[splat]

I just purchased a RM Element 50. On my second ride, I started getting a loud front end rattling sound whenever I hit a bump and bouncing the front end up and down by hand also replicates the rattle sound. It appears to be coming from the Shimano BR-M525 disk brake, I checked the tightness of both the caliper and rotor, and they seem to be on tight so I really don’t know what the problem is.

Any ideas of what the problem might be before I bring the bike in for service only to possibly be told that the rattle sound is normal.

 

[EvilScience]

I have the same problem - Ideas anyone?

I have the same problem with the rear 525 discs on my 2004 RM Hammer. I had misdiagnosed the noise as a hub/cassette problem, but after a few rides it is clearly the disc setup. In addition to the rattling sound, I am now experiencing some howling brake rub as I'm riding - it doesn't seem to produce much friction, just a LOT of noise. As Splat said, everything seems tight. Comments? Ideas? Or is it just time to head to the LBS for some service?

 

[splat]

I have the same problem with the rear 525 discs on my 2004 RM Hammer. I had misdiagnosed the noise as a hub/cassette problem, but after a few rides it is clearly the disc setup. In addition to the rattling sound, I am now experiencing some howling brake rub as I'm riding - it doesn't seem to produce much friction, just a LOT of noise. /QUOTE]

Taken from the Shimano Tech Talk Newsletter 1/2001

Noise Reduction
"If you experience a rattling noise on BR-M755 or BR-M555, just take off the pad spring and bend the spring ends a little outward in order to give spring a little more tension."

Well, my LBS tried this fix and it made no difference whatsoever. They even contacted Shimano Canada and were told that there was no other fix and it's just the way the calipers are designed.

Weird thing is, only the front one is rattling and thankfully, so far I'm not getting any howling brake rub. You may want to try the supposedly spring fix and see if it works for you. Just don't bend the spring to much because it's pretty fragile.

 

[Guest]

yes, bend the spring

It's not a fragile as you might think. I just held the "prongs" with my thumb and index finger on each hand, and opened it up by sort of pinching my fingers together. Worked like a champ. Good luck!