Drum brakes are one of the great forgotten, but they still exist in both old and new cars, especially if we talk about commercial and industrial vehicles. Whatever your car, if you have come this far it is because you are surely interested in knowing how to maintain your drum brakes, and here we are going to tell you how to make them always in perfect condition.
This braking system is still valid despite the rise of disc brakes. While in the latter the circle is stopped by a clamp that has some pills inside; In the case of drum brakes we find a structure based on components and a different operation. However, the purpose is the same, to stop the running gear.
In drum brakes we find a metal drum in which the braking of the vehicle occurs as a result of some shoes activated by a hydraulic system and a cylinder in charge of activating them that are separated according to the force applied to the brake pedal. This causes a friction that comes into contact with the inner face of the drum, causing the vehicle to stop or slow down.
Drum brakes are currently reserved primarily for use on the rear end. In any case, you have to know that they are less effective brakes and that they overheat more easily than disc brakes, but they are cheaper and last longer.
Instructions for maintaining drum brakes
Being an element that is not easily visible, it is necessary to know how to maintain the drum brakes so that the car can pass the ITV inspection; and, above all, for security reasons.
There are different signs that can indicate that there is some kind of error in the system and that requires our quick action. Some of them are:
- Increased brake pedal travel. If we notice that the brake pedal has a higher stroke than usual, it can let us know that there is some type of seizure in one or both wheel cylinders, that there are leaks or that there is a problem in the automatic adjuster.
- Squeaks. We must always be aware of the sounds that come from our vehicle. These can give us valuable information to know a possible problem in this. In this case, if they are squeaks that come from the rear of our car, it could be because the shoe lining is worn and there is friction between the metal and the drum. You may also notice a deviation in the trajectory when braking.
For this reason, it is very important to carry out maintenance work on drum brakes, which will consist of a periodic review and replacement of parts if necessary. This repair may involve the replacement of different parts such as cylinder, shoe, drum, tensioner, springs and/or locks.
In the same way, you should know that it is necessary to impregnate a special brake grease in its moving parts. If when checking the drum brakes you notice that there is a rusty drum or that it has some kind of scratch, groove or crack, it will be time to replace it.
When to replace drum brakes
When it comes to knowing how to maintain drum brakes, it is important to know some information regarding when its main elements should be replaced:
- Drums. These should be replaced with new ones if they start to be deformed or have deep grooves. Also when its internal diameter is close to that indicated by the manufacturer. In general, a rear drum brake allows driving up to 80,000 kilometers, although it is advisable to carry out a review every 30,000 kilometers. Although the different elements of the kit have different durability, it is recommended to replace the entire drum brake kit at the same time.
- Shoes. On the other hand, it is very important to keep in mind that the shoes are in perfect condition. These, together with the drum, are responsible for making the effort during braking, especially when the parking brake is activated. Likewise, their friction material must comply with Regulation 90 of European legislation.
- Settlement shooting. Once the drum brake assembly is replaced, in order to achieve compensated and effective braking it will be necessary to carry out what is known as a break-in run-in. This consists of running the vehicle with the drum brake kit changed, avoiding sudden braking for at least 200-500 kilometers. To do this, you will have to be careful during the first uses that you give it, betting on a calmer driving that avoids demanding the maximum from these elements.
