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A d v a n c e d   A u t o   M a i n t e n a n c e




 

Inspecting the braking system...


Every twelve months, inspect the thickness of all of the brake pads and/or brake shoes, as well as the condition of all of the flexible brake hoses and metal brake lines by cracking the wheel nuts, jacking the entire vehicle up, supporting it on axle stands and removing the wheels.


Replace brake pads and/or brake shoes with friction material thicknesses less than the minimum required...

The thickness of the friction material remaining on each of the brake pads and/or brake shoes should be measured and recorded.  Brake pads and/or brake shoes with friction material thicknesses less than the minimum thicknesses specified in the workshop manual for the vehicle, or less than 1mm in the absence of this information, should be replaced with new brake pads and/or brake shoes.  Failure to replace brake pads and/or brake shoes whose friction material thicknesses have worn down past the minimum will result in the brake discs and/or brake drums being scored and damaged when the brake pads and/or brake shoes wear down to their metal backing plates.  The sound of metal grinding against brake discs and/or brake drums is not a pleasant sound.  This kind of damage requires that the brake discs and/or brake drums be machined to trueness or replaced altogether if the scoring is too deep to be rectified.


Replace the disc brake pads and the brake shoes in left and right pairs…

Note that it’s very important to replace the brake pads or brake shoes on both of the left and right front wheels together or on both of the left and right rear wheels together.  Replacing the brake pads or brake shoe on only one wheel on one side of the vehicle while leaving the other old brake pads or old brake shoes on the other side of the vehicle can seriously impede the handling and safety of the vehicle when braking.  Therefore, if the brake pads or brake shoes of the wheel on one side of the vehicle are worn below the minimum thickness of friction material as specified in the workshop manual for the vehicle, or below 1mm of friction material in the absence of this information, then the brake pads or brake shoes of the wheel on the other side of the vehicle will have to be replaced as well, irrespective of whether they have worn down past the minimum thickness of friction material or not.


Inspect the condition of the flexible brake hoses…

The condition of all flexible brake hoses should be carefully inspected. The flexible brake hoses are safety critical components and should be replaced as quickly as possible if they show any signs of cracking or any other damage, which could easily lead to brake fluid leakage, catastrophic brake failure and possible resulting injury or even loss of life.  By bending them in different directions, you’ll be able to see whether they’ve developed any cracks or any other damage.  It may be necessary to clean them first with water or brake cleaner before you can inspect them properly.  Do not use any hydrocarbon-based solvent such as kerosene to clean them which can easily impede the safety and performance of the braking system if the brake pads and/or brake shoes are contaminated by the hydrocarbon-based solvent.


Inspect the condition of the metal brake lines...

The condition of all metal brake lines should be carefully inspected for signs of corrosion, leakage or any other damage.  The metal brake lines are safety critical components and should be replaced as quickly as possible if they show any signs of damage.


Hose the underbody of the vehicle while inspecting the brakes to save time…

If desired, in order to save time, the procedure of inspecting the brake pads and/or brake shoes, as well as the condition of the brake hoses and metal brake lines, can be combined with the procedure of hosing the underbody in order to remove the accumulation of dirt and grime and to minimise the chance of the underbody suffering from corrosion, as described in section titled, Vehicle Body Cleaning and Waxing.

It’s very important to hose the underbody only when the vehicle is cold and hasn’t been driven for several hours in order to avoid damaging the exhaust system, engine, transmission, differential or any other metal components.  If the above parts of the vehicle are hot or even warm, the cooling effect of the water from the hose can cause the section of the metal component being hosed to cool and contract more quickly than other sections of the same component which can result in the component actually cracking.  This is expensive, debilitating and discouraging damage which is best avoided.  The best time to hose the underbody of the vehicle is in the morning when the vehicle hasn’t been driven since the previous day.





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Copyright 2016 Andrew Mackinnon.  All rights reserved.