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.

Safety

  • 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.

Dangerous!

This brake rotor has been very hot, and has been run with a worn out brake pad. The metal has been damaged!
This brake rotor has been very hot, and has been run with a worn out brake pad. The metal has been damaged!

To check your rotors.

Inspection:

  • 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.


Emergency braking.

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.


Warped discs.

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.

Very dangrous!

Cracked.

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.

The blue tinge in the metal is an indication of overheating. This disc needs machining or replacing, depending on it's remaining thickness after a cut.
The blue tinge in the metal is an indication of overheating. This disc needs machining or replacing, depending on it's remaining thickness after a cut.

Grooved.

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.


Wear.

Worn 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.

You can see the wear on the outside of this tyre. This indicates that the cars wheels are pointing in at the front, or "toed in" Under brakes the car will spin around backwards!
You can see the wear on the outside of this tyre. This indicates that the cars wheels are pointing in at the front, or "toed in" Under brakes the car will spin around backwards!

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.

This is a badly scored and worn disc. Dangerously lengthens stopping distance
This is a badly scored and worn disc. Dangerously lengthens stopping distance

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.

Disc pads

You can see the disc pads which are disposable here in good condition. You would need to remove the wheel to have this view.
You can see the disc pads which are disposable here in good condition. You would need to remove the wheel to have this view.

Worn disc pads

The top pad is new, the bottom one is completely worn out. If this happens to your brakes you have a wheel cylinder seized or other serious mechanical fault on that wheel brake. Inspect them all and have the brakes hydraulics rebuilt
The top pad is new, the bottom one is completely worn out. If this happens to your brakes you have a wheel cylinder seized or other serious mechanical fault on that wheel brake. Inspect them all and have the brakes hydraulics rebuilt

A view of a disc brake assembly

Note disc brake rotor is clean and dry. Click to enlarge all photos
Note disc brake rotor is clean and dry. Click to enlarge all photos

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.

Inspection:

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.

This used Ammco was old but in perfect condition after refurbishment
This used Ammco was old but in perfect condition after refurbishment

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 .

Brake lathes.

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.



Who repairs your brakes?

More by this Author


Comments 37 comments

VioletSun profile image

VioletSun 7 years ago from Oregon/ Name: Marie

Hi, Ernest: The warped discs paragraph, made it clear to me why the car that a friend drives sometimes starts and stops with an uneven feeling; had no idea! Unfortunately, I didn't learn to drive as I lived most of my life in New York where driving is not encouraged, but now I have to learn as I live in a part of the country where driving is must, and learning how a car works is a good idea.


James Agbogun profile image

James Agbogun 7 years ago

I wish i could sometimes fix some minor problems. Thanks for the Hub.


shanekruger profile image

shanekruger 7 years ago

Very Nice Hub buddy, Keep it Up


habee profile image

habee 7 years ago from Georgia

Thumbs up, E. Great info, even though it's mostly Greek to me. lol


shamelabboush profile image

shamelabboush 7 years ago

Though brakes are vital parts in the car, but it seems that some people around me don't pay attention to them. As for me , I always make sure to check them weekly to make sure they're ok bcz my life depends on them. Thanks.


earnestshub profile image

earnestshub 7 years ago from Melbourne Australia Author

Thank you all very much for reading.

VioletSun, I have another hub on driving you may wish to read as well.

Stick around James, I have been able to teach a lot of lay people the basics, and my mechanical hubs grow regularly as I find new ways to explain complexity simply.

Thanks for looking in habee and shanekruger.

shamelabboush Glad to hear you check your brake regularly... smart.


Jane@CM profile image

Jane@CM 7 years ago

So thankful that my husband is able to do these things. Great article for those that want to learn!


agvulpes profile image

agvulpes 7 years ago from Australia

earnestshub, great information about the brake repair industry, as you say I have seen many unqualified people doing repairs on car brakes.

Maybe you should also mention the over charging in the Brake Repair Industry as well?


earnestshub profile image

earnestshub 7 years ago from Melbourne Australia Author

Thanks Jane, so glad you have that inbuilt facility, er I mean husband!


earnestshub profile image

earnestshub 7 years ago from Melbourne Australia Author

Thank you agvulpes, I will take your sage advice and add it to the hub.


besttiffanyonline 7 years ago

The information obtained from this very helpful for me, thank you.mens tiffany necklaces


khmohsin profile image

khmohsin 7 years ago from London,UK

cool suggestions , good hub too.


Beth100 profile image

Beth100 7 years ago from Canada

Could have used this info about a month ago...now, I'm armed for the next round of brake repairs. :) Thanks Earnest!


earnestshub profile image

earnestshub 7 years ago from Melbourne Australia Author

Thanks Beth, I will be editing this and my other mechanical hubs to make them as easy to work with as possible, so it will be much improved.


Misha profile image

Misha 7 years ago from DC Area

I always do my brakes myself. Too much depends on them to outsource this. :)


earnestshub profile image

earnestshub 7 years ago from Melbourne Australia Author

Me too Misha.


aware profile image

aware 7 years ago from West Palm Beach Florida.

my brothers out of town . and my tires are squeaking. hope he gets back soon. lol .good info ty earnest.


earnestshub profile image

earnestshub 7 years ago from Melbourne Australia Author

Thanks for the comment aware.


Bovine Currency profile image

Bovine Currency 6 years ago

Great hub :)

I will view more of your car maintenance hubs. I have noticed over the years how unreliable many operators can be. I have a relatively new car, technically should still be under warranty but having worked in car sales and in big dealerships, also having mechanics friends, I would not even bother taking my car to a dealer, warranty or no warranty. I hardly spend a cent on my car anymore and it works well. I knew a little about grooving but I particularly like the second half of this hub.


earnestshub profile image

earnestshub 6 years ago from Melbourne Australia Author

Thanks BC, I will keep adding to the data.


PB_Smith profile image

PB_Smith 6 years ago from Southern California

A picture is worth a thousand words, and those pics are good at showing what to look for. I usually will replace the pads myself if the rotors are good and don't need turned. Is that wise or should I have them turned every time?

Drum brakes are a bit more of a pain though.

If a rotor is warped or a drum is out of round could that also cause the brake pedal to feel like it is "pulsing" or move up and down while braking? I noticed this on another car I had, but since the engine is blown I'm not worried about the brakes. :)

Just curious if that was another symptom, that is what I was told caused that "pulsing" of the pedal.


earnestshub profile image

earnestshub 6 years ago from Melbourne Australia Author

Thank you PB_Smith, yes pics do help don't they?. If there is no grooving and the rotor is not glazed it is usually fine to just replace the pads.

The pulsing can be a disc or drum that is warped.

Easy to check yourself. To chech drum brakes Jack the wheels up one at a time. put the handbrake on slightly and rotate by habd. You will find the tight spot if it has one. Now jack up the disc brake wheel, remove the wheel and put a small nail or even a piece of chalk against the rotor and revolve by hand. If the disc moves away from the marker it is warped. You will also see it with your eye.

Disc are usually easy to pick, most times you can just jack the wheel up and rotate it to find the tight spot. The pulsating brake pedal is a good indicator. I have seen a faulty ABS system cause pedal pulse, but rare.


Kosmo profile image

Kosmo 6 years ago from California

Lots of good information here. I usually get my brakes done at Midas. Is that a good place to take it? They actually seem honest there. What a concept! Incidentally, I'm thinking of writing a hub about how to buy a cheap new tire that lasts as long as the tread. Is it possible to find such a thing? Later!


earnestshub profile image

earnestshub 6 years ago from Melbourne Australia Author

Thanks Kosmo. I have used Midas myself and found it depends on which Midas you use. Some are great. Quick story about service places.

When repairing brake lathes for various workshops, I got to see the condition of the equipment they use to fix brakes.

One place the brake lathe was so bad I marked it as unusable! They continued to use it and ruined every set of disc rotors they did.


Jane Bovary profile image

Jane Bovary 6 years ago from The Fatal Shore

Oh my...my brakes need doing at the moment, they're shuddering when I roll up to the lights. Last time I had them done at Kmart, just for convenience. Do they know what they're doing? I guess it's like Midas...depends on which one.

Thanks for the info


saddlerider1 profile image

saddlerider1 6 years ago

I just had my SUV in for a check up for brakes. They told me I need front brake pads and rotors, that's standard fare. But they also told me my driver's side front wheel bearing needs replacing? What causes a wheel bearing to need replacing? I notice my brake pedal is pulsing as well, is this the cause of the worn bearing? How long and safe is it to drive with a front bearing problem? Great information by the way.


earnestshub profile image

earnestshub 6 years ago from Melbourne Australia Author

Jane KMart are usually OK, although I found one of their branches had a crook brake lathe that would never do the job, so as you suggest, it does depend on the branch. If they did it last time and it shudders, I would take it somewhere else, because unless you have a worn suspension component or loose or worn wheel bearings, I would blame the brake lathe they used, and if they do not service it properly your brakes won't last long between repairs.

When servicing brake lathes for brake repairers I found about one in 5 brake lathes too worn in the tools or in urgent need of repairs, and the machine could not do a good job in this condition..


earnestshub profile image

earnestshub 6 years ago from Melbourne Australia Author

saddlerider, I would check the rotors from the outside yourself as I have suggested in this hub and compare it with the pics I have. The pulsing will be a warped disc or a rusted spot from sitting un-used. The wheel bearing that is worn should be the one on the curb side. It wears first because it travels on the rough surface at the road's edge.

The reason the pulsing will not be likely to be caused by the wheel bearing is that the wheel is "carried" by the disc in a central location when the brakes are on. If you want to check it right out before trusting them, email me or just tell me the make and model in the comments. I know most make and model's idiosyncrasies.

By the way, I usually check both wheel bearings if one side is worn. The other side will be almost worn out too. Wheel bearings do a very high mileage (unless design faults) and the most common reason for failure is incorrect tension on the bearing retainer nut, or the bearing has been poorly packed with grease. I pack them very densly, some do not know and just put grease on the bearing. It must be packed with grease to last. I hope this helps. A badly worn bearing will make a lot of noise too.


Jane Bovary profile image

Jane Bovary 6 years ago from The Fatal Shore

Hey thanks Earnest. Advice noted.


saddlerider1 profile image

saddlerider1 6 years ago

Hi Earnest thank you for the advice. My vehicle is a Pontiac Aztek, year 2003. There is no noise coming from either front wheel, the only thing happening is my brake pedal is pulsing. They told me I need a new front bearing and front brakes. I believe them about the brakes, not sure about the bearing. My ABS light stays on and they told me it will go off after they replace the bearing, however I took it to Midas and they told me both abs harnesses need replacing as well as a front brake job, but many people who don't like abs don't bother to have the harness's replaced they told me so I did not have them do it, yet this other garage didn't even bring up the harness situation,they told me I needed a new bearing and brakes. I am confused, maybe I need a third opinion. lol


earnestshub profile image

earnestshub 6 years ago from Melbourne Australia Author

You are most welcome Jane. I hope whoever you get to do the work does a good job this time.


earnestshub profile image

earnestshub 6 years ago from Melbourne Australia Author

saddlerider1, I know these quite well although we do not have an equivalent in Australia, there have been a few imported by private owners.

Unfortunately they have common electrical and mechanical problems.

ABS brake problems can be triggered by loose wheel bearings on this model. They apparently eat wheel bearings which are unbelievably expensive to replace.

Cylinder head gasket failure is common, although in my opinion this is caused by allowing the engine to overheat because they develop hose problems and leak where they join the radiator, air-conditioner failure is common if left unused in winter, but this is not unique, as if you let the compressor remain unused they put a dent in the seal from sitting in one place as do all air conditioner compressors of this type.

I would be massively careful about who does the work. Those who do not know assume the recurring design faults mentioned, which is not always the case. Feel free to give me mileage and history if you like and I will be able to narrow it down. Lots of quotes and a firm quote to repair would be my approach with this model.

I can see you are smart from your comments, so trust your own judgement would be a good idea once we work out the likelihood of the problems origins.

Good luck my friend, and feel free to contact whenever you like. I am here to help. I know these were a bargain and have a strong following despite their problems.

The harness replacement sounds downright strange, unless you have had other electrical problems or it looks badly sulphated where it plugs in I would be amazed you would need to replace them. A strange but related question. Does your fuel gauge work OK? As a money saving exercise I would check the discs for warping yourself as mentioned in this hub. If the problem is a warped disc it will be a slow pulse, if ABS a lot faster.


Shannon Paulk 6 years ago

Make sure you know the warranty on your manufacturers brakes or your new brakes if you install new ones. Getting extra coverage from companies like warrantyheadquarters.com can really save you a ton if something happens.


Nicky Smart profile image

Nicky Smart 5 years ago from United Kingdom

thanks Earnest. Advice noted.


earnestshub profile image

earnestshub 5 years ago from Melbourne Australia Author

And thank you Nicky, for your comment.


charlied 4 years ago

I just had my rear brake cylinders and shoes done on my 2001 Hyundai Elantra. The brakes work fine on the ride home but when I stopped and put on the emergency brake it is suddenly not working. When my mechanic was starting the job he took the tire off and was hammering on the drum to get it loose. After a few tries he asked me if the emergency brake was on and I said yes and he told me to take it off. Could him hitting the drum with e-brake on have caused this problem?


Inthebag57 2 years ago

Hi my brakes on 2000 Mitsubishi Montero sport are working, no squeaking or grinding, They just smelled like they are burning, ever since I braked really hard one time. I've been told I need two new front tires because the treads are shot. Could this be the problem?

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