Brake Issues after a bike shop tuneup

[zriri]

I am some what new to all this so bare with me and feel free to ask any questions.

I have a Specialized Rockhopper comp 29. I have had it for 4 years now and have never heard the hydraulic disc brakes squeal. They have also always been very grippy, if that is the right word. I could squeeze the brakes and have the ability to completely stop the tire from spinning with very little effort. Today I took it in to the shop for a tune up. Now that i have it back the brakes squeal and i can barely squeeze hard enough to completely stop the tire from spinning. Is this something on the brake rotors or pads that will evaporate off with time or ware off with use after a while or is this something else? Below is a list of everything that they did. Could there have been some over spray form something used in one of these processes that may have gotten on the brakes?

• Inspect Bicycle Frame
• Tighten Chair Rings & Cranks
• Tighten all Bolts & Nuts
• Wheels Trued & Tension
• Hubs Adjusted and Checked
• Check Derailleur Hanger
• Check/Adjust Brakes
• Check/Adjust Gears/Derailleur
• Check/Adjust Cables for Wear
• Lubricate Chain
• Degrease and Wash Bicycle
• Adjust Tires to Recommended PSI
• Lubricate the Derailleur

***If the bike shop is reading this, Sorry! I really like your store/service and will be back. This one thing is not a big deal and i want to make sure i am not missing something before i just bring the bike back.

 

[CAMPYBOB]

Maybe clean the rotors and brake pads with denatured alcohol? Oil, grease film or wax can cause a brake to squeal and change the coefficient of friction.

Maybe take it back to the shop with the brakes still squealing and let them clean it and further diagnose the issue?

 

[oldbobcat]

Every so often a good shop lets a bike out with squealing brakes, so the first thing to do is take it back and ask them to fix it. The first thing I check is that the caliper is centered over the rotor and both pads squeeze in to hit the rotor. Sometimes there's a sticky piston that needs freeing. After that, it's checking that all the mounting bolts are tight and that the pads and rotors are clean. If that fails, sometimes it's just time for a new set of pads.