PISTON AND VALVE OF MY CALIBER IS TO BE REPLACED, A LOCAL MECHANIC SAYS,AGE OF THE SAME IS NEARLY 9 YRS,WHAT SHOULD I DO NOW?

I HATE TO TELL YOU THIS, BUT A WHITISH LIGHT BLUE SMOKE IS NOT YOUR VALVE SEALS....IT IS YOUR PISTON RINGS. IF YOU REV YOUR ENGINE, AND MAKES MORE SMOKE, IT IS DEFINITELY YOUR RINGS.

I wonder if they really replaced it or just cleaned it up & put it back on. A good rebuilt caliper shouldn't stick that soon. They DO, eventually, because the piston is often made of a plastic that gradually swells over time... but a good rebuilt should have a new piston in it. See if the honor a warranty on it - if not, try a different supplier of rebuilt calipers.

Hard to say. Any scratches/blemishes on the surface of a piston can cause heat concentration, leading to premature failure. I would suggest taking a close-up photograph of that piston, along with another one for comparison, and show them to a local mechanic that you trust. I'm assuming that you are taking care of the head/valve issue that caused the damage, as there is probably some valve damage to repair as well.

look at your front brakes you have a brake caliber, on it you will see a piston that pushes your brake pads in when you apply your brakes sounds like your piston on brake caliber is sticking.they have rebuild kits at your local parts place hope this was useful.

Caliper piston is sticking. Try pushing it all the way back to the bottom of its travel and then pump the brake pedal slowly and lightly until the piston has reached a point of contact with the pads.

I've not had much success with this method. Usually, if a piston sticks, you're better off to just replace the caliper.

To remove the front disc brakes , you must remove the break caliber assembly . Keep in mind that on some brake calipers a special Torx Drive T40 or T45 must be used to remove the caliber bolts from the spindle assembly . Also , Allen (Hex) bolts are sometimes used . Be sure you have the right tools .
1. Properly block both rear wheels at the front in the back of each wheel.
2. Loosen the lug nuts on both front wheels one turn on each nut.
3.Jack up and support the front of the car on Jack stands with the wheels one to 2in. off the ground.
4. Remove the two bolts on the inside of the caliber the secure it to the spindle .
5.Once the bolts have been removed the caliber should pull straight away from the rotor and spindle assembly .
6.Remove your old brake pads , clean the assembly , properly lubricate the moving parts as necessary , especially the floating sleeve as the assembly is called a floating caliber which means half of the Caliper is bolted to the spindle (inner) but the other half floats (outer).
7.Use a large see clamp centered between the caliper piston and caliper housing to push the piston all the way back into the caliber cylinder by turing (1 turn at a time) the screw until the piston is flush with the caliber face .
8. Install your new brake pads .
9. use the reverse procedure to assemble everything back together. Good luck and be safe....

may be bad caliper could be why pad went to metal/metal

Sounds like you accurately diagnosed the problem. You didn't mention aany grinding noise so it sounds like a sticking caliper, Remove wheel, spray piston with disc brake cleaner.

Also inspect pads for wear and rotor for scratches, grooves. If pads thin, or rotors damaged, find a mechanic.

If cleaner doesn't free the piston, you should, again, get mechanic to check it out.