- Car Care & Maintenance
Worn Auto disc brake repairs.
How to tell if your brakes are worn?
Your brakes, tyres or steering alignment must all be in good condition to stop without skidding especially in the wet. Something is wrong if your car does not steer straight when braking hard, and consider this. Brakes that don't work properly when you need to brake hard are very dangerous, as emergency stops are just that. Emergencies .
Does your car skid in the wet when you brake hard?
Many drivers take their lives in their own hands by not knowing how well their car will stop in a situation that is critical, such as a child running on to the road in front of their car. After all, how often do you need to brake really hard?
Auto repairs can be expensive, especially brakes and suspension so if we don't know anything about our cars we have to trust the auto repairs guy to keep us safe and spend our money for us. Never a good idea unless you know a few basic things about brakes in my opinion!
If you know how to inspect your own brakes before your next service you can make sure you are not overcharged and that your brakes have been repaired properly.
- Some, but not all cars have ABS brakes which works to stop the tires skidding when you brake too hard for the tires to grip. ABS and other brake and steering assistance are part of a modern car's brakes. They are fitted with warning systems. These warning systems can and do fail making it is easy to ignore your brakes until they are no longer safe.
- If tyres are cheap, hard or worn the brakes will not stop a car properly in any circumstances, so ensure your car has good tire grip by fitting good quality tires designed for your car make and model.
A perfect disc rotor.
Simple disc brake Inspection
Inspect your disc brake rotors regularly. It's as easy as walking around your car!
In a few minutes you will know how to spot a problem and get preventative maintenance done to prevent more expensive or risky problems developing.
Brake repair costs can be greatly reduced by you having the knowledge of proper servicing and keeping the wearing surfaces in good condition is essential for full braking power in an emergency stop, so ... take a look yourself you may spot a problem.
To check your rotors.
- walk around your vehicle and look at the wheels. They are the round things the tyre fits around!
- Look through the middle of the wheel. See that shiny dinner plate sized thingy on the inside? That is your disc rotor and they are always on the front brakes.
* Most good light vehicles have disc rotors on all four wheels.
Stopping in an emergency is of course always dangerous, but if brakes are worn the outcome can be devastating, please check your brakes now! It may save your life or someone else's!
That one time you really need to stop good brakes save lives!
It takes less than a minute to inspect your brake rotors and ensure that they are in good basic working condition,
Apart from invisible fractures, which usually show up after accident damage, this simple inspection allows you to see obvious wear and damage.
Here is what to look for when you inspect your brakes and disc rotors in simple terms with a photo of what your discs should look like when in top condition.
The photo shows a disc rotor in good order.
When brakes are used hard they can overheat and warp a brake disc. Here is how to detect a warped disc.
When you are rolling to a stop gently with light brake pressure the car seem to stop unevenly resulting in your head going backwards and forward as the warped disc gives a stop start feel to slowing down.
The pedal will move up and down under your foot, slowly when going slow, and vibrating at higher speeds.
Please look through the comments to see if I have already answered your question. Feel free to ask me anything about your brakes or anything else about your car.
This is really serious, the vehicle should not be driven at all. This disc and probably the other disc/s will need replacement, as well as the components that caused the problem, which is likely to be all the wheel brake cylinders.
If the problem was caused by driving with totally worn out disc pads which have caused extreme heat, wheel cylinders will be in need of replacement still, as the rubbers would have been too hot to survive..
This disc is grooved and glazed.
Disc rotors should be smooth without any noticeable grooving. Grooving causes the disc rotors to run hot, brake unevenly and fade.
If your discs are grooved they are likely to fade or even fail when used down long hills or when towing a heavy caravan, trailer or horse-float etc.
The brakes will also be near useless in rain, ice and snow.
discs cause overheating which can result in total brake failure. It can
also force the grease out of the wheel bearings which can destroy your disc rotor
hub bearing surface. This can be dangerous and expensive to
replace, especially if it is made in one piece.
No matter how
sophisticated your car's braking system, it is only going to stop your
vehicle by the pressure exerted on the disc pads when pressed hard
against both sides of the rotor when you apply the brakes, so if the
disc pads or rotors are worn braking capacity is reduced, and your
car's brake assistance systems face real limitations in controlling
your vehicle in an emergency stop.
Tire wear and braking:
Never forget to check for tire wear as worn tires cannot grip the road, so braking will make the tires skid and the car will not stop quickly or straight on the road.
Wheel alignment toe-in.
Wheel alignment and braking.
Even if your brakes are perfect, bad wheel alignment will cause your car to steer in one direction or the other under brakes, making it very dangerous to apply brakes hard.
Signs that your wheels need aligning.
- The car steers to left or right when the steering wheel is allowed to travel freely on the highway.
- The tires squeal excessively when going around a roundabout at low speed.
- The steering wheel spokes are not in line when the cars wheels are pointing straight ahead.
- The tires are worn more on one side of the tread than the other.(As pictured above)
All these signs indicate that your wheel alignment is out far enough to be dangerous when braking from speed.
Worn disc brake rotor.
A disc brake rotor that looks grooved like this needs machining.The brown rusty color of this caste iron disc is normal, the blue color on the wear surface is not.... it indicates that the brakes have been overheated!
NB: If one disc is like this and the other one on the other side looks OK you may have wheel cylinder component failure and the car should not be driven except carefully to the repairer.
A disc brake rotor in this condition is often the result of heavy use with already tired brakes.
The handbrake operates on the rear discs on many models, and if the handbrake is left on while driving this sort of damage can happen quickly to the rear discs.
Normally it is the front brakes that wear fastest and it is not uncommon to do the fronts several times before the rear is in need of repair.
Worn disc pads
A view of a disc brake assembly
Worn disc pads
If you can remove your wheel to change a flat you can do a pretty thorough brake inspection yourself in about half an hour just using your car's jack in the driveway.
A smart thing to do on a lazy weekend.
When you remove the wheel you will see the disc rotor, and the brake calliper with the brake pads in it that you could not see clearly before removing the wheel.
This is the part that squeezes the pads against the rotor to apply the brakes.
There should be no oil or grease around this area it must be bone dry! If you see dust that looks dark and wet or even damp anywhere in this region you have a wheel bearing that is dying or a hydraulic leak coming from worn calliper seals or piston and you will need to rebuild all the callipers.
If your brakes have been cared for and the car is not quite old it is rare to have brake calliper failure.
Never have one repaired on it's own unless the other side was recently repaired separately. The other one behaving done the same amount of braking is likely to fail soon also.
Rotor calipers showing disc pads.
This is similar to what you see when you remove the wheel of your car.
This disc is ventilated. You are looking down on the assembly, so it is easy to see the disc pads.
These disc pads are nice and thick with plenty of wear left in them. Regular disc pad replacement is essential to avoid rotor damage.
Ammco 4000 brake lathe.
FMC/John Bean 600 series.
As a supplier of automotive workshop equipment, I know that many workshops don't know enough about all types of brakes to make informed decisions but many will do the job anyway!
Some dealers contract the work out to brake specialists, who often cut corners and consequentially endanger your family by either bad workmanship when re-surfacing your disc rotors, not replacing worn hydraulic seals or fitting sub-standard parts.
Braking systems on newer cars can deteriorate quickly, sometimes within a few months as wear and lack of preventative maintenance take their toll on disc brake rotor surfaces and brake pad wear.
Harsh driving, dusty roads and bad weather can combine with some vehicle brake design to result in brakes losing effectiveness earlier than you may expect. Some brakes designs that are meant to provide more powerful brakes use softer wear surfaces which can wear out quickly.
Brake disc rotors can become damaged without the driver knowing, as all may appear normal until an emergency stop is needed.
the signs of disc pads or disc rotors being prematurely worn, especially if the car is pretty new or still under warranty is disconcerting to the average motorist, but is usually caused by soft brake pads and dirty wet road grime cutting into the pads or other severe road conditions .
The brake lathe is a precision machines that cuts a new surface on your disc rotors and must be 100% accurate to make your brakes perform properly. Some times they are not.
Some brake lathes in older shops are not kept in top condition as they must be to do a perfect brake rotor machining job.
I reconditioned and repaired these machines and was disgusted at the poor standards applied by many operators who were often poorly trained. I also saw major brake places using inaccurate machines.
Get the provider right and you can halve your machining costs. A well machined disc will outlast an inaccurately machined one by a large margin.
There are two machines that do an exceptional job of disc resurfacing.
The John Bean FMC has a long history as a top quality brake lathe.
Ammco brake lathes.
West and others make good brake lathes but these two models will run accurately for 40 years without major repairs and can be set up to register +- 0 in run out for those who understand engineering tolerances this is pretty accurate when you are measuring 1000 thousandths of an inch with a dial gauge.
Do it yourself disc pad replacement
- Video 2
Brake repair video 1
- Check or Remove Your Lug Bolts
You should check the tightness of the lug bolts on all four wheels on a regular basis. If you have had any work done on the car, be sure to double check after 10 or 20 miles. Properly checking them will make your car safe.
- Brakes - Brake Pad Replacement - Replacing Your Brake Pads
Your brakes have been screaming at you for a week and you know it's time to change your brake pads. Why sit in a cramped waiting room drinking foul coffee and watching Fox News? You could be in your driveway doing the brake job yourself. You'll save