My brakes have developed a high-pitched squeal in the past 3 weeks. It happens when I apply medium to heavy brake pressure. The thing is, it seems to come and go... I've tried shooting the front brakes with brake cleaner, which seemed to alleviate the problem for a week but now the squeal is back.

At 33,000 miles, the front brakes were 25%-35% worn. Am I hearing the wear indicators? (do the factory pads even have wear indicators?)

The specs:
2000 4Runner
45,000 miles
32" tires
Towed a 3,500 lb. trailer about 5 times

 

Here is a link on pads.

http://www.nationalfleetparts.com/3types.htm

 

To tell you the truth, when my stock pads were gone, I never knew. No noise or anything. The only thing I noticed was that the brakes caused a very slight groaning noise right before the tires stopped rolling.

Some ideas:

1.) The pads have crystallized from constant overheating (caused by rears being out of adjustment). You can save the pads and avoid a big brake job by sanding them down.

2.) If you've had the brakes replaced with non-factory parts (sorry if I missed something in the first post), then they might have used semi-metallic pads which are of lower quality and noisier than ceramic pads.

3.) Your pads are getting constantly dirty from off-roading (this is usually my case ) causing the noise.

Let me know what you think it might be and I'll provide more info.

 

I would lean toward the wear indicators. It is possible that something scored the rotor too.

I would replace the pads and have the rotors turned.

My .03