Break pads - how do find if they need replacement

[E53inLA]

I have very little trust in the brake pad wear sensor system. When our X5 was still young, and within the initial 4 year maintenance period, the passenger front side started making terrible noise one day, and when we took it to the BMW dealer, they said the pad was completely shot.

I realize the front pad sensor is on the driver side, but the fact that the passenger side was making that much noise and the driver side sensor hadn't fired a warning light, left me with the impression that particular sub-system was a poor design, and could not be relied upon.

[JCL]

The sensors work fine in my experience, as long as the four pads on either axle wear at the same rate. If they don't, you may get metal on metal before the warning light.

On our X3, I noticed that one right rear pad is wearing faster than the other, it is thin, and the brake pad light isn't on yet. I will change the pads soon and not wait for the light. I was in there to change the rear springs out, and saw it; the vehicle is 7 years old on original brakes with over 100,000 km so not surprising that they are worn, and it is likely that cleaning up the caliper slides and applying high temperature grease to the pad ears will correct the wear imbalance.

To the OP: if you trust your mechanic, then yes, it is likely that you need brake pads even though the light isn't on yet. Don't turn the rotors on a lathe, they aren't very thick. If they have worn thin or the surface finish isn't good, it is better to just replace them.

[E53inLA]

Originally Posted by JCL

the vehicle is 7 years old on original brakes with over 100,000 km so not surprising that they are worn, and it is likely that cleaning up the caliper slides and applying high temperature grease to the pad ears will correct the wear imbalance.

I'm jealous! My cousin who lives in CT drives a 5 series and tells me he is still on original pads. He added that he does a lot of highway miles. OTOH, we live in the hills, and a couple of the roads have speed bumps. I don't think we ever got even 10,000 miles from a set of front pads. Everyone has told me the hills and the weight of the X5 will wear the pads fast, but why the sensor doesn't fire on the drivers side before the passenger side is still a bit of a mystery to me. It has consistently been that way with each set of front pads. We are the original owner of the 2005 X5.

[JCL]

Original front pads on the X3 still have 30-40% left at 102,000 km.

Mix of city and highway, manual transmission.

On the X5, I was closer to 40,000 km for front pads. Heavier vehicle.

[upallnight]

Originally Posted by E53inLA

I have very little trust in the brake pad wear sensor system. When our X5 was still young, and within the initial 4 year maintenance period, the passenger front side started making terrible noise one day, and when we took it to the BMW dealer, they said the pad was completely shot.

I realize the front pad sensor is on the driver side, but the fact that the passenger side was making that much noise and the driver side sensor hadn't fired a warning light, left me with the impression that particular sub-system was a poor design, and could not be relied upon.

[bcredliner]

If the pads on one end of an X5 are not wearing at very nearly the same rates something is amiss. That should be caught and corrected in BMW recommended visual checks in the maintenance schedule. Sensors on all for wheels would be overkill.

[ants_oz]

If a vehicle gets to the point where one or more pads has worn through to the backing, and the owner is not aware the pads were needing replacement, then the owner has not been undertaking necessary maintenance and inspections. The buck stops right there.

[Elvis 3.0]

also, your tech may have had the foresight to just replace them now. that is, he may be very well aware of the sensor and its capacity. Seeing that it was close to the breaking point he may have suggested to just go ahead and do it. If I had the wheel off and it was close enough I may replace the pads now before the sensor goes ( and therefore saving the sensor for the next set of newly replaced pads)

[Kisu_san]

Originally Posted by Doru

Answers below:

Dear Doru, Thanks for the picture. It is CV boot 5 in picture. It has some grease around. I remember my mechanic changed it 1 year ago in front and charged me some 1.5 hours of labor. Is it very common for CV boots to get worn that fast. Even though CV boot cost is less, labors costs seems to be high.

[Kisu_san]

I have decided to change the pads. Any recommendations. I got a quote for TEXTAR, HAWK, ATE (Ceramic). Any experience with these brands ?

And also would it is good to change break fluid at the same time. I got a clock symbol