Rules of Inspection
• Never evaluator the discipline of the brake pads using just one pad. Both pads and their thicknesses need to be inspected and documented.
• Never take rust or corrosion lightly. Corrosion on the caliper and pads is an indication the coating, plating or paint has failed and needs to be addressed. Corrosion can migrate to the area between the friction material and backing plate. Some brake pad manufacturers bond the friction material to the backing plate with adhesives. When the corrosion gets between the adhesive and friction material, delamination can occur. At best it can cause a noise problem – at worst, the corrosion can cause the friction material to separate and reduce the effective area of the brake pad. • Never ignore the template pins, boots or slides. It is rare a receive a caliper that has worn out the brake pads without tire or abasement happening to the guide pins or slides as well. As a rule, when the pads are replaced so should the hardware. • Never estimate life or thickness using percentages. It is impossible to predict the life left in a brake slog with a percentage. While most consumers might be able to understand a share, it is misleading and frequently inaccurate. In decree to accurately estimate the percentage of material break on a brake pad, you would first gear have to know how much friction material was present when the pad was raw. Every vehicle has a “minimum wear specification” for the brake pads, a number typically between two and three millimeters.
No matter the caliper design or vehicle, the desire result is to have both brake pads and both calipers on an axle wear at the lapp rate. If the pads have worn evenly, it is proof that pads, calipers and hardware have functioned properly. however, it ’ s not a undertake that they will operate the lapp way for the next hardening of pads. Always renew the hardware and service the guide pins .
Outer Pad Wear
Conditions that cause the out brake pad to wear at a higher rate than the inner pads are rare. This is why break sensors are rarely put on the out pad. Increased wear is typically caused by the outer pad continuing to ride on the rotor after the caliper piston retracts. This could be caused by sticky steer pins or slides. If the brake caliper is an pit piston design, out brake pad wear is an indication the out pistons have seized .
Inner Pad Wear
Inboard brake embroider wear is the most common brake pad wear radiation pattern. On a floating caliper brake system, it is normal for the inner to wear faster than the extinct – but this deviation should only be 2-3mm. More rapid inner pad wear can be caused by a seize caliper steer pivot or slides. When this happens, the piston is not float, and equalizing force out between the pads and the inner pad is doing all of the work. Inner pad tire can besides happen when the caliper piston is not returning to the rest side due to a break navy seal, damage or corrosion. It can besides be caused by a problem with the chief cylinder. To correct this kind of wear, take the same steps as fixing out embroider wear deoxyadenosine monophosphate well as inspecting the hydraulic brake system and the caliper for residual pressure and steer pin hole or piston boot damage, respectively. If the personal identification number holes or piston boot are corroded or damaged, they should be replaced.
Tapered Pad Wear
If the brake pad is shaped like a chock or tapered, it is a sign the caliper might have besides much movement or one side of the slog is seized in the bracket. For some calipers and vehicles, tapered wear is normal. In these cases, the manufacturer will have specifications for the taper wear. This kind of wear may be caused by improper slog initiation but the more likely perpetrator is careworn lead bowling pin bushings. besides, corrosion under the abuttment clip can cause one auricle of not move. The merely means to correct for taper wear in to make certain the hardware and caliper can apply the pads with peer wedge. Hardware kits are available to replace the bushings .
Cracking, Glazing or Lifted Edges on the Pads
There are multiple reasons why brake pads can overheat. The open may have a glistening airfoil and tied cracks but the wrong to the clash material goes deeper. When a bracken pad exceeds expected temperature ranges, the resins and bare-assed components can break down. This can change the coefficient of friction or even damage the chemical makeup and cohesion of the bracken diggings. If the friction material is bonded to the backing plate using only adhesive, the bond can be broken. It does not take driving down a mountain to overheat the brakes. Often, it is a seized caliper or a stuck parking brake that causes a pad to be toasted. In some cases, it is the fault of a low-quality friction material that was not adequately engineered for the application.
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mechanical attachment of the clash substantial can give an extra layer of safety. The mechanical fastening goes into the last 2mm to 4mm of the friction material. not only does mechanical attachment improve shear forte, but it besides gives a level of substantial that remains if the friction material that will not separate under extreme conditions .
A back plate can be bent as the result of any of respective conditions. • The bracken pad can become seized in the caliper bracket or slides due to corrosion. When the piston presses on the back of the launching pad, the force is not equal across the metallic element backing plate. • The friction fabric can become separated from the back plate and change the relationship between the rotor, backing plate and caliper piston. If the caliper is a two-piston float design, the pad can become flex and even cause a hydraulic failure. The independent perpetrator of friction material separation is typically corrosion. • If a substitution brake pad uses a low-quality support plate that is thinner than the original, it can bend and cause the friction material to separate from the back plate .
As stated before, corrosion of the caliper and pads is not normal. OEMs spend a fortune money on airfoil treatments to prevent rust. Over the past 20 years, OEMs have started to use plate and coatings to prevent corrosion on calipers, pads and even rotors. Why ? function of the return is to prevent customers seeing a rusty caliper and pads through a standard debase bicycle and not a emboss steel wheel. But, the main reason for fighting corrosion is to prevent noise complaints and extend the longevity of the brake components. If a replacement pad, caliper or even the hardware does not have the same level of corrosion prevention, the replacement interval becomes a lot shorter due to uneven pad wear or even worse. Some OEMs used a galvanize plat on the back plate to prevent corrosion. Unlike paint, this plating protects the interface between the back plate and friction material. But, for the two components to stay together, mechanical attachment is required. corrosion on the second plate can cause delamination and flush cause the ears to seize in the caliper bracket.
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Tips and Guidelines
When it comes time to order the substitution brake pads do your research. Since brake pads are the third most replace token on a fomite, there are many companies and lines competing for your occupation. Some applications are focused on the customer ’ second requirements for fleet and operation vehicles. besides, some replacement pads offer “ better than OE ” features that can reduce corrosion with better coatings and platings. extra features like complete hardware kits that utilize high-quality steel and elastomeric coatings can prevent the pads from seizing in the caliper and prevent noise problems during the integral life of the pad. If you have to replace the pads on your personal vehicle, use it as an opportunity to evaluate a brake embroider caller for yourself. If the pads and rotor have been worn past recommend levels, inspect the caliper ’ s piston boot and the piston. Once the piston has been out so far, it may not retract by rights ascribable to corrosion on the exposed piston. besides, The piston seal loses its flexibility as it ages. This will prevent the piston from returning to its rest status. This can cause the brakes to drag and increase pad wear. Some electronic brake distribution systems may have faster than normal rear brake pad wear rates. This is convention in some cases. The rationality for this wear is because the back brakes are used to control nose dive. If the wear is greater than expected, check for TSBs. Often, the OEM will issue new software for the hydraulic see module that solves the problem .