Shimano brake problem

[robsc]

I have a Giant ATX 29er with the Shimano BR505 brakes , I have a continuous problem with rear brake squeal . I have changed pads , cleaned rotors and after 1 or 2 rides the noise is back . Strangely the front dont make any noise . Whilst I understand that they are entry level surely they shouldnt squeal . 

Should I try a new rotor ? Will this help as I don't want to buy one and it doesn't help at all ?

Any help will be appreciated ?

[wepat]

How did you clean your rotors with what substance?

[robsc]

With isopropyl alcohol 

[fanievb]

sounds like an alignment issues (see the youtube link) http://www.parktool.com/blog/repair-help/shimano-hydraulic-brake-service-and-adjustment 

 

also did you bed the brakes after you cleaned them?

 

http://www.bikeradar.com/gear/article/workshop-how-to-bed-in-disc-brake-pads-31337/

 

[robsc]

Thanks Fanie . I cant open the video link at the moment . I did after cleaning and sanding them , bed them in . As soon as I went out onto a local gravel road they would start squealing again .

[Jewbacca]

You could very easily have glazed the pads... rub them with a very fine sand paper and you may come right.

[TNOSE_E]

 

As per video, try rubbing the pads together with sunlight liquid under hot water.

Brake clean the disk too.

 

Might help.

[robsc]

Have tried the sanding bit , haven't tried the sunlight part . Will give it a go , nothing to lose . Thanks 

[robsc]

Last night I cleaned pads with sunlight liquid and very warm water . I then stuck a piece of masking tape behind the pads (on the front side) to create a "toe-in" effect . I then did a few stops from 25km/h to 0km/h and had no noise . I guess time will tell . 

[TNOSE_E]

Last night I cleaned pads with sunlight liquid and very warm water . I then stuck a piece of masking tape behind the pads (on the front side) to create a "toe-in" effect . I then did a few stops from 25km/h to 0km/h and had no noise . I guess time will tell . 

Cool, let us know how it goes.

[robsc]

Seems to be working "so far so good" . Wonder if it's the sunlight or the "toe-in" 

[GAP]

Seems to be working "so far so good" . Wonder if it's the sunlight or the "toe-in" 

Maybe it's the Windhoek

[robsc]

Maybe it's the Windhoek

 

Or a combination , must remember to save my last drop for the pads 

[Bobbo_SA]

On full size pads I've seen the guys use a grease of some sort on the outside between the steel part of the pad and the piston, perhaps that's what your tape is now doing, I suspect after a few bike washes the tape might deteriorate and need to be replaced.

[cfcjim]

You could try brake lubricant (high temp. grease) to damp the vibrations between disc brake pads and caliper pistons. It's applied to the rear of the pad.

 

As mentioned above, the tape is probably doing this very same thing.

[worriesnot]

On full size pads I've seen the guys use a grease of some sort on the outside between the steel part of the pad and the piston, perhaps that's what your tape is now doing, I suspect after a few bike washes the tape might deteriorate and need to be replaced.

copperslip - but just on the outside of the pad and just a tiny amount. prevents high pitch vibration between the outer of the pad and piston.