Ask the mechanic : How do I tell that my brakes are worn-out?

You need to look out for either squeaking or rattling noise when you brake

Hello Paul, Thank you for this service; it is really an amazing thing. Now my question is; how do I tell that my brakes are worn-out or at what mileage do I need to change them?
Ronny Paul Kaweesa.
Hello Ronny, brakes are one of the very important tools we use to control a vehicle in motion and ensure our safety. Brakes slow or stop a vehicle in motion using contact friction.
The condition and size (width) of the brake friction material is crucial in determining how promptly and effectively our brakes can work. On most vehicles, there is an emergency parking brake used to prevent the car from rolling off when parked and the foot brake used to stop the vehicle when in motion.
Most vehicles use brake pads on front and rear wheels while others employ a combination of brake pads in front and brake callipers (shoes) at the back. The brakes work as part of a hydro mechanical system which uses charged hydraulic fluid pressure from the brake master cylinder and wheel brake cylinders to actuate piston plungers in brake calipers with brake pads or shoes. Therefore, when assessing the working condition of your car brakes, you should also consider the condition of the brake hydraulic system. When your brakes are worn-out, you can tell by observing their reduced performance, detecting different noises from the brakes or observing warning lights on your dashboard.
While driving you can tell that your brakes are worn-out or need attention when you experience increased braking distance whenever you apply the brakes. When your brake pedal starts to travel closer to the floor whenever you brake, it is a sign that the brake pads or shoes are worn out. Soft, spongy or hard brake pedal travel is also a sign of a break-down or leakage of the brake hydraulic and vacuum systems (master cylinder, wheel cylinder or brake fluid lines).
Squeaking or rattling noise when you brake is another sign of wear and tear of the brake pads and the friction rotors which they first engage to create frictional contact. Most post 1990 vehicles have warning lights on the dashboard or messages delivered on a message centre which will alert you about break pad wear or a leakage of the brake hydraulic system.
Routine inspection of the brake system often relies on the power of observation by your mechanic. Often this involves raising the car and taking off the wheels. A bonnet check should consider an unexplained drop of brake fluid level as a possible indicator that brake pad width has reduced.
A visual inspection of the brake pads can be used to determine their condition depending on their pad width and surface of friction material.

Dear Paul, I like your responses to our car problems. I have a Mazda MPV 97 diesel 2.5cc engine. The steering rack leaks, so I just have to keep refilling. I recently checked out Amazon and saw a fluid on sale (Lucas Power Steering Stop Leak). Have you heard about it or used it before? Was the result satisfactory if used?

Mr Kasule, the Lucas power steering fluid stop leak is a renowned solution for plugging steering leaks. It’s actually quite popular with DIY (Do it Yourself) motorists in the UK and North America. It works as a temporary reprieve from the heart wrenching cost of replacing your leaking steering rack assembly, steering box or steering pump.
I have not used it yet. I think that stop leak solutions must have a thicker fluid base with some kind of chemical coagulant (thickener). Whilst this product may stop a leak in the steering, it will affect the steering performance overtime.
If the replacement steering rack, steering box, pinion or seals are available it is better to replace them with new parts. In your case the Mazda steering rack or steering box replacement parts may not be readily available in Kampala. This may warrant you to use the stop leak solution until a more permanent solution emerges.

Hi Paul, I have a Pajero io GDI manual, Engine 1830 CC. Of recent, fuel consumption has increased to 9km per litre from 12km per litre. Where can I get good assessment from?

Hello Joab, your Pajero i.o needs a routine engine inspection which any reasonable mechanic near you can carry out. Sudden increase in the fuel consumption of an internal combustion engine is often due to factors which affect the emission system.
The technician should check the spark plugs for signs of electrode wear or poor burning of fuel. The air filter should be dusted or replaced if found very dirty. The air intake system should be checked for air leaks and the throttle potentiometer checked to confirm that the throttle valve moves freely.
Ask the mechanic to evaluate the performance of the fuel injectors, oxygen sensor and mass air flow sensor using a diagnostic computer just in case one of them is faulty.
Faulty sensors can cause poor fuel economy. Remember that regular car maintenance regime, choice of genuine spare parts, condition of tyres, use of cleaner additivated lubricants and fuels as well as your driving style will also affect your Pajero’s fuel economy.

Hello Paul, my name is Chris. For the past two days I have had trouble starting my Ford Ranger XLT in the mornings when it’s cold. I turn the ignition key on and off three to four times then it will start. But previously I used to do that only once for 10 seconds. Could the issue be with the Heater plugs?

Hi Chris, modern diesel engines usually require shorter heater (glow) plug heating cycles than the older ones. When you need to give your diesel engine glow plugs three to four heating cycles before they can start your engine then you need to consider replacing them.
A simple test by a technician in a garage can confirm whether the glow plugs and glow plug relay (timer switch) work well.
However if you have replaced the glow plugs within the last two years and the glow plug system (plugs and relay) responds well to the above tests in the garage you could consider inspecting or replacing the fuel filter in case of ingestion of contaminated fuel.

Ask the mechanic
By Paul Kaganzi
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