Rotors Moving/Clunking
Rotors Moving/Clunking OK so I know that the rotors are moving. I can see it when I spin the front wheel in one direction and someone in the car hits the brakes. The rotor turns and clunks against the wheel studs. The size of the stud and the size of the holes in the rotors are different enough that there is some play in them. I am using Powerstop rotors and had a pair of rotors that did the same thing before these. It is not a good sound and only does it when I change the travel direction from forward to reverse and reverse to forward. The rotors only move once but I still don’t like the fact that it happens at all. The car has 36,000 miles on it.
Has anyone had this same issue? How did you fix it?
Has anyone had this same issue? How did you fix it?
TECH Apprentice
Joined: Dec 2006
Posts: 343
Likes: 1
From: Petaluma, Ca
My car does this too. I was thinking it was the retainer clips on the calipers not holding the brake pads still. I have aftermarket pads on the car now. My stock pads don't make the noise, but I don't like the way they feel (clamping force) when I step on the pedal, so I run the aftermarket pads and just live with it. However, they didn't make noise when they were new. But I don't remember when and at what point of wear they started moving in the calipers. At least, thats what I think is going on...
Well I know for a fact that the rotor is moving. I took the wheel off, torqued the lugs to 100ft-lbs, spun the hub and had someone hit the brakes. You can see the rotor turning. There must be a 1/16" or so of play in the rotor holes for the wheel studs and the rotor just moves.
What should I do here, anyone?
What should I do here, anyone?
Does anyone think this will cause the studs any undue stress? I'll have a machine shop make me something that will fill the gap in the rotor holes if it will reduce any safety issues. Slowing that car down is pretty important seeing as I drive it like I stole it.
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unless your studs are worn, or the stud holes in your rotors are elongated from them previously not being torqued right, or the lugs are not torqued correct, i do not know how they would otherwise be moving back and forth........hmm
And yes, I've wondered about that a few times myself......
TECH Apprentice
Joined: Dec 2006
Posts: 343
Likes: 1
From: Petaluma, Ca
The holes in the rotors, for the studs, as several folks have already noticed, are a bit oversized. Mine are also. You torque the wheels studs to 100 ft/lbs, but look at it this way....the brakes have to generate a LOT more than 100 ft lbs of torque, to stop a 3500 pound car. Therefore, the rotors are going to "move around" a little.
And yes, I've wondered about that a few times myself......
And yes, I've wondered about that a few times myself......
The rotor hat is crushed between the wheel and the wheel hub. It is the lug nuts and wheel studs that clamp everything together.
The wheel, brake rotor hat and hub become one solid assembly when correctly put together.
If you're tightening the lug nuts properly (as it appears you are) you need to look elsewhere as to why the rotor hat isn't being clamped properly.
What lug nuts are you using?
The wheel, brake rotor hat and hub become one solid assembly when correctly put together.
If you're tightening the lug nuts properly (as it appears you are) you need to look elsewhere as to why the rotor hat isn't being clamped properly.
What lug nuts are you using?
With the exception of brand everything is stock. Original stock lug nuts, original stock wheel studs, original stock wheels. The clips are stock and lock the pads in place. I really don't think they are a problem at all since I can't see or hear them moving when I "test" it all out.
I think leadfoot4 and others are right. I'm not doing anything wrong. I am just hearing it louder than others do. Which is surprising because the car has no mufflers and is undoubtedly the loudest car in town in the exhaust department.
I guess I am just being too **** but this is my only "toy" car afterall.
I think leadfoot4 and others are right. I'm not doing anything wrong. I am just hearing it louder than others do. Which is surprising because the car has no mufflers and is undoubtedly the loudest car in town in the exhaust department.
I guess I am just being too **** but this is my only "toy" car afterall.
Teching In
Joined: Jun 2014
Posts: 1
Likes: 0
Hi I was wondering if anyone ever figured out why this was happening. I am having the same problem with the rotor moving when going from reverse to drive and visa versa. And for those of you saying that it can't be the rotor it is. I marked the rotor and my rim put it in drive and moved a lil bit and hit the brake, heard the clunk and then checked my marks and they were not lined up. I've called the technical support and they basically said that it's impossible and that there was something in the way. I've checked 3 times myself and even had a mechanic look at it and it's still happening, even when I over torque the lug nuts. I can't figure it out so if anyone has an answer please let me know. The only thing I can think of is to return the rotors and get a different set. Thanks.
Welcome to LS1tech!
It looks like you've actually searched and found info about your exact problem-bravo!
Can you take a picture of the mark on the rotor before & after it moves?
You'll need to put the pictures on a website like photobucket then add the links to them using the yellow photo box above here.
It looks like you've actually searched and found info about your exact problem-bravo!
Can you take a picture of the mark on the rotor before & after it moves?
You'll need to put the pictures on a website like photobucket then add the links to them using the yellow photo box above here.
Registered User
Joined: Aug 2020
Posts: 2
Likes: 0
Brake Rotors Clunking I have this problem and I know what it is!!! ..I replaced my Rotors with some aftermarket ones and when I did this is when it started.
They don't fit perfectly and as a result you have all those close tolerance areas were they should be touching but don't .
Now if you have the factory ones and they are doing it...I would suggest you pull them off and clean and lube (WD-40) the areas on the hub and rim.
This was a problem in the old days with drum brakes and they sold these little thin metal "Keepers" that you could slide down on the threads of the wheel stud and would keep pressure on the drum...I'm going to see if I can find some and try them on my Rotors.
That's it guys!!!...Good luck
They don't fit perfectly and as a result you have all those close tolerance areas were they should be touching but don't .
Now if you have the factory ones and they are doing it...I would suggest you pull them off and clean and lube (WD-40) the areas on the hub and rim.
This was a problem in the old days with drum brakes and they sold these little thin metal "Keepers" that you could slide down on the threads of the wheel stud and would keep pressure on the drum...I'm going to see if I can find some and try them on my Rotors.
That's it guys!!!...Good luck
Registered User
Joined: Aug 2020
Posts: 2
Likes: 0
Registered User
Joined: Sep 2021
Posts: 1
Likes: 0
You misunderstand torque vs clamping force The holes in the rotors, for the studs, as several folks have already noticed, are a bit oversized. Mine are also. You torque the wheels studs to 100 ft/lbs, but look at it this way....the brakes have to generate a LOT more than 100 ft lbs of torque, to stop a 3500 pound car. Therefore, the rotors are going to "move around" a little.
And yes, I've wondered about that a few times myself......
And yes, I've wondered about that a few times myself......
Clamping force can be determined from the fastener properties and base material properties, but it's significantly higher than the fastener torque.
One equation to use is T = KDP, where T = tightening torque, lb-in.; K = torque-friction coefficient; D = nominal bolt diameter, in.; and P = bolt clamping load developed by tightening.
So, P=T/KD. If the coefficient of friction is .5 and the diameter is .468, the clamping force at 100ft-lb of torque is 427 lbs.
I have a similar issue on a vehicle.
the lug studs are 12mm (.468) and the rotor lug holes are .55 (14mm).
Whenever I change direction or even release the brakes or engage them, I hear a pop. And it's scary as hell sometimes.