Braking noise and slipping

toyota
sienna

#1

I swear, I have a lemon. I keep coming up with unusual issues with my can. Ok, so I just had to replace brakes and rotors on the front. Now when I break, it makes a mechanical whine/squeal and slips for a second. (Randomly, not evertime) The noise seems to come from peddle.
It’s not a grinding noise like you would hear with low pads or rotor, or even caliper seizing up. I’m hoping nothing serious. Possibly bad abs pump??


#2

OK, noise while braking, you think its coming from the pedal. Is the noise a squeal or a whine? Does the ABS light come on?


#3

In addition to the questions that Mustangman posed regarding the brakes and the brake pedal, I am wondering…what does the OP mean by “slips for a second”.

What exactly does that mean?


#4

Sounds like intermittent ABS activation caused by a failing ABS wheel sensor or connection.


#5

Mustangman, it’s more of a loud mechanical whine and No the ABS light does not come on at all.

VDCDriver, I mean that when the brakes are engaged, they seem to slip. Sort of like when the ABS engages. But it’s only a split second.

Insightful, if it where any ABS sensor or connection, wouldn’t the ABS light come on?


#6

There is no way to sugar coat this. You are asking questions that lead me to believe you can’t fix this brake problem yourself. If that is correct why are you not having a brake shop solve this instead of wasting time on the internet. Brakes that don’t work properly are dangerous for you and everyone around you.


#7

No ABS light means the ABS pump is not running nor are the valves cycling. More basic problem is likely.

The “slips” part leads me to doubt the brakes are applying correctly. Does it pull to one side or the other?

If it were my car, I’d pull the wheels and inspect and then remove the brake pads, check the caliper slides, reassemble and have a buddy apply the brakes I can get a good look and feel for the parts.


#8

I’m asking this because I just got them fixed at a shop and they say they can’t replicate the sound and say everything looks fine. So hile we wait for second opinion, I thought I’d ask. Thank you for your suggestion.


#9

Strangely it doesn’t pull.


#10

Well it shouldn’t pull…

Its been inspected, as you posted, and they couldn’t replicate the noise. If it is a problem, it will only get worse. If its just a “break-in” anomaly, it will go away. Wait and see.


#11

If you want the same shop to troubleshoot the issue, they need to witness it. Unfortunately, this means that you have to wait until it gets more frequent. If they still say they can’t hear the squeal and feel the slip, take them out for a ride and see if the problem shows up when you are both in the car.


#12

I’m gonna echo @VOLVO_V70 here and ask you to clarify even further what you mean when you say it “slips.”

What exactly is happening? I know you say it’s like when ABS activates, but what do you mean by that? The pedal vibrates? You hear a buzzing noise? The pedal gets hard?

If it’s not pulling when this happens that leads me to suspect that it’s not a problem confined to one wheel, and it’s fairly unlikely for even a careless shop to break brakes on both sides of the vehicle in exactly the same way so as to reduce braking performance equally on each side.

So that makes me suspect something else is going on, and we really need a very detailed, thorough description of everything that happens when the problem manifests to have an idea of where to even begin thinking about this.


#13

Actually, I was the one who asked for the clarification about “slipping”.
Unfortunately, the OP’s…explanation…did not help.

I don’t know about anyone else, but all of my cars with ABS have rapidly pulsed their brakes, and their brake pedals have vibrated a bit, when the ABS was activated, but none of them ever exhibited “slipping” of the brakes when the ABS activated.

Because the…explanation…made little or no sense to me, I terminated my responses at that point.


#14

When you engage the brakes, but then it feels like the brakes slip, then re- engage. Not pulsae. I don’t know how to clarify that any better for you. But if you can’t answer that’s ok.


#15

Brakes engage, then slip briefly, then re-engage. I’ve had that happen when brake fluid leaks and gets onto the drums of my truck. Same thing could happen if brake it got onto the rotors on disc brakes. That’d be my first guess anyway. The comments above to have someone experience remove the wheels and take a look at what is going on of course is the first thing to do. Guessing isn’t a good strategy with brakes. Fortunately disc brakes are pretty easy to inspect for the most part.

For the squeaking/squealing, that could be due to brake fluid on the rotors too, but my first guess is the shop didn’t install Toyota OEM pads with all the required anti-squeal do-dads that go with them. Suggest to ask about that.


#16

So found this video on YouTube https://youtu.be/sMmzdITv1y8
This is the exact noise. So, thank you mustangman, for leading me on this direction. (Weird though my ABS light is still out) My only question now would be, can I safely drive the car. The ABS system only prevents brakes locking up correct.

I’ll admit I don’t know alot about cats, obvious huh. But I just came for advice and know how from people who do. Thanks to all who helped out.


#17

All I can hear is engine noise in that video. But my ears aren’t so good any more.

This site is supposed to be good for cats:


(sorry, couldn’t resist)


#18

I agree.
All that I can hear in that video is engine noise.


#19

Update,
Just got back from shop. They ran a diagnostic and No codes came up, strange. But he said that there is no doubt it’s something with the ABS system, we just have to pinpoint the problem. So the ABS is temporarily disengaged. The noise has stopped! Now to find where.

Thanks again


#20

Very sorry. I got the V guys confused. :frowning:

If @GeorgeSanJose 's theory is correct, ABS would engage if one rotor had brake fluid slowly dripping onto it and the other did not. The system only detects unexpected braking conditions - it’s not smart enough to know that one side’s wheel is spinning faster than the other side’s because of contamination on the rotor versus slipping on ice. So, before you let them tear into the ABS system and charge you a lot of money, make sure there isn’t a slow drip of brake fluid onto one of the rotors.