Brake squeal help.

TommyF

Active Member
I replaced the pads in my XTR brakes, put in what I took out which were J04C Shimano metal pads. Cleaned up everything with isopropyl alcohol, including a wipe down of the rotor and pads. Did a little bedding in and off to the trails. They were fine for the first 1 or 2 rides, since then they howl like crazy when applied. I blamed it on the humidity, but I'm realizing that isn't really the case. Any ideas on how I can quiet these things down? I've read about people baking them to remove contaminants, sanding them, soaking them in brake clean etc. I've checked the caliper alignment and just this afternoon sanded them lightly and cleaned them up AGAIN. This only happens with the front brakes, the rears are perfectly silent. What's my next step to quiet them down???? The good part is that every hiker I've approached hears me coming and every wild animal in the woods runs away as I approach. The bad is they are annoying both to me and anybody I'm riding with. Stopping power seems fine.
 

shrpshtr325

Infinite Source of Sarcasm
Team MTBNJ Halter's
does your rotor say anything about resin pad only? some do and using metallic pads with them causes noise. (its possible your rotors arent the same too)
 

Magic

Formerly 1sh0t1b33r
Team MTBNJ Halter's
Did you do any bleeding where something may have gotten onto the pads? The rotors are usually easy enough to clean with brake clean (off the bike), but the only thing that ever worked for me for pads was waving a blowtorch over the pads to burn/boil contaminants off. Just make sure you don't just sit there burning the shit of out them so you don't mess up the glue holding them to the back plate. Other than that, once it squeals, it's usually hard to get rid of without replacing both together.

I prefer metallic pads and stopped using Icetech's a while ago. Icetech's have aluminum sandwiched in them and the metallic would eat the rotor faster than a resin pad. The Icetech rotors also seemed to glaze over quickly compared to Ai2 or Centerline. I think resin is typically quieter too. I run metallic pads with Ashima Ai2's on pretty much all of my bikes.
 
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MadisonDan

Well-Known Member
Team MTBNJ Halter's
pretty much all of my bikes.
1626809442501.gif
 

TommyF

Active Member
does your rotor say anything about resin pad only? some do and using metallic pads with them causes noise. (its possible your rotors arent the same too)
Original rotors on the bike and the pads I took out (same went back in) never made any nose.
 

TommyF

Active Member
Did you do any bleeding where something may have gotten onto the pads? The rotors are usually easy enough to clean with brake clean (off the bike), but the only thing that ever worked for me for pads was waving a blowtorch over the pads to burn/boil contaminants off. Just make sure you don't just sit there burning the shit of out them so you don't mess up the glue holding them to the back plate. Other than that, once it squeals, it's usually hard to get rid of without replacing both together.

I prefer metallic pads and stopped using Icetech's a while ago. Icetech's have aluminum sandwiched in them and the metallic would eat the rotor faster than a resin pad. I think resin is typically quieter too. I run metallic pads with Ashima Ai2's on pretty much all of my bikes.
No bleeding was done, the blowtorch might be my next step.
 

ebarker9

Well-Known Member
Sounds like you've done most of the logical things. My general observation is that all brakes can randomly suck for seemingly no good reason. "Contamination" is always the suggested culprit, but I've very much gone through this process where there's no bleed involved. Clean the caliper with isopropyl alcohol before install. Wear disposable gloves. Go through normal bed-in process and either the pads have zero bite to them or they make a horrendous racket.

:shrug:
 

TommyF

Active Member
@ebarker9 - That's where I'm at as of now. Interesting part is I had purchased 2 sets, same supplier, the rear is silent and bites hard, the front however is a screamer !!!!
 

Frank

Sasquatch
I never use brakleen on my bikes, only Simple Green, wash, rinse and let dry. Every time is used brakleen it would howl.
 

Karate Monkey

Well-Known Member
BTW: don't cross-contaminate stuff; clean the rotor with one rag, clean the caliper (especially the insides/around the bleed port) with another. +90% IPA is the desired stuff for Shimano; push the pistons out slightly more than they are, clean around with q-tips/pipe cleaners, then push back in and finish the insides; clean the outside of the caliper with the same, use soapy water if necessary to clean build up. Actuate the brake, and check for even piston movement; if pistons do not move equally, take a 4 piston bleed block, shave the sides down flush, and grind through ONE QUARTER of the block, halfway to the brake pad retaining pin (imagine: one side of the block L/R remains untouched. Following the imaginary centerline, remove one quadrant of the pad up to that point). Insert your prepared block into the caliper, and use it to extend one piston--clean, dry, lubricate with mineral oil, press back in--at a time, moving the block through the top/bottom, rotating as needed to exercise/lubricate all the pistons. When done, wipe down the insides with IPA to remove any remaining surface oil.

I never clean rotors unless there is something wrong with them, and I encourage others to do the same. When replacing pads with identical compound, no cleaning/roughing is necessary, but if you switch makes/compounds, you need to use 120-240 grit paper to remove the bedded in materials, which can cause squealing with the different compounds.

Check the braking surface of the pads--if dark/discolored, and a quick buff on sandpaper does not restore them to their original color, there is some kind of contaminant on them (check your fork leg for seeping oil on the bottom). Brake rotors may also have something to do with it, but that's harder to pin down. If they are discolored (bluish instead of bright silver), it can indicate heat that could have glazed them/the pads. Clean using a folded piece of 240 sandpaper, trying to maintain consistent pressure.
 

TommyF

Active Member
@Karate Monkey - Excellent advise !!! Update on todays ride. I sanded and cleaned them up at lunch time then went on the Cycle Craft Tourne ride after work. They were nice and quiet for that ride. Lets see how they behave after a few more rides. Fingers crossed.....
 

MadisonDan

Well-Known Member
Team MTBNJ Halter's
BTW: don't cross-contaminate stuff; clean the rotor with one rag, clean the caliper (especially the insides/around the bleed port) with another. +90% IPA is the desired stuff for Shimano; push the pistons out slightly more than they are, clean around with q-tips/pipe cleaners, then push back in and finish the insides; clean the outside of the caliper with the same, use soapy water if necessary to clean build up. Actuate the brake, and check for even piston movement; if pistons do not move equally, take a 4 piston bleed block, shave the sides down flush, and grind through ONE QUARTER of the block, halfway to the brake pad retaining pin (imagine: one side of the block L/R remains untouched. Following the imaginary centerline, remove one quadrant of the pad up to that point). Insert your prepared block into the caliper, and use it to extend one piston--clean, dry, lubricate with mineral oil, press back in--at a time, moving the block through the top/bottom, rotating as needed to exercise/lubricate all the pistons. When done, wipe down the insides with IPA to remove any remaining surface oil.

I never clean rotors unless there is something wrong with them, and I encourage others to do the same. When replacing pads with identical compound, no cleaning/roughing is necessary, but if you switch makes/compounds, you need to use 120-240 grit paper to remove the bedded in materials, which can cause squealing with the different compounds.

Check the braking surface of the pads--if dark/discolored, and a quick buff on sandpaper does not restore them to their original color, there is some kind of contaminant on them (check your fork leg for seeping oil on the bottom). Brake rotors may also have something to do with it, but that's harder to pin down. If they are discolored (bluish instead of bright silver), it can indicate heat that could have glazed them/the pads. Clean using a folded piece of 240 sandpaper, trying to maintain consistent pressure.
That seems like a metric fuck ton of twerk.
@Magic ’s solution of just not riding seems way moar betterererer.
:p
 
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