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2004 chevy trailblazer_lt
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Discussion Starter #1
Hi! So I've been fixing up the 2004 Trail Blazer LT that I had taken ownership of recently. Since I've bought it a few months ago I've noticed noise coming from near the front wheels that mostly occurs after driving through wet conditions. After replacing the front tires, tie rod ends, struts and getting an alignment done the noise has seemed to only get worse and my ABS light has been on for weeks now. I'm sure I need to replace the rotors and pads soon but I'm not sure if those are the root of the metal squealing noise that's been drilling into my brain :crazy:

I understand that it could be a handful of things causing the noise but I was hoping someone could point me in the right direction to diagnose and remedy the issue.

More about the noise;
Dampens when the brakes are applied and gone when not in motion
Doesn't really happen in reverse
The position of the steering wheel does not effect the noise
It sounds very loud and almost embarrassing when driving aside other vehicles or structures with the sound bouncing off right back at me.

Any help on this would be very much appreciated
 

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2007 chevy trailblazer_ls
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You say you need to replace the brake pads. That's what the warning tabs on the brakes telling you the pads are worn sounds like. It starts squealing when you press the pedal. As you ignore the noise the tabs wear down and it eventually starts squealing without pressing the brake and can disappear as you press the brake. Sure seems to me you need to replace the brake pads. ;)
 

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2004 chevy trailblazer_lt
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Discussion Starter #3
Thanks for your reply.

The noise dampens when the brakes are applied and is at it's worse when in drive as the wheels spin. It used to only occur during or after wet conditions but now it seems to happen all of the time.

Still think it's my brake pads? I'll lift the front end and spin the tires some time tonight. I said I'm sure I need to replace the rotors and pads soon just as general maintenance. The outside of the rotors look like they has some life left in them but between them (on the inside) shows flaking rust. I haven't bothered touching the caliper to look at the pads yet.
 

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2006 chevy trailblazer_lt_ext
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I've noticed noise coming from near the front wheels that mostly occurs after driving through wet conditions
Any help on this would be very much appreciated
Ya know, cheap aftermarket pads tend to absorb moisture and don't shed all of it. Plus the last chucklehead that slapped a set of white box AutoZone pads on it may have thrown the factory shims out. If the brakes are nearing the end of their service life, I'd go ahead an put a set of Delco pads (make sure you get the shim pack) and rotors on the front and see how it does for you.
 

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Discussion Starter #5
Ya know, cheap aftermarket pads tend to absorb moisture and don't shed all of it. Plus the last chucklehead that slapped a set of white box AutoZone pads on it may have thrown the factory shims out. If the brakes are nearing the end of their service life, I'd go ahead an put a set of Delco pads (make sure you get the shim pack) and rotors on the front and see how it does for you.
Thanks! I wouldn't expect anything less from the cheap back yard mechanic I got the car from :ugh:

I'll have a look at the pads tonight and dig into the issue further. I'll be traveling about 400 miles with the car next weekend and probably can't deal with anything until after I get back.

Looks like pricing for the pair of AC Delco rotors and pads w/ shims is around $100. Not too bad. I'll get that done and hope it fixes the noise before I loose my mind. We'll see what comes first.
 

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Hey I'm a back yard mechanic too, but at least I have the wherewithal to use service data and OEM parts. :thumbsup:
 

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...Still think it's my brake pads? ...
That's my guess and I'm sticking to it. :)I've had the same symptoms when I ignored a squeal until the tab wore down. Maybe 1,000 miles past the start. It is just a thin piece of spring metal and it can assume a different shape as it wears. It has to have an edge rubbing on the rotor to vibrate. If it wears down and forms a bowl shape, pressing the brake causes the bowl to contact but releasing causes it to lift just enough to get an edge to still rub. At least that is what happened to me. It was VERY obvious the pads needed replacing when I finally found the time.

BTW, you should be able to see the pads by simply removing the wheel. I haven't checked my TB but I can see the pad thickness on my other car without even removing the wheel.
 

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2004 chevy trailblazer_lt
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Discussion Starter #8
Hey I'm a back yard mechanic too, but at least I have the wherewithal to use service data and OEM parts. :thumbsup:
The guy was sketchy is all I mean :rolleyes: Ignored any inquiry I had about the car after the deal was done even though he offered to do repairs if needed. The more you dig, the more you see how much wasn't cared for. It was a "certified" mechanic that owned the car pretty much it's whole life. It wasn't until I looked around that I noticed he was running a shop with employees in his garage. Matching shirts and all.

Still the best used SUV I've driven while in the market.

As a freelance engineer during my spare time it's in me to do any work I can and try to do it right. You guys have been helpful and the archive of this forum is a godsend.

Thanks again. I'll report back when I have more details. Fingers crossed it's just the pads. I hear the noise going at any speed - but more so going slow.
 

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2008 gmc envoy_sle
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The guy was sketchy is all I mean :rolleyes: Ignored any inquiry I had about the car after the deal was done even though he offered to do repairs if needed. The more you dig, the more you see how much wasn't cared for. It was a "certified" mechanic that owned the car pretty much it's whole life. It wasn't until I looked around that I noticed he was running a shop with employees in his garage. Matching shirts and all.

Still the best used SUV I've driven while in the market.

As a freelance engineer during my spare time it's in me to do any work I can and try to do it right. You guys have been helpful and the archive of this forum is a godsend.

Thanks again. I'll report back when I have more details. Fingers crossed it's just the pads. I hear the noise going at any speed - but more so going slow.
front hub bearings ok?

front backing plates rubbing?
some other ideas on top of the prime suspect , brake pads.
 

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2004 chevy trailblazer_lt
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Discussion Starter #10
front hub bearings ok?

front backing plates rubbing?
some other ideas on top of the prime suspect , brake pads.
If I recall correctly the backing plate looked pretty rough/rusted. I'll put up some photos over the weekend to see if it helps identify potential problems.

I had the thought to replace all wheel bearings and backing plates. I'm not sure how far gone these parts could be.
 

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2006 chevy trailblazer_lt_ext
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Front wheel bearing noise will change when loading and unloading the suspension (I.E. during a turn or lane change), and usually be less noticeable at speeds above 35mph.

I can’t get that link to work. Says not available offline.... but I’m not offline. Must be the Russians again. :)
 

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Parts are inexpensive enough, even for Delhi brand, and the front wheel bearing job isn’t all that bad. Can’t remember the hub nut size. Why does 25mm come to mind? Might as well crack in.
 

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Parts are inexpensive enough, even for Delhi brand, and the front wheel bearing job isn’t all that bad. Can’t remember the hub nut size. Why does 25mm come to mind? Might as well crack in.
front hub is replacement is not hard at all.


I believe hub nut size is 26mm
 

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Discussion Starter #15 (Edited)
Upon further investigation...


The back side of the rotor is not in good shape as well. I think one of the metal tabs on the pad broke off and got caught in there since it's missing and the damage seems aggressive.
 

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Upon further investigation...


The back side of the rotor is not in good shape as well. I think one of the metal tabs on the pad broke off and got caught in there since it's missing and the damage seems aggressive.
ouch, make sure the metal clips are free of rust. and caliper slides smooth.

i had similar issue, but pads were nowhere near as scored as yours.

changed metal clips, backing plates
 

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Discussion Starter #18 (Edited)
The backing plates seem to be okay. It's obvious to me that the car sat around for a while (chipmunk making a home under the hood). The rotors probably got rusted out and the pads eaten away when they decided to drive it again. Also my heavy foot didn't really help anything :duh:

Will likely throw in some cheap pads in the front to get me through the week or however long I feel comfortable with them. Luckily the ACDelco GM OE front rotors and pads are still available for $160 for the set.

I'm wondering if it would be worth while to change the back rotors and pads soon as well. They don't seem to have any signs of trouble but if the fronts are this shot it might be the best thing to do for preventative maintenance. Just a thought. The GM OE back rotor doesn't seem to be available anymore though a premium version is.
 

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Discussion Starter #19
You ever take something apart and spend more time taring up your garage looking for a tool you swore you bought years ago? :suicide:
One C clamp and brake grease purchase later... Pads are installed and the noise is gone! :woot:

The best I could do was Duralast Gold pads from Autozone for under $40. Me being an amateur do it yourself guy I pressed on the brakes to see the pistons move. One of them seemed stuck. I went and pressed the loose one in place and it squirted brake fluid half way down my driveway. The passenger pads seemed to have about 70% meat left on them.

I'll have to keep an eye on things for uneven wear. So far the car stops on a dime with seemingly no issues.

Thanks for the help! I'm glad it was an inexpensive fix.
 

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KML, I'd have to recommend AC Delco parts for brakes since they're pretty safety critical components. The cheap aftermarket pads tend to absorb moisture and do not shed it readily like OEM pads would. If the rear brakes aren't giving you any problems I'd be inclined to leave them. The rear brakes only take about 20-30% of the braking load.
 
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