Loud grinding noise when braking.

Nontechgirl · Post by **Nontechgirl** » 02 May 2016, 18:25

Hi!

I am hoping I can get some advice here. I have a 1995 850. About a year ago, I suddenly had a loud grinding noise coming from my brakes. It only happened in hot weather and when the brakes seemed to be hot. Also, it only happened when I was coming to a final stop, like the last 10-20 feet. I took my car to my "trusted" mechanic. They diagnosed it as being my front pads and rotors, so they replaced them (they also felt the front vibrating.) When I got the car back from them, the same noise was happening! So, I took the car back to them. They kept it for the whole day and said, they didn't hear anything? They said they checked everything, including the calipers, and said everything is fine and the brakes are working well. So yeah, NOW the brakes seemed okay after I got it back the second time. I know they did something to fix it, but they denied it ever happening, so I have no clue what they did to fix it.

When I got the car back, the weather was starting to cool since it was nearing winter (Aug/Sept. 2015). My winter weather is like 70's during the day, and during this time, there was no grinding. It's now starting to get hot again, and sure enough, that grinding noise is back, but not as bad as the first time a year ago. Again, it is only when the brakes heat up and I come to a final stop. If I break lightly, it won't make that noise, and it takes me driving for about 15 minutes for the grinding noise to start (it sounds like metal on metal.) Also, I don't feel the vibration like I did a year ago. I only drive the streets, and have not been on the freeway since I got the new brakes.

I need help because I really don't want to go back to that mechanic if I don't have to. Could it be the pads needs breaking in, or did they put cheap pads on? Should I go back to them? I want to be prepared in case they tell me again they "didn't hear anything." I'm assuming there is some kind of warranty?

I've been searching the web for several days now, and really haven't found an answer except for, it might be from cheap pads.

Any advice will be greatly appreciated!

Thanks!

Post by **matthew1** » 02 May 2016, 18:34

Try bending the dust shield to a different position. You can do it with your hands with the wheels on the car.

Post by **polskamafia mjl** » 02 May 2016, 18:42

Is it a grinding sound or a squealing sound? Squealing is common on these cars and usually pretty simple to fix.

Nontechgirl · Post by **Nontechgirl** » 02 May 2016, 18:54

It's a grinding noise - loud! Like a big semi truck.

Nontechgirl · Post by **Nontechgirl** » 02 May 2016, 18:56

Thank you Matthew1! I will have my new mechanic take a look at that.

Post by **polskamafia mjl** » 03 May 2016, 00:23

You can bend the dust shields back yourself, you don't need to have a mechanic do that. If its not the pads I wonder if a failing wheel bearing could grind as it heats up. I've never dealt with a bad bearing so I can't say from personal experience.

Nontechgirl · Post by **Nontechgirl** » 03 May 2016, 01:27

Thank you for your response, polskamafia. I have to take my car in to have the brake lines replaced, so I am going to have them check the dust shield. I just Googled about wheel bearings, and it doesn't sound like that is the problem. So, I can check that one off of the list.

Post by **850 LPT** » 03 May 2016, 07:55

Hi there, did your mechanic ever check the rear brakes?

See if you can tell where the noise is coming from, either front or rear. Also, checking the pad thickness is real easy once the wheel is off.

Post by **abscate** » 03 May 2016, 09:21

If you put new pads onto old rotors (which is fine to do) sometimes the 'edge' on the rotor will make noise as it warms up. This is annoying but does not change brake function.

It is easy to mistake front/rear brake noise, too.

One last thing to check - get a flashlight and look at both sides of both brake rotors. Its possible for calipers (squeeze the brake pads) to freeze up on one side, which will make the rotor on that side rough...Ill post some pictures below. Eventually the pads wear and kill the rotor if this happens. The rotors should look like shiny metal on both sides after you drive home from the work/play/protest march/whatever.

Nontechgirl · Post by **Nontechgirl** » 03 May 2016, 11:33

Thank you to all of you. I will have all of these things checked out. The rotors are new on the front and the back ones look good. I never thought about the noise might be coming form the rear brakes, so I will have them checked too.