XT Brakes. No power and screeching

coolatt · 05-31-2012, 10:57 PM

I feel like I am in backwards world. I have a set of the new style shimano xt brakes. They have been working great up until the other day. The rear lost all power and is making some screeching noises, I mean various pitches and noise levels and this is just on the street in front of my house on a dry day. I cleaned the rotor with alcohol and lightly sanded the pads (metal pads), no go. I then put in a new set of pads I had stashed away (resin), no go. I then put on a new rotor and still no power with loud screeching.

I then put on an elixir brake with new pads and they are perfect. WTF

Any idea what happened? The pads are aligned perfectly with no disc flex. Also the front ones are still fine with the metal pads.

hydrolmn · 05-31-2012, 11:44 PM

Did you clean rotors again after putting in new pads. Could have residue from o old pads.

Rizzle · 06-01-2012, 12:05 AM

I'm pretty sure I read on mtbr theres an issue with the brake hose/crimp fitting near the caliper, in that some lines weren't crimped good enough. Check there for wet spots/collecting dust. I recall theres a replacement available to fix it if this is the case.

leggatt · 06-01-2012, 12:16 AM

Quote:

Originally Posted by Rizzle

I'm pretty sure I read on mtbr theres an issue with the brake hose/crimp fitting near the caliper, in that some lines weren't crimped good enough. Check there for wet spots/collecting dust. I recall theres a replacement available to fix it if this is the case.

This. I have the new XTR brakes which are essentially the same. I checked my hose as I had contaminated front and rear pads without ever bleeding the brakes, so there was no way I could have gotten oil on them.

I don't appear to have leaky hoses, but also the bleed port/nipple can be replaced with a set screw type fitting. If the XT has that option, swap it out. A friend of mine had the exact same issue and we figured if it wasn't the hose, it is possible the nipple was weeping oil.

It has been a month with no issues.

kim · 06-01-2012, 02:39 PM

I had the same issue with my xts I tryed to clean them with alchol ,But had to change the pads

Oldfart · 06-01-2012, 05:44 PM

My new XT's seemed to work only after they were heated up a bit. Replaced the non finned metal pads with the finned metal ones and they are now awesome. Must have been contaminated with something. I have XTR trail on my hardtail and they are phenomenal. Although they both have a screw of mystery. the screw purportedly is a pad contact adjustement that apparently does nothing.

Duncan · 06-01-2012, 07:02 PM

I had Shimano M446 on my brand new XC bike. Rear brake screeched and shuddered almost from the get-go. Took it back to the store 4 times for pad cleaning/pad replacement/fix/adjustment. They finally just replaced it with an Avid Juicy 3. Front one is fine, so far.

Bryce · 06-01-2012, 07:42 PM

for decontaminating pads/rotors, brake cleaner works a lot better than alcohol. Just watch that you don't get it on hub seals.

PUNKY · 06-01-2012, 08:07 PM

Get some metal sandpaper. Remove pads and rotors. Sand both. Brake cleaner on both. Rinse with water. Rubbing alcohol on the rotors and pads. Reinstall. Ride!

coolatt · 06-01-2012, 08:56 PM

Quote:

for decontaminating pads/rotors, brake cleaner works a lot better than alcohol. Just watch that you don't get it on hub seals.

Quote:

Get some metal sandpaper. Remove pads and rotors. Sand both. Brake cleaner on both. Rinse with water. Rubbing alcohol on the rotors and pads. Reinstall. Ride!

Quote:

This. I have the new XTR brakes which are essentially the same. I checked my hose as I had contaminated front and rear pads without ever bleeding the brakes, so there was no way I could have gotten oil on them.

I don't appear to have leaky hoses, but also the bleed port/nipple can be replaced with a set screw type fitting. If the XT has that option, swap it out. A friend of mine had the exact same issue and we figured if it wasn't the hose, it is possible the nipple was weeping oil.

It has been a month with no issues.

Thanks, I'll try the brake cleaner first and then look in to the weepy brake line.

Tuumbaq · 06-02-2012, 08:17 PM

Ive actually had better results with isopropyl alcohol than brake cleaner... not sure why but every time I try the "real stuff" it doesnt work as well as alcohol for me.

Sounds to me like the OP might have forgotten to clean the rotor as well and contaminated the new pads...

sand, clean, re-install first and THEN start looking into more serious issues if the brakes are still not a 100%...You could also try burning the pads until no more smokes comes out...either on the oven or with a blow torch if you have one.

switch · 06-05-2012, 06:57 AM

I got some XT brakes, which I've ridden once. They squeal like a Banshee. Not happy.

Oldfart · 06-05-2012, 05:24 PM

Mine are pretty much silent. I get the odd squeal when wet or after a cleaning sometimes. Otherwise silent. Carbon frame?

biggles604 · 06-05-2012, 06:22 PM

I got a bit of squealing when I installed metal pads over the stock resins.

coolatt · 06-05-2012, 07:43 PM

Quote:

Originally Posted by biggles604

I got a bit of squealing when I installed metal pads over the stock resins.

what's the stopping power like on the resin pads?

05-31-2012, 10:57 PM	#1
coolatt Registered User Join Date: Sep 2004 Location: I'm over here Posts: 866 Rep Power: 169258	XT Brakes. No power and screeching I feel like I am in backwards world. I have a set of the new style shimano xt brakes. They have been working great up until the other day. The rear lost all power and is making some screeching noises, I mean various pitches and noise levels and this is just on the street in front of my house on a dry day. I cleaned the rotor with alcohol and lightly sanded the pads (metal pads), no go. I then put in a new set of pads I had stashed away (resin), no go. I then put on a new rotor and still no power with loud screeching. I then put on an elixir brake with new pads and they are perfect. WTF Any idea what happened? The pads are aligned perfectly with no disc flex. Also the front ones are still fine with the metal pads.

06-01-2012, 05:44 PM	#6
Oldfart Registered User Join Date: Jun 2003 Location: Whistler Posts: 4,422 Rep Power: 3542253	My new XT's seemed to work only after they were heated up a bit. Replaced the non finned metal pads with the finned metal ones and they are now awesome. Must have been contaminated with something. I have XTR trail on my hardtail and they are phenomenal. Although they both have a screw of mystery. the screw purportedly is a pad contact adjustement that apparently does nothing. __________________ Debate? Bikes are made for riding not pushing.

06-01-2012, 07:02 PM	#7
Duncan My name is not nousefora Join Date: Sep 2003 Location: ,Location,Location Posts: 4,000 Rep Power: 12251799	I had Shimano M446 on my brand new XC bike. Rear brake screeched and shuddered almost from the get-go. Took it back to the store 4 times for pad cleaning/pad replacement/fix/adjustment. They finally just replaced it with an Avid Juicy 3. Front one is fine, so far. __________________ WHEN YOU'RE A MAN...SOMETIMES YOU WEAR STRETCHY PANTS...

06-05-2012, 05:24 PM	#13
Oldfart Registered User Join Date: Jun 2003 Location: Whistler Posts: 4,422 Rep Power: 3542253	Mine are pretty much silent. I get the odd squeal when wet or after a cleaning sometimes. Otherwise silent. Carbon frame? __________________ Debate? Bikes are made for riding not pushing.

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05-31-2012, 11:44 PM	#2
hydrolmn Registered User Join Date: Mar 2008 Posts: 62 Rep Power: 0	Did you clean rotors again after putting in new pads. Could have residue from o old pads.

06-01-2012, 12:05 AM	#3
Rizzle Registered User Join Date: Mar 2011 Posts: 26 Rep Power: 0	I'm pretty sure I read on mtbr theres an issue with the brake hose/crimp fitting near the caliper, in that some lines weren't crimped good enough. Check there for wet spots/collecting dust. I recall theres a replacement available to fix it if this is the case.

06-01-2012, 02:39 PM	#5
kim The Loam Ranger Join Date: Jan 2005 Location: aldergrove B.C. Posts: 1,153 Rep Power: 60844	I had the same issue with my xts I tryed to clean them with alchol ,But had to change the pads

06-01-2012, 07:42 PM	#8
Bryce Registered Abuser Join Date: Nov 2002 Location: high as f%*k Posts: 7,036 Rep Power: 3206911	for decontaminating pads/rotors, brake cleaner works a lot better than alcohol. Just watch that you don't get it on hub seals.

06-02-2012, 08:17 PM	#11
Tuumbaq Registered User Join Date: Oct 2004 Location: squamish Posts: 425 Rep Power: 55674	Ive actually had better results with isopropyl alcohol than brake cleaner... not sure why but every time I try the "real stuff" it doesnt work as well as alcohol for me. Sounds to me like the OP might have forgotten to clean the rotor as well and contaminated the new pads... sand, clean, re-install first and THEN start looking into more serious issues if the brakes are still not a 100%...You could also try burning the pads until no more smokes comes out...either on the oven or with a blow torch if you have one.

06-05-2012, 06:57 AM	#12
switch two foot hucker Join Date: Nov 2002 Location: Old Buck Posts: 30,214 Rep Power: 15335295	I got some XT brakes, which I've ridden once. They squeal like a Banshee. Not happy.

06-05-2012, 06:22 PM	#14
biggles604 Registered User Join Date: Aug 2003 Posts: 11,512 Rep Power: 6073796	I got a bit of squealing when I installed metal pads over the stock resins.