brake noises - rotors at service limit?

[DR1665]

Ironic to start the gen 2 troubleshooting sub with a question about stopping, but whatever.

My front brakes started making noise the week before MOD. As in, it sounded like the feeler was making contact while moving (read: not touching the brakes). Short on time, I simply replaced the pads.

I know, I know. And, for some reason, I always hear Ryan's voice in my head reminding me I need to get the rotors checked and turned if I'm gonna do it right. But "doing it right," to me anyway, means upgrading to braided lines, speed bleeders, drilled rotors, and manual hubs. (I'd also like to replace the UCA bushings, died-within-a-year Mevotech ball UBJs, and maybe lay down a fresh coat of paint while I'm in there, but I digress.)

Within 24 hours, the front brakes were making the exact same noise. That shrill, hissing, metal-on-metal sound that makes even the finest machine feel like a complete piece of shit. Again, I digress.

Yesterday morning, I replaced all four guide bolts on the front calipers with new units from NAPA. I removed the pads, flushed the bolt holes with WD40 until it ran clear, then flushed with brake cleaner until that ran clean. I let things air dry before chasing the threads with the new bolts—all the way and back out twice—before reinstalling the pads with new clips, and greasing the new bolts with the highly recommended Syl-GLide, silicone brake parts lubricant. I applied a thin coat of this to the back of the pads, too.

The brakes STILL make noise while driving. WTF?

Fezzik stops just fine, but I notice when I squeeze the pedal (like when you have to stop shorter than expected—not even what I'd call threshold braking), the front brakes make a grumbling, almost crunchy sound.

I'm thinking, considering the PO put 160k+ on the original timing belt—and rounded off the upper guide bolt head on the driver's side caliper, AND removed the CEL & SRS lights before selling the truck—it's also likely these are the original rotors. I don't have the right kind of mic/calipers to check rotor thickness correctly, and I'd rather replace the alternator next, but I'm hoping someone here will be able to say, "Oh yeah. Without a doubt. You need new rotors."

Thanks in advance.

[Crumb]

 Maybe your rears are making the noise?

[DR1665]

Maybe your rears are making the noise?

Pretty sure it's the front--but not gun-in-the-face sure. I'll have to get a spotter and report back.

Thanks!

[Crumb]

 I've chased noises that ended up being in a different place than I thought.

[PA_JERO]

Definitely check the back like adam said. One other issue I've seen is front wheel bearings. If your wheel bearings are either shot or maybe with luck on your side, need to just be cleaned and repacked. When the caliper applies pressure on the rotor, it can pull the rotor into the caliper bracket and make an aweful grinding noise. Best way to check your bearings. Jack up the truck and push the top of the tire in and out or back and forth to feel any play or slop in the wheel/hub. I will say though, new or fresh rotors kicks a ton of ass and that should really be considered. Way worth the money and work.

[PajEvo]

Agreed with all above. Esp the mysterious nature of Montero noises. They're like ninjas.

Its getting harder to find a shop to have rotors turned these days. Seems no one wants to save anything anymore?

[concealer404]

Plenty of places around here will turn rotors.  At $20 a pop.  Makes better financial sense to buy new ones, scrap the old ones, and not have to drive around with some dirty rotors in your truck back and forth to have them turned.

[RyanY]

You can get usually get a pretty decent idea of the rotor thickness by seeing what size open-end wrench will fit over the edge of it. It's not as accurate as calipers but it'll get you in the ballpark.

[DR1665]

This just in from the spotter: it is, in fact, the rears.

I think they're drum-in-rotor? Further testing reveals the noise is constant while I'm motion. Slight pedal pressure silences them, but pulling on the ebrake does nothing. I'm thinking pads, not shoes. Anyone concur?

(Manual hubs and a brake upgrade are coming by spring.)

[PA_JERO]

The shoes in the ebrake set up rarely ever go bad. So yes, pads for the win. You may be in the market for new rotors now. And there is some pretty solid deals on rock auto for rotors.

[Canyonero]

And the rear rotors are much less of a PITA to change than the fronts.

[RaptorReed]

I get the opportunity to change the front rotors on mine lol. Need to double check it isn't the hub that caused things to go awry.

[jaccox]

Rear rotor and pad change is a cake walk and like Pajero pointed out there are some good deals on Rock Auto. I think somewhere in the ballpark of 70ish doll hairs and you'll be all spiffy for a long time

[PA_JERO]

You could get totally crazy on all this too while your at it. I just recently put , on all 4 corners, slotted rotors, carbon fiber pads, and all rubber lines replaced with stainless brake lines. I'm pretty happy with the stopping power of my brakes these days. I also rebuilt all my calipers while I did all that, so let me save you like 5 dollars and about 8 hours of your life. IT'S NOT WORTH THE TIME. Rebuilding calipers really really sucks. If you need to go as far as caliper replacement. Just buy rebuilt calipers that are on rock auto ready to go, I won't ever do it again.

Let's just say this, if you do it the way you want it now, it saves you from doing it twice, and is easy on your wallet down the road. It's taken me 15 years to learn this about my habit/hobby.

[RyanY]

Let's just say this, if you do it the way you want it now, it saves you from doing it twice, and is easy on your wallet down the road. It's taken me 15 years to learn this about my habit/hobby.

I'm right there with you on this. It's been hammered home to me too many times in the past when some part I replaced just a couple years ago has failed again because I cheaped out and bought the least expensive part I could find. My time is way too limited to be wasting it doing repairs multiple times, so I bite the bullet and pretty much only buy OEM parts for all of my vehicles any more.