Disk Brake piston resetting problem

[CRiegel]

Hi everyone,

I am new to this forum and also new to biking.
I recently bought a new bike (Kona "Dr Dew") and just finished putting it together 3 days ago. Today while taking it out for the first ride I noticed some rubbing on the front disk brake. I tried to fix this by taking in and out the brake pads and then using a pad spacer to re-align them, In the middle of the process I had to push back the piston in order to get the pads back in.

My problem is that now when I push down the brake It has no power and the brake lever goes all the way back without getting tight, I am also hearing a squishing sound when I push it down. I think it is a problem with the piston after I pushed it back, however I have no idea how to adjust this. Any help anyone could offer would be very appreciated!]

Thank you!!

Criegel

[GeorgeET]

Hmm, do you see fluid leaking anywhere?? Sounds like air got into the system and you need to bleed the brakes. Check manufacturers info. Also make sure the piston seal is in place and the piston is not cocked.

IMO cable brakes work for me.

[CRiegel]

(08-22-2011, 01:26 PM)GeorgeET Wrote:  Hmm, do you see fluid leaking anywhere?? Sounds like air got into the system and you need to bleed the brakes. Check manufacturers info. Also make sure the piston seal is in place and the piston is not cocked.

IMO cable brakes work for me.

Thanks for the advice!

Is it that easy to get air into the system?, like I said I just bought the bike brand new 3 days ago.

Also im not quite sure what the piston seal is or what it looks like?

I dont see any fluid leaking, as far as I can tell.

[bobtravers]

Did you use the right tool to get the piston back, or did you use a screwdriver??

[GeorgeET]

I believe your bike uses Shimano components. Check their site for info, and Parker tool site. Google.

If you got it from a dealer take it back to him.

[CRiegel]

(08-22-2011, 09:19 PM)bobtravers Wrote:  Did you use the right tool to get the piston back, or did you use a screwdriver??

I used a flat head screwdriver

[bobtravers]

Maybe you ripped a bit of the seal near piston, did you tried to spread it back while your pads were in there or did you push the piston back with the end of the screwdriver??

[CRiegel]

(08-25-2011, 06:50 PM)bobtravers Wrote:  Maybe you ripped a bit of the seal near piston, did you tried to spread it back while your pads were in there or did you push the piston back with the end of the screwdriver??

The pads were out, I pushed it back in with the side of the screwdriver, leveraging it against the caliper.