New brake pads and rotors now car brakes worse than before

I bought everything new and now my car can’t make emergency stop. I love how it feels smoother but I can be driving at 45 miles an hour and then quickly slam on the brakes all the way to the floor and it still won’t stop as quickly as I’d need it to. My previous brakes worked better although they didn’t feel this smooth. If the problem is the break fluid, why did it get worse all of a sudden?

Sounds l Iike a leak or a bad master cylinder. What exactly was replaced, and who diagnosed the problem and did the work? What year make, and model, and what’s the mileage?

I replaced just the rotors and brake pads. I did the work myself. It is a Hyundai elantra with 101,000 miles. My mechanic diagnosed it because of vibrations during hard braking.

Almost no information here, so there will be some basic questions.

Describe how you cleaned the new rotors. Not cleaning them thoroughly is about the only mistake you could have made.

I’m glad you tried at least one hard stop. How many did you do? You may have to do two more if one was all.

What brand of brake pads did you buy and how much did you pay for them? Are they semi-metallic, ceramic or organic.

No, I don’t know why the brakes don’t seem to work as well as before, except that the rotors are much smoother than the old ones although I doubt that that is a correct answer from me.

See how they work tomorrow.

“…then quickly slam on the brakes all the way to the floor…”

Hopefully, the OP is just using a euphemism for applying the brakes very hard.

If the brake pedal is actually going all the way to the floor, then there is a serious issue with the hydraulic system, and–if there is actually enough fluid in the system, and if the system has been correctly “bled”–then the next step would be replacing the master cylinder.

Is the brake pedal actually going all the way to the floor?
If so, PLEASE don’t drive this car until you have rectified the problem.

I suspect you did not follow the break-in procedure for new pads. I would pull the wheels and check for a bad surface on the rotor. Might need cleaning. Then follow the usual break-in procedure, hard stops from 20, 30, 40 mph, etc.


I hope you didn’t crack open a brake bleeder in order to retract the caliper pistons . . .

You are aware that new brakes have to be bedded in first, correct?

I am just an amateur who really loves the idea of fixing his own car. So I looked up a few videos on YouTube and felt confident enought to do it. everyone says how easy and fast it is to replace your own rotors and brake pads.
Pleasedodge I didn’t clean the new rotors. Didn’t know I had to. How do I clean them? I did about four hard stops. The brand is duralast and they are organic they costed 22 bucks.

Vdc yes then brake pedal does go all the way in when driving over 45 and I want to make a hard stop. under 45 I don’t need to hit the brakes so deep. And it is all the way in, not just to the point where there’s increased resistance so much that you can go any deeper.

hookie I never heard of a break in procedure, I will try that out right now. Thanks

db4690 I don’t think I cracked anything. I don’t know what a brake bleeder is. If it has to do with the brake caliper or bracket no I do not think I damaged it I didn’t I did not let that part hanging from the car. I’d hate to ask you to explain yourself but can you refer to an article or video explaining your comment please?

Is the ABS light blinking on when you brake?

Hi rod knox. No my model of car doesnt have abs

From your second post, it sounds like you indeed ARE able to press the brake pedal to the floor. That fact indicates you have something wrong in the hydraulic system, and could be as simple as air in the system, or as BustedKnuckles wrote, a bad component like the master cylinder. Others here will point you to finding the problem.

Meanwhile, as mentioned by @VDCdriver, do not drive the car in this condition.

well I read western…'s coment after i got back from testing again and trying to break in my brakes. And maybe this is another clue. i was hard braking out of town, and the first 2 or 3 times went great, i didnt even have to press the pedal all the way down to the floor. i even burned tires for about 3 feet. (remember, i dont have abs) but right after that the brakes went back to how they were yesterday. i found it weird that the first times i was able to lock the wheel to brake i was driving at around 30-40 mph. then the times after that i was driving well over 40 then it didnt burn or lock the tires after braking. does this help anyone?


Don’t do anything rash, but I have to inform you that, overall, I have had pretty bad experience with Duralast brakes (rotors AND pads)

Cracking open brake bleeder means loosening one of these

Cleaning brake rotors: Sometimes you get the obvious ones that have a coating of oil on them and you know what to do right away. Now, I don’t follow rules to the letter when it comes to buying a can of brake cleaner so I cleaned my last four rotors with carburetor cleaner. You have to clean the shiny surfaces that contact the pads and not worry about every last part of the rest of it.

My comments are obviously not all-knowing and come from brain cells that have been exposed to a lot of spray painting of car models in a non-ventilated basement. I try to pay attention to my brake jobs because I do have to stop the truck now and then. The brakes worked for years before I traded the truck.

As far as master cylinders go; they sometimes fail AS you’re replacing pads and rotors or during brake bleeding. That kind of thing seems like an impossibility but it happens more often than I care to think about. It’s not just the guy that does nine brake jobs a week who gets burned.

It looks like you bought parts as good as the rest of us get. Oops, just read the comment about Duralast brake parts and organic means asbestos. Also, I believe that the master cylinder may have quit on you.

Did you check the fluid in the reservoir to see if it is low? Have you ever changed the brake fluid? At 101,000 miles, it almost certainly needs new fluid.

I would say at 101,000 miles, the fluid has absorbed quite a bit of water and should be flushed.

From what the OP stated in the question, it seems this is a first time brake job and the necessity for - and intricacies of - bleeding brakes are not yet evident (didn’t pick up what “crack the bleeders” was about). That’s fine, sounds like he/she wants to learn. I was hoping someone else would give a clear and authoritative description on the process. There’s probably a link to a how-to video, but I’m not going to go hunting for it at the moment.

I’m guessing that there’s a simple problem of low brake fluid resulting in air in the system, accounting for the pedal going to the floor, though the OP is a bit vague about whether that’s really happening. Perhaps there is a problem with the master cylinder, but obviously the lines need to be bled first to eliminate the simplest problem.

I mainly didn’t want Luis to go out driving around until the fluid issue was addressed.

It’s hard to say from the OP’ers description whether there is a problem in the hydraulics or not. But unless you are super strong, you shouldn’t be able to press the brake pedal all the way to floor unless there is air in the brake lines. At least that isn’t possible on either of my cars. Installing new pads rarely results in air in the brake lines unless the caliper or some other bleed screw is loosened. But maybe that isn’t what the OP’er actually means. Rather he’s saying when he presses the brake pedal at full force he’s not getting the expected stopping power.

If it is the latter, I’d suspect the problem is the new discs were not properly cleaned before the install. The manufacturer of the discs coats them with a substance so they won’t rust while sitting on the part’s store shelf. But if this coating isn’t entirely removed, at the first press of the brakes, the coating will clog the pads and poor braking performance would be the result.

It might be possible to simply re-remove the pads, clean them off with a wire brush, clean the rotors with an appropriate solvent, maybe take some 160 grit AlO2 sandpaper and roughen the surface of both the pads and the disc, and return to normal braking performance.

The OP would be wise to at least consult a local shop for guidance on this, as safety for himself and others is involved.


cracking brake bleeder = opening (cracking) the brake bleeder screw

Some guys do this to retract the caliper pistons more easily

I DO NOT do this because I don’t want to introduce air into the lines during a simple pad slap

Yes, I know, thanks for following up on that. As you noticed earlier, it seemed the OP misunderstood “cracking the bleeders” as damage, which it is not.

I was pointing out that the OP was not aware of the bleeders and their purpose, and that you had wisely clarified that in your previous post. I added my comment to illustrate the OP’s beginner level of understanding of the system, and his/her need for more detailed instructions, as well as a potential explanation of the problem which arose after the pad replacement. I suspect the problem will be solved by a proper bleeding of all the lines, purging the system of old brake fluid in the process. Yes, there may be a MC problem, but not necessarily.