24/05/2011
Having your rear brakes decide to take an unscheduled holiday can be a rather alarming experience. If you find yourself in this predicament, the immediate priority is to ensure your safety and that of others. The first sensible step is to locate a secure spot to pull over and bring your vehicle to a complete stop. Once safely stationary, it’s advisable to disembark and conduct a preliminary visual inspection of the brake pads. If they appear to be completely worn down to the metal backing, then a replacement is almost certainly in order. However, if there’s still a discernible amount of pad material remaining, you might consider attempting to bleed the brake system. But there's considerably more to delve into regarding why your rear brakes might be failing and the crucial actions to take when you find yourself in such a precarious situation.
What Causes Your Rear Brakes To Fail?
The most prevalent culprit behind a complete or partial failure of your rear brakes is a leak within the braking system. Over the passage of time, brake fluid, which is absolutely essential for hydraulic braking, can gradually seep out from the brake lines. This insidious loss of fluid directly translates to a significant reduction in hydraulic pressure. The consequence of this pressure loss is often a spongy sensation when you apply the brake pedal, or in more severe cases, a complete inability for the brakes to engage effectively. Another significant contributor to rear brake malfunction is the inevitable wear and tear that affects all vehicle components. The brake pads (or shoes, in the case of drum brakes) are designed to wear down over time as they perform their duty of creating friction. When these components become excessively worn, their effectiveness in generating the necessary stopping power diminishes considerably. Furthermore, the braking surfaces themselves, whether they are drums or rotors, can also fall victim to wear and damage. Drums can become scored or glazed, while rotors can develop grooves or become warped due to excessive heat. When drums or rotors are in such a compromised state, it makes it exceedingly difficult for the brake pads or shoes to make proper, consistent contact, thereby severely impairing braking performance. If you notice that your rear brakes are not functioning as they should, it is of paramount importance to have them inspected by a qualified and experienced mechanic as soon as possible. Neglecting this could unfortunately lead to a serious accident.
2 Reasons Why Your Disc Brakes Don’t Work
While the general principles apply to both drum and disc brakes, disc brake systems have their own specific failure points. Firstly, as mentioned, worn brake pads are a common issue. These friction materials are designed to be sacrificial, wearing down with each application of the brakes. When they reach a minimum thickness, they simply cannot generate enough grip. Secondly, and often overlooked, is the condition of the brake caliper. The caliper houses the brake pads and contains a piston that pushes the pads against the rotor. If the caliper is seized, corroded, or its seals are leaking, it can prevent the piston from moving freely, or worse, cause a fluid leak, leading to a loss of hydraulic pressure and thus, ineffective braking. A malfunctioning caliper can significantly impact the performance of your disc brakes.
How You Should React When They Do
If your rear brakes fail while you are actively driving, the absolute most critical thing you can do is to remain calm and resist the urge to panic. Panicking can lead to rash decisions that could exacerbate the situation. Instead, focus on controlling the vehicle. You should attempt to pump the brake pedal slowly and steadily. This action can sometimes help build up residual pressure in the system. Crucially, avoid slamming on the brakes. Sudden, forceful application can cause the car to skid, potentially leading to a loss of control. If your vehicle is equipped with an emergency brake (also known as a handbrake or parking brake), this is the time to use it. Engage the emergency brake gradually and smoothly to help slow the vehicle down. Avoid a sudden, sharp pull, as this can also cause a skid. Once the car has slowed to a manageable speed, engage the parking brake fully to hold the vehicle stationary. Immediately shift the gear selector into the 'Park' position (if applicable) and activate your hazard warning lights to alert other road users to your predicament. Once the vehicle is safely stopped, it’s wise to get out and assess the situation, if it is safe to do so. If you are in a dangerous location, your priority is to get yourself and the vehicle to a safer spot if possible, or at the very least, ensure you are highly visible. If you have a mobile phone, call for roadside assistance or emergency services. If you don't have a phone or reception, you may need to try and flag down a passing motorist for assistance. Under no circumstances should you attempt to drive the vehicle if your rear brakes are not functioning correctly. Doing so poses an extreme risk to yourself and others. Hopefully, this guide has provided you with a clearer understanding of what to do if your rear brakes fail. Remember, it is always prudent to err on the side of caution. Having a qualified mechanic inspect your car promptly is the safest course of action. Do not attempt to drive if you have any doubts whatsoever about the condition of your brakes, as this could put you and innocent bystanders in considerable danger.
When You Need To Replace Them
When the time arrives that your rear brakes require replacement, it is absolutely vital that you use high-quality parts that are specifically designed for your particular make and model of vehicle. Using substandard or incompatible brake components can lead to further, more serious problems down the line, potentially compromising your safety. It is always best to consult with a qualified mechanic or an authorised dealership before undertaking any brake repairs or replacements. Furthermore, it is equally essential to ensure that your new rear brake components are compatible with your existing front brakes. Mixing and matching different types or brands of brake components can lead to uneven braking forces and a significant decrease in overall braking performance. This imbalance can make your vehicle unpredictable and more difficult to control, especially during emergency stops. Again, using defective or mismatched brake components can undoubtedly lead to further problems and potentially costly repairs in the future. If your brake pads are found to be excessively worn, they will undoubtedly need to be replaced. In addition to pads, the brake drums or rotors may also require replacement if they exhibit signs of damage, excessive wear, or warping. Depending on the severity of the issues identified, it might be possible to repair certain aspects of your rear braking system, or you may face the necessity of a complete replacement of the components.
How Do You Diagnose Rear Brake Problems?
Diagnosing rear brake problems typically involves a systematic approach. Begin by meticulously inspecting the brake pads. If they have worn down significantly, they will not be able to generate sufficient friction against the rotor or drum to effectively stop the car. Next, examine the rotors (or drums) for signs of wear. If they are grooved, unevenly worn, or show signs of bluing (indicating overheating), they may also need to be replaced. Another critical area to investigate is the possibility of a leak in the brake line. This can often be diagnosed by carefully checking all brake lines and connections for any visible signs of brake fluid leaks. A low brake fluid level in the reservoir can also be a strong indicator of a leak somewhere in the system. Finally, in some cases, the rear brakes might simply require an adjustment. For drum brake systems, this is often done by adjusting a star wheel within the brake assembly, which tightens or loosens the brake shoes. For disc brakes, while less common for routine adjustment, issues with the caliper mechanism might require specific attention. If you are unsure about performing these checks yourself, it is always best to consult a professional.
Front Brakes Work But Not Rear.
When your front brakes are functioning correctly, but the rear brakes are not engaging, this often points towards a specific set of issues. The most probable cause in this scenario is a leak in the brake line that specifically serves the rear braking system, running from the master cylinder to the rear wheels. This is generally considered a relatively straightforward repair for a competent mechanic. Once the leak is identified and properly repaired, the rear brakes should resume their normal function. In the interim, it is absolutely imperative that you exercise extreme caution when driving. With only the front brakes operating effectively, your vehicle's ability to stop will be significantly compromised. You must apply the front brakes gently and smoothly when slowing down, and be mentally prepared for substantially longer stopping distances. It is strongly advised to avoid driving in heavy traffic or on high-speed motorways or highways, where the reliable and immediate performance of both front and rear brakes is absolutely critical for safety. I hope this article has illuminated the potential causes of rear brake failures and provided you with actionable steps on how to address these issues promptly. The diagnostic steps outlined are generally straightforward and can often be performed in your own garage if you have the necessary tools and knowledge. Should you still have lingering questions about any aspect of this process, please feel free to leave your comments below; we're here to help.
FAQs
Q1: How quickly should I get my rear brakes checked if I suspect a problem?A1: If you suspect any issue with your rear brakes, it’s crucial to have them inspected by a qualified mechanic immediately. Driving with compromised brakes is extremely dangerous. Q2: Can I drive my car if only the front brakes are working?A2: While it might be technically possible for very short distances at low speeds, it is highly discouraged and dangerous. Your stopping distances will be significantly increased, and you risk losing control of the vehicle, especially in emergency situations. Q3: What are the signs of worn-out brake pads?A3: Common signs include a squealing or grinding noise when you apply the brakes, a longer stopping distance, and a spongy or soft brake pedal. Some brake pads also have a wear indicator that will scrape against the rotor when they are low. Q4: How much does it typically cost to repair rear brakes?A4: The cost can vary widely depending on the vehicle, the specific problem, and your location. Replacing worn brake pads might cost anywhere from £100 to £300, while more complex issues like caliper replacement or brake line repair could be significantly more. Q5: Is it safe to mix different brands of brake pads?A5: It is generally not recommended to mix different brands or types of brake pads or shoes, especially on the same axle. This can lead to uneven braking, premature wear, and reduced performance. It's best to use matching components.
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