Disc brake issues HELP

sheepshifter

Hi new pads, new roters, and bled by my LBS and still no power in the rear and squeals.Model of brakes are 2009 shimano came has standard on my Genesis SS, is it possible a brake can just loose the ability to give you power and are beyond repair.Could do with not throwing more money on them if there fit for the bin

Paulkingk

Does the brake feel spongy when you pull the lever? have you checked that both the pistons are moving in and out when you pull the lever

sheepshifter

Each piston moving in equal amounts and no spongey feel

The Rookie

Squeal and loss of power not necesarily related, many brakes squeal when working very well!
Shimano what?
As Paul asks, is the lever coming back to the bars or is it it nice and firm. If its coming back to the bars then it needs bleeding, if its not the pad/disc interface is not generating enough friction which is usually caused by contamination with oil/grease.

No brakes can't loose power, the force you apply at the lever has to be countered by the pads squeezing the disc (without going through the chain of interim opposing forces) without a specific (and fixable) fault.

Simon

cooldad

Sounds like you have a rubbish LBS if they gave the bike back not braking properly.
Easy enough DIY job, pads and rotors are 5 minute jobs, and Shimano bleeding is easy, and not too messy as the fluid is quite pleasant compared to DOT fluid.

sheepshifter

Thanks for your replies LBS said the pads im using are known to be hard and not biting has they should pads are Superstar.The model of the brake is M486 roters are also Superstar,i use these in my Avids and V2 Hopes on my other bikes and no issues.

Paulkingk

New Pads will need time to bed in, and pads that aren't bedded in would def cause a lack of power when braking. give it some time maybe 3 to 4 ride with plenty of hard braking if it doesn't improve maybe you LBS got some hydraulic fluid on the pads/ rotor in which case try de-greasing the rotor with a quality de-greaser like muck off and soak the pads in de-greaser as well, reomove the pads from the de-greaser and rub them down a bit with sand paper. refit and give it another few rides, if they don't work after that take the brake off your bike and throw it in the bin.

cooldad

Nothing wrong with Superstar stuff - works fine.

ricardo_smooth

cooldad wrote:

Nothing wrong with Superstar stuff - works fine.

agreed, however if they are sintered pads they need some heat in them to make them work properly (in my case with saints anyway)

cooldad

Agree but just a bit of heavy braking should sort them.