Intermittent Vibration

[$100T2]

I have a 2009 CX9 Grand Touring with 105k miles. I just had both front wheel bearings changed about 6 weeks ago, everything was smooth sailing until last week.

Now, I have an intermittent grinding/vibration. Start it up in the morning, drive it for 10-15 minutes and it starts to grind... Then it vibrates and actually shakes the steering wheel, almost like it would with a bad tie-rod end or a seriously out of balance tire. I can see it in the steering wheel and feel it in the gas and brake pedals. Hit the brakes and it shakes like mad. Then, five minutes later, it all goes away, everything is smooth. Sometimes it comes back 20 minutes later, or 5 minutes later, or not at all until it's been sitting for a while.

I have NO clue what this could be. From reading other threads on the forum, I'm thinking either the pilot bearing on the rear driveshaft, or the new bearings weren't installed right/torqued down right.

Any ideas?

 

[eskimo0101]

Always start with what changed recently, and that's the wheel bearing. That shake is either brakes or play somewhere and the fact that it comes and goes tells me it's definitely not brakes.

Someone familiar with troubleshooting front end issues needs to get the vehicle up in the air and start looking for the play.

 

[$100T2]

Took it back to my mechanic, he kept it for a week and couldn't duplicate the issue, so he changed the wheel bearings again (at no charge!)... Then he drove it last night and it did it...

Turns out it's the passenger front caliper over heating and seizing... The dealership I bought it from told me they put new calipers on it, my mechanic said there's NO way they were new or changed... The dealership also told me they used Mazda rotors and pads, but we know that was BS too.

So he's going to change both front calipers, brake fluid, and hoses if needed. Hopefully then it will be all sorted.

 

[eskimo0101]

Good luck. It doesn't make sense that intermittent shaking is coming from a caliper issue.

Did you notice a lot of pad buildup on one rim? Hot brake smell after driving? Lots of heat coming from one wheel? These are all signs of a sticking caliper. Vibration caused by brakes is almost always uneven pad buildup on rotors (often incorrectly labeled "warped rotors"). That kind of vibration would be there every time you brake though.

Intermittent vibrations come from play somewhere. The vibrations will come and go because under some circumstances the right pressures are applied so that the part with play is pushed to the end of it's range. The vibrations come back when the part isn't under pressure and the play oscillates from one side to the other. EX: a bad wheel bearing while making a turn will take up all the slop in the bear and it won't vibrate. Get going down the road at a steady pace though and the pressure may become static enough that a resonant vibration will start where the wheel bounces between the two extremes of the bearing's play and you feel the vibration in the wheel. The same thing can happen with ball joints, tie rods etc.

 

[$100T2]

The caliper on the right side was over-heating. Got it back Saturday, drove over 300 miles with it between the weekend and my commute to work this morning and it's perfect.