View Full Version : Metal to metal grinding noise intermittent in front

03-08-2017, 08:38 PM
Not sure when I started noticing this grinding noise, but it's only when coming to a stop under 10mph with normal or hard braking. However, it doesn't do it right off the bat. It takes a few stops to hear the noise. The brakes are recent and calipers were done as well. I've taken the brakes apart and regreased contact points, and as far as I know, the bearings are okay.

Any thoughts?

It could just be the brake pads. They were cheap AutoZone pads.

03-08-2017, 09:13 PM
I had one of the tabs on the anti-rattle clips bend out without realizing it when I changed pads once. Same symptoms you are describing. I pulled the caliper off to investigate and it caught my eye when I was slipping it back on over the rotor.

03-08-2017, 09:25 PM
Pull each wheel and spin the hub/rotor - if the issue is brake related, it should show up then.

If not, look for a loose lug nuts, or a cracked wheel.

sam jones
03-08-2017, 10:02 PM
Good evening

As KMT stated remove the wheels and spin to rotors. Check clearance between the hub/spindle dust shield and the rotor at the 3, 6 9 and 12 positions. Inspect the caliper alignment pins for binding/lack of lubrication.

Good Luck.

03-10-2017, 04:45 PM
I only had enough free time to check one side, but the slide bolts did show signs of lack of lubrication. So I cleaned them up and put generous amounts of lube on them. I will need to do the other side and see if it makes a difference.

03-12-2017, 08:26 PM
Assuming that the rotors were either replaced or resurfaced,I've experienced some brands of pads to be inferior when even when properly heat cycled or "seated/broken in"...Break the glaze on your rotors and try a different brand of pads...

03-18-2017, 08:46 PM
Trying another set of pads. EBC greenstuff. Just waiting on them to get here...

03-21-2017, 07:38 PM
After replacing the pads, I now feel​ it pull to the right under braking. And I'm sure the calipers aren't getting hung up. Other than getting another caliper to test, the brake hoses are original and should more than likely be replaced.

sam jones
03-21-2017, 11:09 PM
Good evening

What lubrication did you use on the caliper alignment pins?

03-21-2017, 11:49 PM
Silicone. Cleaned and lubricated all points of contact.

sam jones
03-22-2017, 12:53 AM
Good evening

Inspect the caliper(s) for an extensive "wear" grove were the pad slides back and forth causing a hanging/sticking condition. May require a file to correct. Do not forget to lube this area also.

03-22-2017, 10:18 AM
Alrighty. I will revisit those areas in question.

03-27-2017, 01:39 PM
Metal to metal sound still present, but sounds like it's coming from all over now. The pulling is from the crappy front end.

03-27-2017, 03:05 PM
sounds like it's coming from all over now.

Can you make a video you can share here with the noise?

sam jones
03-27-2017, 03:45 PM
Good morning

The grinding/scraping noise is one of the first signs of a bearing/hub impending failure since you inspected/repaired the calipers and replaced brake pads.

I know this is repetitive. Jack and support the front end. Grab the tire at the 12 and 6 o'clock position. Push and Pull. If you feel moment or a slight clicking sound the bearing/hub assembly is worn requiring replacement. Spin the tires and listen for the metal grinding sound. Since you inspected/repaired the calipers/break pads suspect bearing/hub assembly causing the noise.

Inspect the tires tread for feathering and the front suspension for possible brake pulling in one direction.

I found both front bearing/hub assembly bad on a 1991 with the same original problem you have.

Good Luck.

03-27-2017, 05:37 PM

Noise is heard at about 1:20. Other noise is the moonroof shade rattling.

sam jones
03-27-2017, 06:12 PM
Good afternoon

Provide link in error 404.

03-28-2017, 10:52 AM
Well I guess the video isn't coming up. I'm going to try the 93+ spindle set up.

03-28-2017, 11:19 AM
Did this noise show up right after doing brakes? If so, it may be the backing plate rubbing on the rotor. I would remove the rotor, and look for any signs of the scraping on the backing plate.

03-28-2017, 08:02 PM
I wish it was that simple, but I've checked the backing plates many times. Checked clearance, lubrication, slides, contact points, and bearings.

sam jones
03-28-2017, 09:57 PM
Good evening

If you have not changed to '93 hub/rotor assembly have the original the rotors been checked for run out. From AA1Car "The maximum amount of runout that is acceptable will vary somewhat from one vehicle to another, but most should have no more than .003 to .005 inches of runout. Excessive runout can be caused by runout in the hub, dirt or corrosion between the rotor and hub, or runout in the rotor itself (as a result of wear or incorrect machining)".

Also from AA1Car "Rotors sometimes develop "hard spots" that cause the rotors to wear unevenly. This usually leads to variations in rotor thickness that can make the brake pedal pulsate when the brakes are applied. Hard spots can often be seen as dark, discolored or blue-colored patches on the rotor surface. Resurfacing can restore rotor flatness, but hard spots usually return. The best repair is to replace the rotors".

If the brake attaching hardware (calipers, pads, lubrication and corrosion inspection) are good I would think the next inspection step is the rotors.

03-28-2017, 10:23 PM
sounds like it's coming from all over now.

I'm starting to wonder if this has anything at all to do with the front brakes...

Could be a cracked flexplate, badly failed motor mount, busted exhaust shield, cracked pulley, dry supercharger, failed alternator/power steering pump, loose lug nuts...who knows.

If you can't get that video working, I'd take it to a shop that won't charge first born to at least give an opinion.

03-29-2017, 03:26 PM
Flexplate... Well mine is automatic. I put new motor mounts on when the I dropped in the engine. SC has the correct amount of oil in it. P/S hasn't gone bad.

I will try rotors.

04-04-2017, 11:12 AM
It's looking like new rotors did the trick. Not sure how, but mno more noise.

04-04-2017, 01:57 PM
It's looking like new rotors did the trick. Not sure how, but mno more noise.

That's good news.

I don't know how closely you looked, but I had an issue one time where I bought new front rotors based on application, and they were slightly different from the OEM on the SC...the hat height was not the same, making the rotor itself sit in a different location compared to the mounted caliper. I ended up shopping by rotor spec instead.


04-09-2017, 10:26 PM
I lied. It took a few days, but the grind noise came back slowly along with a squeak/squeal. I'm not sure what to try next other than just doing the spindle swap. If there are better rotors, let me know. I bought AZ duralast ones.

04-09-2017, 10:53 PM
Not the current rotors, but my previous rotors were Brembos from RockAuto.

Currently I've got Wagner Advanced rotors on Ruby; she's doing good with them.

(I've got those for the Dakota; I bet I have the same problem, the caliper bracket barely rubbed on it.)