Noise vibration from slotted/drilled rotors?

[WobblyElvis]

I bought a 99 Caravan with slotted/drilled rotors. Don't ask me why anyone would do that. Drove for about a year without any noticeable noise but it has slowly started to make a noise/vibration, similar to the rumble strips at the side of the highway, while applying the brakes. The brakes look fine and they are not producing an excessive amount of brake dust and this doesn't feel like warped rotors. It's getting worse fast. I can only guess it's because the chamfer on the edge of the pads has worn away.

Anyone here experienced this? For all I know it's not the rotors.

 

[Chris Meutsch]

For what it's worth, I do have the Stoptech slotted/drilled rotors and their pads on the front of my supercar (*cough cough, 2005 Honda CR-V with 242k*) and they do this exact sound you mention. No real vibration however. I live with it, it was a good deal on Rockauto.

 

[meep]

I have 2 sets of "slotted" raybestos Advanced Tech rotors. One set is whisper quiet. The other does do this under hard braking.

 

[ARCOgraphite]

Some have suggested brake "judder" can be caused by uneven deposition of material onto rotor surface causing uneven "grab".

when doing a pad -only renew, I used to hit the surface of the old rotors with a grinder wheel with the rotor on the car to deglaze and give a new surface to bed. I also chamfered the outer circumference. ( I also filed the leading edge of the pads and cross cut "out-gas" slots into the pads with a hacksaw.'

Maybe that, or hit rotors with a hard wire brush to deglaze - on the car wheel off and rotate the rotor either with engine or by hand.

Some dealers have caliper mount brake lathes - but now your talking some real money.

 

[Rolla07]

Id say rotors are no longer in spec. Problem with drilled and slotted is I think they are more prone to warping, it may not be evident they are warped but even being slightly so might cause that. Id change out the rotors and install new pads, fresh lube on the slides and you should be good.

 

[sprite1741]

Sounds like warped rotors in the front. If someone turned them once, get rid of them. Brakes and rotors are cheap now. I have cross drilled rotors with ceramic pads from O'Reilly, $150 total for both fronts with $20 coupon. Easy 1.5 hour job in the driveway. Don't put up with bad brakes it's not worth it. Mine are 2 years old now and still fine.

 

[WobblyElvis]

This is not warped rotors, unless it's some kind of warp I have never seen before. Much higher frequency and it doesn't pull or oscillate the steering wheel. I'm surprised how loud it is when braking hard. If it wasn't raining today, I'd pull it apart this afternoon. If I don't find an obvious problem I'll just change the rotors and see if that works.

 

[sprite1741]

Take it apart and see. I would put new stuff on since you have it apart anyway. I have had bad rotors sound like a rumble strips at high speed. I hate that. New rotors and pads cures it. Could be something loose, but you have to start removing things anyway. just use the auto part store parts. They are all from China now and inexpensive. I never put up with brake problems, too easy to fix.

 

[RooflessVW]

Originally Posted By: WobblyElvis
I can only guess it's because the chamfer on the edge of the pads has worn away.

Bingo.

 

[ARCOgraphite]

Try refinishing the rotor surface on the vehicle FIRST before you go nutty.

Do you have a dial gauge? ( surface profilometer)

with the wheels torqued on, check back side of rotor about 3/16 from edge.

anything more than 3mils TRO is too much. Sometime wheels get loose and stuff moves around behind the rotor hat and axle flange. - Unless these are 1 piece with roller race receivers.

 

[A_Harman]

I've tried drilled and slotted rotors from time to time, but have never liked them. I don't like the noise they make, the higher wear rate of the pads, and the non-linear feel they give the braking system. I always go back to smooth rotors.

 

[JasonC]

About 10 years ago I put a set of drilled and slotted rotors on an 05 Explorer. It sounded like a baseball card in a bicycle spoke whenever I applied the brakes. Couldn't stand the noise so I threw them in the trash and have never used another drilled and slotted rotor again.

 

[4WD]

Put my first thousand miles on new Callahan drilled/slotted rotors with Power Stop Truck & Tow pads. Smooth, quiet, and noticeably better stopping power over stock rotors with Bosch pads. Also like they are more dust and rust free. (Rotor is zinc or ? coated) Time will tell - but needed to improve brakes on GMC Canyon ...

 

[07titan]

Been nearly a year, installed front brakes, powerstop drilled/slotted rotors and pads(kit koe211), rear brakes,powerstop rotors smooth and pads (kit koe2445), on my 07 titan, no problems with any noise or wobble and have very good stopping power,,,believe me, had 2 situations, which good have gone bad but didn't, good brakes. So far,, happy with what I have, purchased from rock auto.

 

[WobblyElvis]

I finally got around to taking the brakes apart and the problem was obvious. The outside surface of the rotors looked fine but the backside, not so much. Can't help but think this failure was related to the fact they rotors were drill/slotted. The outer pads [not driven by the piston] were wearing much faster than the inner pads. Don't make no sense to me. Put on new rotors. Problem solved! I hope.

 

[HangFire]

It looks like they were rusting from the inside out, thus expanded hole sizes.

Uneven rotor side wear could be stuck pins/tracks/slides, seized calipers, or asymmetric pad hardness like Adaptive One pads.

 

[RooflessVW]

You need to lube your slide pins.

 

[WobblyElvis]

The calipers and slide pins appear to function perfectly fine. What is odd is the outer pads are wearing much faster than the inner pads. Normally if the caliper will not move, the inner pads wear first but this is not the case here. The inside surface of the rotors fell apart. Looks like rust as Hangfire mentioned.