Hi everyone. Please read the entire posting before posting a reply. I wanted to describe in full detail what the problem is because this is not a usual brake issue, especially since I just had most of the brake components replaced last year (pads, rotors, calipers, master cylinder, most lines (most metal lines, all rubber hoses). Here it goes. About a month ago, I was driving in the Catskill Mountains. I noticed that when I am driving down lots of hills and riding the brakes for a minute and then let go of the brake to let them cool down, I start hearing a clicking/scratching noise that speeds up with the vehicle speed coming from the one of the wheels. It STOPS when I put the brakes on. Other times, the left front wheel just squeals sometimes, but the car stops fine and I was told it was fine. When it was making the noise, I pulled over as soon as I was able to pull over and then checked the brakes/wheels. The brakes were obviously hot and I could smell a tiny bit of brake dust (I just put my hand near the wheel) but not so hot that I got burned (like what happened when I had a stuck caliper last year as that same wheel was smoking and I could not within a foot of it without getting burned. Had caliper + hose + pads replaced and that fixed it). I continued on and it stopped completely until many miles later when I was on more steep hills, and then it stopped as soon as the brakes cooled. I looked at the pad through the wheel and it looked fine. I just had a wheel bearing replaced about 2 months ago on the front left.

What is even more confusing is that it only happens on hills when the brakes get really heated up. It DOES NOT happen on highways (I can drive at high speeds and hit the brakes many times and it won't do it). What could be the problem here? It is obviously heat related since it only happens in conditions when the brakes are the only thing keeping the car in control (sometimes I downshift, but not that often because brakes are easier to fix than a transmission) and they heat up.


The same noise happened again today in almost the same place on the same set of hills (actually earlier). But now I have reason to believe it is coming from one of the rear wheels, possibly the left. I was riding the brakes on the hills and then it started making a metal on metal scraping noise when the brakes were released. Once I hit the brakes it stopped, but after a while it didn't stop when I hit the brakes (it was just 90% muted, but I could still hear it with the window open). I stopped to check the brakes as soon as I was on flat ground at an empty intersection with a stop sign. All were fine and they were only a bit hotter than usual. Not burning. After sitting for one minute, I continued and the noise was about 25% of what it was. After a while of not using the brakes, it was gone completely. Then when I hit another steep hills, it started again and then stopped once I didn't use the brakes for while and coasted. It seems to be heat related. Once I ride the brakes, a non-moving part expands and hits a moving part like the rotor or the other way around (rotor hitting something). I know the right rear backing plate has a hole in it (exposing the rotor), but I don't think that is where the noise is. Could this be a backing plate issue somehow? I know the front ones are fine and were checked twice with no faults found. The rear ones are due to be checked, but what should I be looking for? Would a bent backing plate cause this? My suspicion is that the backing plate is already close to the rotor and when I drive in the mountains going downhill, the brake temperatures are going much higher than normal and then the temps cause the backing plate to either bend or expand and then cause it to strike the rotor. It is a click-click-click-click- sound that sounds metallic. Consistent pitch and volume, frequency of the clicks increases with vehicle speed. The brakes themselves look fine and there are shims installed. I don't think the calipers are sticking (just replaced a year ago. Pads are good also.).

I do appreciate any suggestions or advice. I am going away for the summer next Friday and I will be driving in the mountains every weekend on my way to or from the place where I am working all summer. I cannot get any repairs done until August after Friday, so I really need to solve this. I am doing an oil change myself and having the coolant changed this week (and having the brakes checked, but I would like to say what to look for so I am not told to re-replace a part that doesn't need replacing.).

 

You've already posted this in another thread. Please edit the existing thread instead of starting a new one on the same topic.

https://blazerforum.com/forum/steeri...hen-hot-59046/

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