Another noisy disk brake problem

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DWM

Well-Known Member
Hi All

i experienced a slightly strange issue today. I haven’t been out on my bike for the last month, but managed to cycle to work this morning.

Last time I used it, the brakes were quiet and effective. Today, the front brake sounded like a fog horn! I tried some hard braking to try and get some heat into it, but it didn’t help. The rear brake was fine.

The disk looked OK, and I can’t think how it might have become contaminated whilst in the shed.

The brakes are shimono R7000 hydraulics.

Any suggestions as to what might have caused this, and how I might fix the issue (other than changing the pads and disk).

Cheers

Dave
 

twentysix by twentyfive

Clinging on tightly
Location
Over the Hill
Bit of damp or rust?
 

Slick

Guru
One of mine is the exact same but there is a faint but definite trail of grease from my headset all the way down the fork to the disk. I'm not suggesting your bike is the same but we all know a single tear from an heavenly angel is enough to set them off.
 
OP
OP
D

DWM

Well-Known Member
Bit of damp or rust?
Could be, but I would have thought some heavy braking would have helped, which unfortunately it didn’t.

One of mine is the exact same but there is a faint but definite trail of grease from my headset all the way down the fork to the disk. I'm not suggesting your bike is the same but we all know a single tear from an heavenly angel is enough to set them off.
Interesting. I will check this out and report back.

Cheers

Dave
 

I like Skol

A Minging Manc...
Had to replace a shimano caliper a couple of years ago (M785 XT) because it started to weep brake fluid ever so slightly and was contaminating the pads. It was so minor a leak that I changed the pads twice before I finally realised what was happening. The feel at the lever never suffered and the fluid level didn't drop enough to cause problems. I guess a tiny amount of mineral oil fluid goes a long way. The braking power was reduced, but worst thing was the noise when damp!
 
I checked my disk brakes last week and the mounts were lose. I tightened up the bolts and the juddering stopped.
The whole mounting system seems overly complicated.
 

Levo-Lon

Guru
Don't use your brakes ? :laugh:

Try some brake cleaner

My son in law uses that theory..
It always guarantees you dont crash at the hazard... You crash safely further along :laugh:
 

glasgowcyclist

Charming but somewhat feckless
Location
Scotland
My experience echoes that of @I like Skol . Sudden onset of noise, no discernible loss of pressure, and replacing pads and discs as a set gave me quiet braking for only about a week. It turned out the calipers were leaking a tiny amount, enough to contaminate the braking surfaces and cause the problem. A new set of calipers sorted it.
 
OP
OP
D

DWM

Well-Known Member
Thanks for all the suggestions. The brakes were new in June so I would hope there isn’t a leak. I will try and take a good look at the weekend and will report back.

Cheers

Dave
 

Heltor Chasca

Out-riding the Black Dog
Plus 1 for corrosion while unused and latterly damp.

My brakes can be silent for the first 2/3rds of my school run, then when I head into a slight uphill drag in a valley (especially in fog like today) the bike and myself become damp. On braking, at the point where I exit the valley onto a road, the front brakes shriek like murder. The rear (sheltered by panniers) remain silent.
 

Globalti

Legendary Member
If the brake judders and sqwawks as the bike rolls to a stop it is most likely contaminated with oil or brake fluid.
 

wonderloaf

Veteran
If the brake judders and sqwawks as the bike rolls to a stop it is most likely contaminated with oil or brake fluid.
I recently fitted brand new rear pads and meticulously cleaned the disc and caliper. Checked for any leaks, none found. Went out for a ride and all was quiet until it started to rain when I got the dreaded squeal, so have concluded it's not always down to contamination, just a bit of damp can cause it. Guess I'll just have to live with it!
 
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