new brakes are grinding

I just put on new rotors, and pads last week. I now have this horrible grinding noise when I come to a complete stop. I am not sure what it could be. I pulled everything off looking for grooves and uneven ware, but found nothing. I have iscolated it to the brakes as is doesnt grind after i spray it down with brake cleaner. But as soon as the brake cleaner wears off then its back to the grinding. I suppose that it could be a bad combination of pads and rotors, but i ran a straight edge around the surface of the rotors and found no inconsistancies. The pads themselves are mettallic, and looked to be without imperfections. I am at a loss with where to go from here. Has anyone had this experience with grinding brakes after installation?

2000 4.0 D30 Autozone brakes and rotors.

Thanks
Ben

help please

Please don't bump threads.

Re: the brakes: it sounds supiciously like you've got a set of bad or incompatible pads. Pull them and check for cracks. Is the grinding coming from one or both sides?

FWIW, the 2000s used two different types of rotors: composite and steel. IIRC, the steel rotors have a backspacing of 3-1/16"; composites are 3-3/16". While one will noticeably not fit the other, it's possible that you got the right backspacing but wrong disc material - I've heard of this happening before, but have never experienced it firsthand so take it for what it's worth.

It might just be the pad. Please take no offense, but private label pad or low end pads tend to be a very hard friction material and can cause brake noise. I have had hit or miss luck with private label pads.

On our SCCA race cars the race pads are very hard in order to last and they make tons of noise until you get the tempeture up. It would take one or two laps to get them up to the right temp but then they would always make some noise. They would also eat through rotors quick.

Does your noise change the hotter the brakes get?

Edit: Also it will take a few miles for the pads to seat.

casm said:

Please don't bump threads.

Re: the brakes: it sounds supiciously like you've got a set of bad or incompatible pads. Pull them and check for cracks. Is the grinding coming from one or both sides?

FWIW, the 2000s used two different types of rotors: composite and steel. IIRC, the steel rotors have a backspacing of 3-1/16"; composites are 3-3/16". While one will noticeably not fit the other, it's possible that you got the right backspacing but wrong disc material - I've heard of this happening before, but have never experienced it firsthand so take it for what it's worth.

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It is hard to locate but it feels like it is coming more from the P/S. I have steel rotors at 3 1/16". I have pulled the pads and found no cracks.
What do you mean by bumping threads. Is there a rule out there that I dont know about.

00Classic said:

It might just be the pad. Please take no offense, but private label pad or low end pads tend to be a very hard friction material and can cause brake noise. I have had hit or miss luck with private label pads.

On our SCCA race cars the race pads are very hard in order to last and they make tons of noise until you get the tempeture up. It would take one or two laps to get them up to the right temp but then they would always make some noise. They would also eat through rotors quick.

Does your noise change the hotter the brakes get?

Edit: Also it will take a few miles for the pads to seat.

Click to expand...

I am leaning towards incompatible pads with the steel rotors. Yes it does seem to get better after the brakes become hotter.

old_man said:

OK first, bumping threads is frowned upon. That said, do a compression check both wet and dry and post the numbers back here.

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Sorry didnt know about bumping threads.

bholt5035 said:

It is hard to locate but it feels like it is coming more from the P/S.

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P/S meaning power steering? Sorry if I sound like I'm being pedantic, but I want to be sure we're on the same page here. Also, if power steering is correct, do you mean that the sound is coming from the brakes and there's a shake in the steering that goes along with it or is it something else?

I have steel rotors at 3 1/16". I have pulled the pads and found no cracks.

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I'm still going to go with the pads being suspect for now; from the info we've got so far they seem like the most likely culprits.

Oh, the discs - what brand were they, and did you have them machined before fitting them or not? Also, do you have ABS?

I would say its the pads/rotors. I work at a Jeep Dealer and we have got NAPA rotors that pulsated worse new than the old warped ones we were replacing.

P/S passenger side. its got to be the pads. changing them tomorrow. will post up with results.

Did you do the brake job? Did you notice one side's pair of pads worn more than the other? It could be that a calipher is sticking. It could be internal of the calipher or the calipher bolts or guiderails. If its both brakes, then you might also look at the master cylinder. The noise coming from one side, would make me think its not just the pads/rotors. I would look for a warped rotor though. See if there are any high spots. Also, possible check the bearing on that side.
Tom