Inboard disc pad wears out much faster

[Thump553]

I just replaced the front disc brake pads and rotors on my '96 Saab 900. I had to replace the rotors because one of the pads went too far and gouged the rotor badly. On each side the innermost pad (the one that moves) was far more worn than the outer one. Is that normal or is it a sign of something wrong?

Unfortunately these pads don't have wear detections and it is nearly impossible to get a decent visual inspection of the inside pads without pulling off the caliper.

 

[MiataNC]

The caliper should slide to allow both pads to wear evenly. If only one pad is wearing, then the odds are the sliders are gummed up or frozen.

 

[jagec]

Yup, sticky caliper.

 

[boomerang]

In my experience, it's not at all uncommon. I believe this problem is "engineered" into the system and I don't know the fix.

About all you can do is make certain that the caliper is able to slide freely inboard and outboard by whatever means are provided. (There are numerous ways this is done, I don't know how Saab does it.) Also, I have filed the abutment surfaces on the backing plates to make sure it slides freely in the caliper. There is always the possibility that the pad hangs and will not retract the minute amount necessary to keep it from wearing against the rotor.

The downside to filing like this is that if you get carried away, you can actually get noise when the brakes are applied. The pad will clunk against the caliper.

I hope this is understandable.

 

[Pacfanweb]

I agree, this is normal on lots of cars. Just make sure your calipers slide freely, as mentioned before.

 

[Zenmervolt]

As others have said, on floating caliper designs it's common for the pad on the piston side to wear a bit more than the other pad. Even though the caliper does slide, all of the force is provided by the pad on the piston side, so that pad naturally has a little more pressure on it.

Still, the difference in wear should not be excessive.

ZV