New front brakes / now crazy vibrations

volvofornia · Post by **volvofornia** » 25 Jan 2016, 13:38

Hi,

Changed my rotors and pads yesterday and now I get this crazy vibrations when the car comes to a stop.

The vibrations are so strong that it shakes the whole car and I can feel them all over my body. The frequency feels very high. Do t know if that because everything has to brake in or I did a mistake.

Any thoughts?

harryhendo · Post by **harryhendo** » 25 Jan 2016, 13:45

Did you clean the rotors with brake cleaner or some grease cutting solution? It is very important to take off the coating used to keep the rotor from rusting during storage or shipping.

Also, did you tighten the wheel nuts to the correct torque? This is important to get a true break in of the rotors.

Post by **kahl** » 25 Jan 2016, 13:50

I would not drive the car. Something was not tightened. Take you pick:bracket, caliper or wheel lugs. You need to get the front end up on jack stands and find out what was not tightened or what came loose. Check you suspension also, with the violent vibration no you are experiencing the issue should be easy to find.

volvofornia · Post by **volvofornia** » 25 Jan 2016, 17:39

Just started driving after the car was standing for a couple of hours and the vibrations stopped. I guess it has something to do with the temperature and the brakes head up. What could that possible be what only occurs while the rotors/pads are hot?!

volvofornia · Post by **volvofornia** » 25 Jan 2016, 17:44

Btw: I tried to listen to them during driving. I mean I can hear the pads slightly grinding against the rotor. Maybe this has to do with it?

volvofornia · Post by **volvofornia** » 25 Jan 2016, 17:47

harryhendo wrote:Did you clean the rotors with brake cleaner or some grease cutting solution? It is very important to take off the coating used to keep the rotor from rusting during storage or shipping.

Also, did you tighten the wheel nuts to the correct torque? This is important to get a true break in of the rotors.

I did clean the rotors with a break cleaner several times. I didn't use a torque wrench for the wheels but never had a problem so far doing it without one (I know it's best to use a proper torque wrench)

volvofornia · Post by **volvofornia** » 25 Jan 2016, 20:32

Ok, opened everything up and I could see that on the left side the dust boot came of the caliber. One side is still attached to the piston but the other side is completely out of the housing.

Tried to put it back into but for some reason it will not work. Any tips how to replace this dust cap? Thanks!

harryhendo · Post by **harryhendo** » 26 Jan 2016, 06:47

It is good practice to clean the caliper piston before you use a C-clamp to recess it back into its seat. It looks like what happened in your case is that when the piston was pressed back into its seat, the rubber boot caught on the dirt on the piston, and, when you pushed on the brakes, and the piston moved inward out of its seat, the boot came along with the piston and detached from the caliper.

I would remove the rubber boot entirely,clean the boot with silicone spray, clean the piston well, and then recess the piston back into the caliper using your C clamp. Then very gently move a blunt wide screwdriver around the back edge of the boot to press it back into the caliper.

That being said, I doubt if this extracted boot had anything to do with the vibration you felt.

Make sure to use copper/hi temp grease on the upper and lower pins so that they slide easily. Also make sure the pins are fully compressing to the caliper... they have a rectangular tab that needs to be rotated properly to fit into the caliper securely.

Post by **benpineapple** » 26 Jan 2016, 06:52

I'd recommend replacing the boot, if it seems like the boot itself is torn or in rough shape.

https://www.fcpeuro.com/products/volvo- ... 850-271583

Never heard of brakes vibrating like the way you describe immediately after an install. Likely something very loose.

Post by **cn90** » 26 Jan 2016, 09:11

You need new boot, possible new seal.
See the DIY below...

https://www.matthewsvolvosite.com/forums ... hp?t=37721