Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  

Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Thread Tools Search this Thread
Old 11-09-10, 05:02 AM   #1
Thread Starter
Join Date: Nov 2010
Posts: 1
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
How do i adjust the brake pads on a hydraulic disc brakes for my bike?


I have a Merida S-Presso 700-D which has Shimano M486 Disc 160/160 mm.

Have had it for about 4 months.. all of sudden, I heard a noise this morning from the front wheel. It was still spinning well but I thought I could take the wheel off and clean to fix it.

Then, when I put the front wheel back, oh my god.. it became worse.

it doesn't freewheel any more..

I checked youtube.. and google it but stil couldn't find how to fix it.

Any advice?
taekr is offline   Reply With Quote
Old 11-09-10, 05:52 AM   #2
Senior Member
Join Date: Sep 2004
Location: boston, ma
Posts: 2,869
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
remove wheel, push the pistons back in the caliper, install wheel. pump lever. recenter caliper over disc. also rule out worn/loose hub. check rotor true
reptilezs is offline   Reply With Quote
Old 11-09-10, 12:02 PM   #3
Senior Member
Thetank's Avatar
Join Date: Apr 2008
Posts: 1,031
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Not sure if the shimano disc caliper has an adjustment screw but some do and it's right by the bleeding valve where you can move the pad in/out. My hayes surely don't but had the same issue when transporting the bike in the back of a friend's pickup. When I got home the wheel wouldn't go back in cause the lever got squeezed without the wheel being mounted so I just took a flathead and wedged it between the pads and pressed till the clearance came back.
Thetank is offline   Reply With Quote
Old 11-09-10, 03:54 PM   #4
Senior Member
BCRider's Avatar
Join Date: Mar 2008
Location: The 'Wack, BC, Canada
Bikes: Norco (2), Miyata, Canondale, Soma, Redline
Posts: 5,456
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
When you installed the wheel you may not have totally seated it in the dropouts. Or as you levered the QR closed you may have shifted the axle away from being seated.

While the bike is on two wheels try unlocking the lever and relocking it taking care to not lift the bike up at all. This should at least bring the situation back to where the wheel is only rubbing a pad lightly.

The issue seems to be that the pistons are not retracting. Bicycle hydro calipers seem to like using very weak return springs so it takes very little dirt and grunge around the edges of the pistons to mess things up. Remove the wheel and pads and try a good shot of brake cleaner in around the piston joints. Wear safety glasses since there will be a lot of energetic backsplash and the stuff stings like heck. Put the pads back in and with something plastic or wood push the pistons back into the calipers. Put a piece of plastic, metal or wood that is about the same thickness as the rotor between the pads and work the lever. Remove the packing and push the pads back again. Repeat until the pads retract a little on their own. Re-hose them with the brake cleaner if they are stubborn. Also check that your return spring hasn't gone missing or cracked or flattened out.
BCRider is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

All times are GMT -6. The time now is 10:54 PM.

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites.
  • Ask a Question
    get answers from real people!
Click to start entering your question.