How do I know when to do the brakes?
Posted by 00Spiff@reddit | askcarguys | View on Reddit | 35 comments
Hello everyone. This might sound stupid but I'm trying to get into doing car work myself and I have to do a front wheel hub bearing on my car. In the process I'm thinking of doing the brakes too. I got the car with 68,000 as a 16 year old, it's at 97,500 now and I'm fairly confident we've never done the brakes. How do I know when to do rotors vs just pads? I've also never heard any squeaking though. While I'm here I'll also ask what I should plan to do at 100,000 miles. I know the timing belt needs to be done but I'll have a shop do that. Should I do spark plugs, coils, anything else? Thanks for the help. It's a 2012 Kia Sorento 2.4 in case that changes anything.
Low_Living4532@reddit
How thin are the pads? How scored are the rotors? How much rust is on the calipers? Are rotors too thin? Look at your flexible btake hoses, are they full of cracks?
Blu_yello_husky@reddit
You very rarely ever need rotors unless you run the pads down to bare metal and it ruins the rotor. I have a car thats over 50 years old with the original rotors.
As for pads, take the wheel off and see if you can fit a standard size no.2 pencil eraser between the rotor and the pad material. If it doesnt fit, you should replace the rotors. Some cars also have squealers on the pads that will make a high pitched screeching sound when you hit the brakes to let you know your brakes are getting close, but I wouldn't advise you go off of this, because not all cars have it for starters, but sometimes even cars that do have it, itll squeal when the brakes arent close at all. Its smarter to use the pencil eraser method. They also sell brake pad depth gauges at auto parts stores so you can be more precise than a pencil eraser if you desire.
No_Geologist_3690@reddit
The rotors of today don’t often take machining well without issues, which is why it’s better to replace.
Professionals aren’t checking brake pads with a pencil eraser.
Blu_yello_husky@reddit
OP isnt a professional. I chose a common household object that most people will have in order to avoid confusion.
No_Geologist_3690@reddit
Or they could buy an $8 measuring device to properly check it.
Blu_yello_husky@reddit
When I comment on posts in this sub, i am operating under the assumption the OP knows less about cars than the teens that work at taco bell. Trusting that someone like that can use a depth gauge or even know what to buy, is pretty bold. A pencil eraser is about 6mm, which is at the low end of acceptable wear for brake pads. So if you cant fit the eraser in there, you probably need brakes. There's no need to have the tool if you can achieve the same with a pencil thats been sitting in your office desk drawer for 10 years.
No_Geologist_3690@reddit
Ok well you’re providing the guy bad advice. The $8 brake pad measuring devices are colour coded and idiot proof.
Blu_yello_husky@reddit
I said its at the low end of normal. 6mm is the first yellow tile on the gauge. I dont recommend brakes to customers until 4mm. 3mm is in the red. So if you have a 6mm pencil eraser, and it wont fit between the pad and rotor, that means your pads are at at least 5 or lower, and its time to consider replacing pads.
Its not bad advice, you just have poor reading comprehension. Its not my fault you cant figure out how to improvise without the proper tools.
Lastly, if you go back to my original comment, I DID say OP could go to the auto parts store and buy the gauge, its just not a requirement to check your pad depth. I dont even need the gauge anymore, I do it visually. After doing literally THOUSANDS of brake jobs, you get a feel for where pads should and shouldnt be.
EnvironmentFun4136@reddit
These people are ridiculous about rotors. I don’t change rotors unless they’re warped. You aren’t going to wear through one lmao. The way you tell if they’re warped, is braking at highway speeds and if the car vibrates while breaking they’re warped. Don’t waste your money otherwise.
crusty_mcnipples@reddit
I did brakes, rotors, spark plugs on my daughter's 2015 Hyundai sonata for less than $120 last year. Buy parts online.
SpaceCat72@reddit
Squeeler tabs, no noise? Gotta pull the wheels and look at clearances. Also diff between bonded and riveted pads. Send pics. Pull the drums if it has them
antidavid@reddit
You just need to inspect the pads. If they look close to the metal you’ll want to replace them. And you should pretty much always replace the rotors unless you know of a shop that resurfaces them.
As for 100k you need to look up your vehicles maintenance schedule. Usually when you do a timing belt you’d also do plugs and other maintenance items like your air filters etc.
Tobazz@reddit
Almost no shop resurfaces any more, most rotors don’t have enough material to still be safe. My shop recommends replacing pads at about 4mm
antidavid@reddit
This. They’re basically throw away these days and a set of rotors for most econo cars can be had for about a 100 bucks. I’d imagine a resurface is about the same.
But I will say for op don’t buy drilled rotors especially cheap ones. There have been instances of them cracking under normal operation.
nueroticalyme@reddit
Its still economical for diy. Most napa and orielly will turn rotors for $25 ea for cars and $30ea for trucks. The oem rotors are usually much better quality than most of the aftermarket parts and have plenty of material to cut once or twice.
LowEmergencyCaptain@reddit
Good call on just swapping the rotors too. I have found it really difficult to find a shop willing to resurface mine the last several times.
00Spiff@reddit (OP)
Good advice, thank you.
iHaveLotsofCats94@reddit
Just a note as well, there is a minimum thickness for those rotors that should be stamped into the rotor itself. You can measure the rotors with a caliper to see if they can be resurfaced, but i would just replace them regardless. Resurfacing increases the chances of warping in the future since you're taking material away when you resurface.
Always inspect brakes if you're curious. It's easy to do
Talentless_Cooking@reddit
There's a little metal wire nickname screamer, you know the sound when you hear it, that's when you go for brakes.
H0SS_AGAINST@reddit
Pad inspection.
Also, many have squealers but those like to rust away and fall off long before they're actually useful.
Just do pads and rotors together, rotors are so cheap it's not worth your time getting them turned. Plus you can get coated top hats which is definitely recommended if you live where they salt the roads.
TheWhogg@reddit
Does your car have break pad wear sensors? If not, replace when ONE of the pads (which may be inside) is 3mm. That’s very small. You might be able to use a cheap endoscope to photograph. Wheel off is best practice for inspecting brakes.
Everything fluid / filter / equivalent this is serviceable is a service item. If manufacturer says lifetime coolant or transmission / diff, find a proxy from a manufacturer who recommends their regular replacement. And do engine oil well before officially “due” by miles - I’m more tolerant by months.
hemibearcuda@reddit
An old general rule we used in the industry 40 years ago was this. If the brake material is equal in thickness or less than the metal backing plate it's fastneded to, then it's time to replace them.
The sintered material is the part of the brake that contacts the rotor. It's the part that wears away and leaves black dust on your wheels. It can be bonded or riveted. These days most are bonded or "glued". Inspect the thickness of it.
It's a good practice to resurface or "turn" the rotors when installing new pads. It helps with the braking performance and life of the new brakes. In the old days we turned them on a brake lathe.
Many auto parts stores offer this service. I've learned these days, it's sometimes cheaper or similar in costs just to replace the rotors depending on the model. Research this.
Take your time, do one side at a time. That way you have a reference if you forget how something is assembled.
Do not let your caliper hang by the brake hose. Tie it up with zip ties or safety wire while you work.
Good luck.
TheWhogg@reddit
You do pads at 6.5mm?? Good grief!
Turbulent_Winter549@reddit
Just look at the pads (pull the tire) and see how much meat is left on them. I would change out the rotors at the same time
J-Rag-@reddit
Just do pads and rotors when you gotta do brakes. Make sure you get a c clamp and push the brake piston back in and bleed the brakes when you're done.
As for 100k service. Just do what it needs. If it's due for oil change, change the oil. Same goes for transmission, coolant, etc. Dont need to do anything special
Tobazz@reddit
When you press the brakes and still end up in a wall
RepulsiveAnswer4202@reddit
On most of my small vehicles I just throw new rotors in when doing pads. Parts tend to be pretty cheap for the small guys.
I my truck I usually pad swap once per set of rotors as long as the thickness of the rotor is in spec. The rotors on my truck are pretty hefty so I usually burn a set of pads before the rotor hits it's min thickness.
If you are patient you can sometimes find a sale on rock auto brake kits. I think I picked up a set of Wagner rotors and pads for like 117 bucks for my 13 Kia Optima last year. My trucks rotors are usually around 100 a piece minimum.
Equana@reddit
Replace the brakes when the friction material on the pad is 2mm or less. Replace the rotors at the same time.
And do more research on your car.... it does not have a timing belt, it has a timing chain.
Cynyr36@reddit
Agreed about the thickness, however if they are at all close and i was already doing the hub I'd do the brakes too. I'm 98%of the labor on that side already.
buildyourown@reddit
Inspect thickness of brake pad material. Buy some fresh pads and compare. You are right, you will have them apart for the bearing so it's probably worth the extra steps. Also inspect rotors if there is grooving or a ridge they need to be turned/replaced.
Bulocoo@reddit
These days if you do brake pads just get the whole kit and do the rotors.
Then you are good for another 100k or so. If doing yourself pay close attention to the pucks when they come out. Some cars have an inner and outer puck only noted by a nipple on the backside.
Consider shopping around for a radiator flush at 100k. Don't pay a ton to a shop. It's a pretty easy job. You might get a better price at a radiator shop.
CeC-P@reddit
As soon as you get a wobbling vibration when braking that slows with the speed of the car, you need rotors. If you hear screeching and reduced braking capability, you likely need pads. And for the plugs, it's a Kia, so your engine is going to explode whether you change them or not because Kia's are awful.
Blu_yello_husky@reddit
Thats not true. What youre talking about is due to warped rotors, whuch has nothing to do with brake performance. Its what I like to call a "customer preference issue". Its only a problem if you dont like the vibration. It doesnt actually hurt anything if you leave it alone.
00Spiff@reddit (OP)
I'm trying to prolong the explosion as long as I can. Hopefully until I'm out of college.
SaurSig@reddit
That engine doesn't have a timing belt, it has a timing chain, which in general do not have a regular replacement interval.
As for the brakes, I'm at a point in my life where I don't usually mess around with putting new pads on used rotors anymore. I'd rather replace the rotors too and not have to worry about it for years.
The correct way to replace just the pads is to take the rotors to someone who resurfaces them, but not many places do that anymore and the cost might not be worth it.