iliescu_l,
You may have screwed the piston in too far, it only needs to go far enough to get the pads to slide over the rotor.

To adjust the piston outward, to allow the rear brakes to be effective, you need to operate the parking brake repeatedly. It usually works best if you do around 10 parking brake applications then apply the regular brake, then repeat.

If that does fix it you may need to remove the caliper and manually turn the piston back out until the pads just slide over the rotor, then perform the repeated parking brake application.

George

 

WOW , I did not know that you can go too far with the piston. I screwed till it stopped.That will make sense.
However the new caliper I bought, I checked the piston it is all the way in.
I did not replaced it yet because I saw the piston moving on the old one .I will try to bleed that line first to see if it helps.
I will post results.

"you may need to remove the caliper and manually turn the piston back out until the pads just slide over the rotor, then perform the repeated parking brake application" ..... when the pads get thinner , how does the piston adjust to get out ?

 

It has to be something else becasuse I did the same thing on the right back side and that one works just fine. I screwed piston all the way in without forcing it and it still works fine.

 

Since the piston is moving I suspect the piston just hasn't adjusted itself properly yet. Did you try actuating the parking brake repeatedly? It can take many, many actuations to adjust the piston.

If you didn't open the hydraulic lines, bleeding the line isn't likely to help.

They adjust automatically.

It should be fine to turn it all the way in, but sometimes it will stick and not adjust properly. I would try to backing the piston out some before replacing the caliper.

George

 

Hi Geroge , thank you for your answers.

"Since the piston is moving I suspect the piston just hasn't adjusted itself properly yet. Did you try actuating the parking brake repeatedly? It can take many, many actuations to adjust the piston."

I did try multiple times (30 times at least) and it had no effect.

"It should be fine to turn it all the way in, but sometimes it will stick and not adjust properly. I would try to backing the piston out some before replacing the caliper.
"

What would be your sugestion on how to et the piston out more? I was thinking to install everithing without pads and see how muxh the piston comes out.Not sure, I never tried.Does it stop to a point or it comes all the way out if nothing stops it?

 

Remove the caliper and turn the piston counter-clockwise to back the piston out. Back it out until the caliper just slides over brake pads without excess clearance.

Don't trying that, the piston might pop out of the caliper.

George