Question on the Brakes

Richardd

Member
I'm new to this site and in the market of buying a CX9. I test drive one and it rode great and felt good too. The only problem I notice was, when I step on the brakes, going about 40 mpg, it was vibrating, (Warp rotors), was the first thing can in mind. I asked the salesman and he had no real answer for me. But he did give a B/S. that it's the new braking systems. I know what ABS braking system fells like and it was not. I just asking, if anyone had or having problem with the brakes.
 
CX-9 brakes vibrate like a homely ladies dildo. I am not sure, but I think it has something to do with cheap factory rotors. I live in DC where traffic goes from 80 mph to 5 mph in .5 seconds, so it plays hell on the rotors. I expect when I take my car in to have a brake job done they will have to replace the factory rotors with better aftermarket ones.
 
I guess every car in DC have been in an accident, since even a 911 Turbo can do no better than ~4s from 60-0. Let alone 80-5 in 0.5 secs :p
 
I never heard of warped rotors from the factory. I wonder if your test mule had after market rims which then means the clowns used an impact wrench on them and over torqued the lug nuts warping the rotors.

As far as cheap rotors, unless a vehicle is performance oriented (still a 50/50 shot) then the rotors are usually good and will not warp due to long or even heavy duty use. As far as standard equipment rotors on non performance based vehicles, they all suck and will eventually warp. When, the better ones make it 25-30k and the crappier ones you notice at 10-15k
 
Rotors can also warp if they were very hot and cold water splashes on them. Maybe this CX-9 was driven and then taken to a car wash.
 
AFAIK,
There are two common causes for the so called "warped rotors".
- over-tightened (>150ft-lb, spec is within 80-100ft-lb) nuts causing the rotors to warp
- brake dust/rust accumulated on the rotors causing uneven surface, therefore causing pads to vibrate when applied on the rotors.

For the 1st, you need to check the torque on the nuts. For the 2nd, a simple resurfacing will fix it. Since the vehicle is new, and probably has sit there in the lot for a while, I am guessing 2nd cause unless dealer had, for some reason, over-tighten the nuts.

Finally, I have no vibration issue with the brakes on my CX9. I have experienced a few emergent brakings. My prior car was BMW 540iA. The brake on CX9 is about 90% as good (w/o the infamous brake dust of BMW), which is not bad for the price of CX9.

The warranty on brakes is 1yr/12K whichever comes first.
 
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