New front brakes / now crazy vibrations

[RussB]

Did the car have any vibrations BEFORE the new pads & rotors?

Did the pistons push in smoothly when you compressed them, or was there resistance?

Do the front calipers slide smoothly on the pins? Did you clean and re-grease the pins?

[E Showell]

Do your new pads require bedding in? Did you follow manufacturer instructions for this process?

[theWIFES_S70]

Could he have knocked the ABS sensor or pinched its wires caused this to happen? If the rotor is new and the brake pads are new, what else could cause those vibrations? Could you post a video of the sound?

[volvofornia]

Hi Guys,

Thank you so much for the feedback so far.

Yesterday night I checked everything again. So far no loose bolts or missing parts. I reassembled everything and went back on an empty parking lot for a test drive. Same thing. This time I tried to listen where it comes from. Here are my observations so far.

The first mile while everything is cold I cant hear anything. I realized that ones the rotors get warm the right rotors starts grinding at the pads (I can hear that sound while I'm driving next to a wall and have the window open) Did this test with both sides and it only came up on the passanger side. After using the brake 20 times in a row (going down from 20 mph to 0) the brake starts to squeak very loud. At some point I had to close the window cause it was hurting my ears. Around the same time the squeak sound occurs the vibrations set in. As I mentioned before the vibrations start while the care is stopping down and only between 10-0 mph.

My conclusion is a defective part (rotor and/or pads). I used the Duralast brake pads (cheapest ones) and the ACDelco 18A706A Advantage rotors. The left side (drivers side) is perfectly fine only the right side causes this trouble.

I'll get another rotor (same type) in by tomorrow and start exchanging this one. If this doesnt help I start exchanging the pads as well.

Will also try to record the sound asap. Might be also a help for somebody else with the same kind of problem at some point. Its definitely really really scary.

Thanks so far!

[Cees Klumper]

My guess is that maybe the pad has too much free play in the caliper, and starts 'rocking' back and forth in turn hitting the disc and caliper so quickly that the movement causes the vibration and noise. I would try different pads (different brand) first, before changing the disc.

[volvofornia]

yeah might be the case. I think I'll return the brake pads tmw and exchange them against the next better ones from duralast. Amazon for some reason screwed the return process up and sends me now instead of new pads new rotors

[abscate]

The passenger side caliper could be hanging up. Is the rotor getting hot while you drive? Do not check with your finger..throw a cup of water on it.

[RussB]

The passenger side caliper could be hanging up. Is the rotor getting hot while you drive? Do not check with your finger..throw a cup of water on it.

I like to check with my finger, then throw the cup of cold water on the finger!

[RussB]

I still find it very unlikely it's a new pad or rotor issue. Then again, I'm a skeptic

[scot850]

I had a brand new set of Zimmerman rear rotors on our old 98 V70XC that were warped out the box. I had taken too long to fit them to return them, so had to have them turned. They were fine then. Also had a problem with 1 front one later shortly after fitting.

Our 06 XC70 had 3 sets of OE rotors fitted by the dealer and one turning in 10k miles, and since then they have been fine. Bad batch?

One of the most critical issues I find is that the hub faces are not cleaned off completely before new rotors are fitted. So when the rotors are bolted up they are not sitting flat causing vibration.

Many people think they can fit wheels ok, but I always suggest just nipping up the wheel bolts to snug in a star pattern and then torqueing to correct value.

Lastly, with winter on us, if you are using alloy wheels, they can easily get bent hitting a pot hole. Try moving the wheels on each side from front to back of the car and then drive again and see if the issue has moved from front to back. Do one side at a time and drive between to check.

This will help eliminate the wheels/tires being an issue.

Finally, check the calipers are free to move, and the slider pins are not bent/worn which allows the caliper to move and vibrate, also check that the pads move smoothly on their tracks and aren't binding.

Neil.