Brake problem on 2004 Mercury Mountaineer?

Question

I have taken my suv to the dealer 9 times, they either say the problem is fixed or they cannot duplicate the problem...not everytime but occasionally when you apply the brakes, they will "pop" and you can feel the whole car jerk??? Any idea whats causing this???Its not the pads, they are new

Answer 1

It sounds like something is sticking. The brakes will need to be disasembled and inspected closely. That is something that the dealer may not want to spend time doing. Take it to them again and ask about speaking to a factory representative. This may be enough to make them want to spend a little more time on your problem>

Answer 2

It sounds as if your master cylinder is suspect or one of the brake hoses or lines has an obstruction. Have your brake system flushed with a complete fluid change. The mechanic can easily see if there's an interrupted flow of fluid at each individual bleeder screw as this is being done.

I would put the truck on four jackstands with the wheels off and start the motor. Put it in 4 wheel drive and let all the hubs turn. Have someone inrermittently push the brake petal while turning the steering wheel right and left. Look closely at each brake caliper and see if you can hear, feel or see a jerk snap or pop. If it has drums in the rear take plenty of time watching and listening to them also.
You may have a disc brake slider pin and bushing problem. Pull the calipers and inspect the pins and bushings if you see the slightest amount of scoring or rust on any of the pins and replace along with new slider bushings, Re-grease with synthetic brake grease, avalable at NAPA or Car Quest. Make sure your caliper pistons are all free by squeezing them back inside the caliper.

I'm somewhat puzzled by all this as your vehicle is so new.