchase due to their reasonable sale.
Drum brakes last longer
Trucks are most commonly used for average transportation purposes; their braking system lasts longer than the vehicle exposed daily to extreme driving conditions.
The closed setup of these brakes keeps harmful material like climatic stresses and heat away from its assembly.
Brake shoes present on the backside of the assembly will increase the life of these brakes.
On the other hand, pads of disc brakes present on the front of the assembly and contract harmful material frequently.
Due to its closed setup, it is essential to inspect them with the help of professionals because performing visual inspection from the outside of the sealed assembly is not beneficial.
You need to frequently open it and get it clean and maintained with the help of mechanics.
Safety of the vehicle
Drum brakes cannot dissipate heat effectively and have low heat tolerance; due to this reason, manufacturers install them on the vehicle’s rear wheels.
The front wheels perform most of the tasks of the braking system, the reason why they face more stress and heat.
The pickups that use trailers for towing purposes use disc brakes on the front wheels and drum brakes on the rear wheels.
Another benefit is their large contact patch between the brake shoe and the rotating drum that provide an increased braking effect that can quickly spread over a larger area.
Manufacturing and repairing costs
These are cheaper to make and easy to install than disc brakes that require separate brakes installation for parking duty.
The spring that holds its components together can easily replace with the help of a simple brake tool. So, the mechanic can effectively open the sealed assembly and replaced the broken part.
Within 15 minutes, the mechanic can reconnect the drum, the springs, and the brackets back to their original place.
The closed assembly and better corrosion resistance ability of these brakes make maintenance easy and affordable.
Better parking ability and less drag
The drum brakes weigh less than disc brakes and have better parking ability due to the stronger wedging action of the brake shoe.
When the parking brake is set, any attempt to run the wheels on the road will cause the brake to grip harder on the surface.
The spring present in its assembly will pull the brake shoes back to their original place after completing the braking task and produce less or no brake drag at an average temperature.
What are the disadvantages of installing drum brakes in a pickup truck?
There are different disadvantages of drum brakes that are as follow:
Designs of the drum brakes
One of the disadvantages is the poor design of their drums that cannot pass cool air from the outside assembly toward the inside.
As a result, they cannot effectively dissipate heat from their components and braking plate.
Due to excessive heat buildup, its radius increases in size compared to the radius of the brake shoe.
Consequently, the brake lining of the assembly cannot produce significant friction against the rotating drum and does not stop its movement.
The vehicle’s braking ability starts to reduce up to 25 percent due to decrease pressure distribution between the drum and the brake lining.
Fading of brakes with time
Due to abrupt stopping and driving on the descending roads, the heat starts to build up in the drum and the brake lining and causes a significant reduction in friction.
As a result, the brakes become less effective due improper functioning of brake shoes.
In addition, the driver needs to add extra pressure on the brake pedal to increase its stopping ability because of fading brakes.
Shifting of weight loads during braking
The front wheels of the truck perform approximately 80% tasks of the braking system.
Due to this reason, they require long and thick disc brakes that can efficiently produce a large amount of friction.
During abrupt stopping, the better clamping power of the disc brake rotor can swiftly endure the weight transfer from the rear ends of the vehicle towards the front ends.
On the other hand, it can only manage light loads of rear suspension due to its lesser clamping power and low production of friction; they are suitable for the rear wheels of the trucks.
Hold water in the assembly
The closed design of these brakes can easily collect water inside their brake cavity due to rain or driving on water puddles that can significantly reduce the functionality of its components.
The removal of water and gunks from the brake cavity of the wheels is a complex process that cannot be performed correctly.
Therefore, it will considerably compromise the safety of your vehicle and cause a lot of accidents due to damaged braking parts.
Types of drum brakes in Trucks
Three types of drum brakes are present in the market that can differ due to brake shoes’ functionality.
They are also known as self-energizing brakes that contain similar components in their drum assembly; some of their functions and differences are briefly discussed below:
Leading and trailing shoe type
It contains two parts of brake shoe present on both sides of the assembly, i-e the leading and the trailing shoe.
The leading shoe moves in the direction of rotation of the drum, and the trailing shoe moves away from the rotating surface.
When you push the brake pedal, the piston, with the help of hydraulic pressure, press the leading shoe in the direction of rotation of the drum with great force and produce a powerful braking effect.
They can work in such a pattern to stop the vehicle movement in both reverse and forward conditions.
Twin leading shoe type
This assembly contains two leading shoes with separate wheel cylinders that operate on the mechanisms of the self-servo effect.
Each of the wheel cylinders contains pistons that move only in one direction.
Therefore, when the vehicle is move in a forwarding direction, both shoes act as leading ones and press against the rotating drum with a powerful braking effect.
When the truck moves in the reverse direction, they function as trailing ones.
Due to the self-servo effect, the shape of the shoe, and the drum rotation, the shoes need to be press slightly against the rotating surface because they also contain powerful springs that pull the shoes back to their original place.
Some of the mid-size trucks contain dual twin leading shoes in which the pistons move in both directions, making it feasible for brake shoes to function as leading and trailing ones regardless of the vehicle’s movement.
Duo servo type brakes
It is the advanced version of twin leading shoe brakes in which both shoes of the drum connect with an adjuster’s help.
The pressure produced by the drum brake’s wheel cylinder press the primary shoe of the assembly with its rotating surface.
It then transfers it towards the linked secondary shoe with the help of an adjuster that creates the more significant braking effect.
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