Bicycle pads squealing

Shimano brake pads started to squeal like crazy on my mountain bike. Hydraulic system with disk brakes. So I did the usual: parts cleaner to the pads and rotor. Then scuffed the pads with a file, and cleaned with brake parts cleaner again for good measure. Scotch brite pad to the rotor and more cleaning. Made sure caliper is centered to the disk. Disk is not warped.

Anyways, didn't make any difference. Still loud as hell. Annoying loud.

Any idea on what to do next? Buy a new set of pads?

 

With rubber pads, it's usually the toe and/or dirty rim.
Never had to deal with a disc doing that.
Try using sand paper on the pads and rubbing alcohol on the disc

 

Your pads are either very thin or contaminated. New pads, clean the rotors and bed the new pads in. Happens a lot with mountain bikes.

And stop dragging the brakes while riding.

 

It could be the piston to pad interface, as the coating (if any) on the pad has worn, or there is a contaminate on the back of the pads/surface of the piston (or actuator, I don't know bicycle hydraulic brakes that well).

With my mechanical disc brakes I adjust the arm travel to zero (and center the pad, as you have), cable slack to "a little," and clean everything like you did, which usually cures the squealing.

 

think the replacement pads on my shimano hydraulic were $18 set??? Definitely stopped the squeal

 

I guess I am more annoyed that I can't figure out why they wont stop. Still lots of life left in the pads.

 

Loud Pads Save Lives.

 

Have you tried peeing on them ?

 

I piss on the whole bike after each ride.

 

You gotta pee on them while riding.


(personal admission: I've peed on a rattle snake. It didn't stop rattling.)

 

Sorry man, doc says your gonna die.......

 

Loosen the brake caliper from the frame (do not remove, just loosen), squeeze the brake lever and tighten the brake caliper while squeezing. This is a centering issue and is easily resolved.

 

Done that already.

 

Hmm, it sounds like you tried just about everything except the pads. You may have hit some impurity in the pad compound and simply need to replace them. Sorry man.

 

You could try not using them so much, think of that squeal as a training tool .

 

I just did the same on my Ultegra discs and pads. scuffing the pads with sandpaper helped the most. but the squeal is still there at lesser brake pressures. theres also a distinct lack of bite and stopping power. so I'd bet they are contaminated. im just going to buy new pads now.

 

I've heard a light pass with a blow torch across the pads may help burn off any contamination. Worth a try.

 

I switched to EBC pads on my older mtb which had a Hayes system. No more issues.

Pads are cheap, just try new ones.

 

Pad contamination happens all the time with mtn bikes. The other easy way to get the squeal, or turkey gobble, is not bedding them in right and/or riding the brake too much.
Just really easy to swap pads and do a handful of hard stops up and down the road before heading out. You can sometimes get contamination to loosen up and pads work better on metallic pads by doing the wrong thing and riding the brakes getting them really hot, but then you have to eventually fix it right anyway and now probably bleed them. Organic pads (which are way better than metallic anyway) are screwed once contaminated. Sanding/filing/cleaning them won't do anything but contaminate them worse.