Please help me identify source of brake noise

[dprocket]

I am working on a 2002 Mercury Mountaineer, V6-FlexFuel AWD.

This wekeend, I replaced the rear brake pads and rotors. Also, the parking brakes on both sides were completely shot. I also replaced the parking brake pads. This is the first time I've done this on this style of parking brake. I had a heckuva time getting those springs attached, but I got it done. (is there any recommended tool that makes process easier???)

Upon completion, I took the car for a test drive and noticed that there is a loud "scraping" sound coming from rear driver side.

After listening to this I ascertained that the caliper must not be releasing and probably needed to be replaced.

Next, I bled the brake lines with new fluid and did another test drive. Same result (I was hoping that the old, gunky brake fluid may have been interfering wiht the caliper and that would resolve the issue).

Next, I replaced the driver side caliper. When I was replacing it, I did notice that the inside (piston side) brake pad seemed "stuck" to the rotor, but everything else looked like it was in order: the rotor and pads looked good, the brake line bled fine (did not appear to have any obstructions in the brake line), there was not any excessive wear or destruction of either pads or rotor. Everything is still new.

After installation of the new caliper, I went for another test drive. Same issue. Loud scraping on the rear, driver side. It seems to let up when I turn left/bear left, and when I go straight, bear/turn right, it comes back.

Since the pads, rotor, caliper are all new, I now suspect that it's a problem with the parking brake pads.

Is it possible these are not installed correctly? Perhaps not adjusted properly? Maybe, the pads are not aligned properly so they are rubbing on the rotor all the time? Does this make sense? (NOTE: I have ensured that I am not driving with the parking brake engaged.)

What other steps should I take to troubleshoot? I considered going back in and just removing the parking brake pads from the driver side, reassembling to see if it goes away. Is there any safety concern to doing this? (I don't even think I need these pads for driving.) If the sound goes away, it would confirm they were what was creating the scraping noise.

Any other suggestions? I'm almost at my wit's end!

 

[swshawaii]

After installation of the new caliper, I went for another test drive. Same issue. Loud scraping on the rear, driver side. It seems to let up when I turn left/bear left, and when I go straight, bear/turn right, it comes back.

Sounds like common hub bearing failure on the Gen 3. Providing your new parking brake shoes are installed correctly, and you've ruled out rear differential noise, search "rear wheel bearings" in this stock 2002-05 sub forum. You'll find 14 pages of related threads. I gather from reading, replacement requires a MEGA ton press unless the entire hub is replaced. GL

 

[Number4]

When you apply the emergency brakes, does the pedal go to the floor, or is there resistance pretty quick?

 

[dprocket]

When you apply the emergency brakes, does the pedal go to the floor, or is there resistance pretty quick?

There is normal resistance. It it is not difficult to push it to the floor, but it does require you to push it.

 

[Number4]

There is normal resistance. It it is not difficult to push it to the floor, but it does require you to push it.

If you can get the pedal to the floor, then the shoe's aren't spread out as far as they should/could be. This should also mean they aren't scraping on the rotor. Did you pop the metal plug out of the backing plate to gain access to the star adjuster?

 

[dprocket]

If you can get the pedal to the floor, then the shoe's aren't spread out as far as they should/could be. This should also mean they aren't scraping on the rotor. Did you pop the metal plug out of the backing plate to gain access to the star adjuster?

I'm not sure what you mean by "pop the metal plug out", however when I changed the parking brake pads, I also changed out the bar with the star adjuster on it. I'm not sure I have it adjusted properly, but what you say makes sense.

 

[Number4]

The backing plate has a knock-out plug, like on metal electrical boxes. With the plug out you can adjust the shoes with everything assembled. When knocking it out, the backing plate can get mangled and rub on the rotor. Not your issue.

If it's loud scraping sound as you describe, then taking things apart, look for a shiny metal spot. No shiny spot, issue is somewhere else, unless it's the bearing as mentioned.

 

[swshawaii]

^
http://www.explorerforum.com/forums/showpost.php?p=3151228&postcount=10

 

[dprocket]

The backing plate has a knock-out plug, like on metal electrical boxes. With the plug out you can adjust the shoes with everything assembled. When knocking it out, the backing plate can get mangled and rub on the rotor. Not your issue.

If it's loud scraping sound as you describe, then taking things apart, look for a shiny metal spot. No shiny spot, issue is somewhere else, unless it's the bearing as mentioned.

Thanks for the help, folks. I took it to a local shop, and it turns out it was the bearing. Appears to be resolved now.