Getting to know how your car works and what options you have is incredibly useful to know, so in this video I want to run through everything you need to know about your car’s brakes, including the different parts, options for those parts, and plenty more. So, lets get into it.
First I think we should cover the components, as that’ll help you understand how it all works too. You can split your braking system into two sections. The first is your pedal, the master cylinder and booster, and the ABS pump, and the other being the individual components per wheel. Lets start with the first half.
The pedal is normally directly connected to the master cylinder, which is normally directly connected to the booster. The master cylinder is basically just a piston in a chamber full of brake fluid, and as you push on the pedal it pushes fluid out of the chamber creating pressure in the whole system. The booster is normally vacuum operated, and makes it easier to apply more force as a big diaphragm has a vacuum drawn behind it helping push on the master cylinder as you press the pedal.
That pressure, on modern cars with ABS anyway, then goes to the ABS pump. That is normally also the distribution block that splits the one line from the pedal to each wheel. That is the thing that locks and unlocks each wheel under heavy braking. On more high tech cars, they can often also help lock individual wheels for track performance or stability control.
So that’s the core system, what about the fun stuff, the bits you can easily change? Well, there are four main components on each wheel. The disc, the big spinning piece of steel – or if you are really fancy, carbon. There is also the caliper, brake pads, and the brake lines.
Let’s start with the discs. Like I said, those are normally steel, although supercars often come with ceramic or full carbon ones instead. These discs mount to the wheel directly, making them unsprung, and rotational mass. What that means is because the engine has to actually spin up the discs, the lighter they are, the quicker the car can accelerate as the less mass it has to turn. But, there is a trade-off. With metal discs, the heavier they are, the more mass they have. The more physical mass there is, the more thermal mass they have, meaning they can soak up more heat, and stay effective for longer. This isn’t so important on road cars, but when venturing onto a track you’ll find out very quickly the first thing to stop working is your brakes, because they’ll have overheated.
So, what are you options? Well, it depends on your car, but there are normally a few key words to look out for. “Vented” means it’s a double thickness disc with effective fan blades in the middle. Pretty much any performance car, and most regular cars these days, come with vented discs. “Slotted” means they’ve had slots machined into the face, which are meant to help clean the pads and ‘de-gas’ the surface, essentially let the hot gasses that form from the contact and heat escape. “Drilled” or “Dimpled” means there are, well, holes or dimples in the discs, mostly to help with weight reduction. These often crack around the holes though, so be careful.
The size of the disc matters a lot too, specifically it’s radius. The wider the disc, the more stopping power you’ll have as there is both more material grab onto, and more leverage as it’s further from the point of rotation. But, again, larger rotors means more driven weight.
Moving onto the pads, these are what contact the discs to actually slow the car down. There are so, so, so many different options for pads, so many I would have to spend hours just to explain them all, so let me summarise. There are three main types of compounds used, organic, semi-metallic, and ceramic. Organic pads are the softest, made of things like glass fibres, rubbers and a bit of metal too. These are the sort of pads that work great for everyday cars. They normally wear out fairly quickly, and produce a lot of brake dust, but they are normally the cheapest. Semi metallic is pretty similar, but a bit longer lasting. These are the most common type found these days, and can still vary a lot in feel, life expectancy and performance.
Ceramic is generally reserved for more performance focused cars. They often don’t work as well when cold – they need to be brought up to temperature before actually stopping you, but often work to much higher temperatures than the others, meaning brake fade is a lot less noticeable.
Moving onto the calipers, this is what actually presses the pads into the discs, causing you to slow down. They also come in a variety of options, but there is two main types. Sliding, or fixed. Sliding calipers are what you’ll find on the majority of cars. They have one, or maybe two, pistons on one side that push on the inside pad, and the whole thing is on a sliding rail so when the piston pushes on the inside pad, the whole caliper slides to also push on the outside pad. Generally these work fine, but lead to uneven wear on the inside pad, and don’t always have the best power or modularity.
So, fixed calipers. They have pistons on both sides, it can be one per side, two, three or even four, although four is pretty uncommon. The pistons push on each pad independently of the other side, so offer better power and control, and you don’t have to worry about the caliper wearing the pins it slides on!
Finally, the brake lines. These come in three varieties. Braided, Rubber, or hardline. Rubber and hardline is normally the most common, a mix of the two actually, with hardline being brittle and immovable, but strong. Whereas rubber is flexible, but weaker and prone to cracking with age. Braided lines are normally replacements for the rubber sections, supposedly offering better pedal feel and longevity, although some shy away as it can be hard to see damage and they have a habit of wearing through the things they rub against.
So, that’s your braking system, the parts in it, and your options for each part.
