Hella Pagid Brake Systems is the joint venture between TMD Friction and HELLA, two of the biggest names in the automotive aftermarket. Drawing on decades of experience as an Original Equipment Manufacturer (OEM) for some of the worlds leading automotive marques, Hella Pagid brake systems are synonymous with premium quality aftermarket braking components (more…)
Squealing or squeaking brakes are a common occurrence when you’re at the track, but when you’re sitting in peak hour traffic on your way to work or in the city for a night out, the high pitched squeal can not only be annoying but even a little embarrassing!
Common Causes of Squealing Brakes
1. Worn Brake Pads
Squealing brakes can occur for a variety of reasons, with the first and foremost being worn out brake pads. Most brake pads have a small metal finger on the side of them which protrudes about 2mm past the backing plate. Once your brake pads have worn out, the metal finger begins to contact the brake disc. This results in that high pitched squeak we’ve all heard at one time or another. The manufacturer does this so that you’re prompted to have your brakes looked at and changed.
2. Glazed Brake Pads
The other very common cause of squeaking brakes is the pads becoming ‘glazed’. All brake pads are constructed with an optimum operating temperature range. A good road pad that would be well suited to commuting to and from work or in start-stop traffic would have a low operating temperature (approx. 0-300 degrees Celsius). Performance orientated pads operate around the 400-800 degrees Celsius range, while dedicated race pads operate from 1000 degrees Celsius and up.
When a brake pad is forced to work beyond its ideal temperature range, this can lead to glazing. The brake pads material begins to break down and crystallise or harden. This results in a surface of very similar hardness and very low friction coefficient contacting each other, producing that same squealing noise. Performance brake pads are typically made of a different compound with a higher friction coefficient. This is why they are prone to squealing at low temperatures and are known for being harsh on brake discs.
During this glazing process, the brake pads friction material can break down causing the friction material to adhere to the discs surface. This results in a pulsating brake pedal when slowing from speed as the discs typically flat surface now has high and low spots. Contrary to popular belief this is a common cause of brake run out, and as long as your discs are not below their specified minimum thickness they can be machined or cleaned to rectify this.
A less common cause of brake squeal (although not uncommon) is when small stones/contaminants become stuck between the brake pad and disc. It’s easily fixed by quickly removing the pads and making sure they are free of grit. However, if you leave it unattended, this can result in the stone/contaminant cutting a groove into your disc as it pushes into the disc itself.
So there you have it. An in-depth look into the reasons why your brakes may be squeaking. Think it might be time for a tune-up? Head on over to Spares Box and check out our range of brakes and our Mid-Year Mega Sale! Saving up to 20% off!
Brembo brakes are world-renowned. With roots in the Italian city of Bergamo, Brembo are the holy grail of the braking universe – a brand that is the most recognisable, and highly respected. Pioneers of quality braking engineering, they have forged a hugely loyal base of admirers from every pocket of the planet. So if you’re investing in a piece of superior engineering, suitable for the most sought-after vehicles on earth, you don’t want to feel like you’re missing out. You want to get the absolute best out of those brakes, right? One crucial way of ensuring your brakes are prepared for their new environment is to bed them in.
Bedding in Brembo Brakes: What’s the Point?
When you fit Brembo brake pads, the first few applications of the brakes aren’t going to result in stopping power that will leave you lifting your jaw off the floor. Until they are bedded, brakes simply do not work as well as they should.
The purpose of bedding in your brakes is to have the rotor compatible with the pads, creating a stable transfer film that allows optimum friction over long periods. This is achieved through temperature, rubbing speed and line pressure, which allows an even layer of brake pad material to form on the rubbing surface of the rotor disc.
The rotor is heat treated, which eliminates any shock in the rotor. This heat also burns off moisture from the resin at the pad’s surface, avoiding the dreaded “green fade”. This phenomenon is where resin evaporates at the high temperatures involved in heavy braking and the pressurised gas that develops pulls the brake lining away from the disk, reducing friction. A loss of friction is no good thing.
Of course, the benefits of doing this has great overall results. Well-performed bedding greatly improves pedal feel, reduces brake judder and brake dust, and – importantly – lengthens pad and rotor life. Why pay for Brembo and miss out on all the good stuff?
Bedding in Brembo Brakes: How To
Bedding in is a complicated process that must be performed correctly. Doing it right does have incredible results though, so it’s pretty vital to follow the procedure closely.
- Reach 80km/h and feather your brakes a couple of times to raise their temperature – we don’t want to shock the rotors and pads.
- From 80km/h, make 8-10 hard near-stops in a row. It’s important to note that you never fully stop. You’re just firmly and quickly reducing your speed without grinding to a halt. At the end of each brake, quickly resume your 80km/h pace.
- After the last near-stop, come back up to speed and cruise for 15 minutes, using the brakes as rarely as possible to let them cool.
Seeing the Results
After, if performed correctly, there will be a blue tint and a grey film on each rotor face. The blue means the rotor has got to the break-in temperature, the grey is evidence the pad material has transferred to the surface of the rotor face. If you have that, you’re on to a winner! It’s now time live your life as the owner of fully-bedded Brembos.
Brake Shoes Explained
Brake Shoes are a major component of the Drum Brake System, one of the earliest braking systems to appear in automobiles. A Drum Brake is simply a large metal barrel or “Drum” that rotates with the wheel as part of the hub assembly. When you apply pressure to the brake pedal, hydraulic cylinders or pistons force the Brake Shoes (which sit internal to the drum) against the inner surface of the drum, creating friction and therefore slowing the vehicle. Brake Shoes often serve multiple purposes, not only as the main brakes, but as the vehicles handbrake as well. Vehicles often have a cable attached to one of the Shoes, which is levered by the handbrake within the car. Even nowadays a Drum Brake is often used within the conventional Disc Brake to act as the handbrake.
Contrary to popular belief, Drum Brakes are very effective due to their “self energising” action. As the first edge of the Brake Shoe is pushed into the spinning drum, the downward motion pulls the rest of the shoes surface against the drum. For this reason almost all Brake Shoes have what is known as a leading and a trailing edge, where the liner material is closer to the edge of the backing plate on one end than the other. This needs to be observed when replacing your Brake Shoes.
Drum Brakes vs. Disc Brakes
The achilles heel of the Drum Brake is its heat retention. The thick metal drum and shoes retain an enormous amount of heat, and with little to no airflow over the operating parts, they cool slowly. This is one big disadvantage in motorsport that lead to the eventual rise of the Disc Brake.
The other disadvantage is maintenance. While a conventional Disc Brake is self adjusting, Drum Brakes require adjusting to remain even. As the proximity of the shoe-to-drum can be adjusted on each corner, incorrect adjustment can lead to the car pulling left or right when braking. Uneven wear due to leaking cylinders or broken adjusters can lead to uneven adjustment and an ineffective handbrake. Similar to Disc Brakes, as Drum Brakes wear they leave behind a dust. This dust is allowed to collect within a Drum Brake causing harshness and noise.
Can I replace my Brake Shoes myself?
The replacement of Brake Shoes can be very tricky and tedious depending on your car. Your first time changing them will likely end in many curse words and throwing of spanners. They rely on a series of pins and high tensile springs to operate correctly, all of which need to go back exactly as they came out and with the correct adjustment. If you do decide to give it a go, leave yourself plenty of time. If you can get the assistance of a friend who has done it before we highly recommend it! Always wear goggles and hand protection, as the springs can be merciless when (and they will if you’re inexperienced) they fly off in any which direction at 100 miles per hour. Always do one side at a time so if you get stuck you have another side to reference. And just incase you can’t remember how the Brake Shoe went together, it pays to take a photo beforehand.
Brake pads have a wear indicator on them, which indicate that they’re wearing too thin to be safely used anymore. As the material on the brake pad slowly wears down, this indicator gradually becomes more exposed. When the brakes are applied, the indicator squeals against the brake disc rotor, creating the squeaky brakes most people are familiar with. Many european cars also have electronic sensors on them which will indicate on the dashboard that the brake pads need replacing.