Well, I was changing the front brake pads in a hurry last weekend and instead of mounting the caliper so that the rotor sat in between the pads, I put it back on with both pads on the same side!  Ugh!  Serves me right for doing this for the first time in a rush.

Anyway, I rode it around for about 20 - 25 min and noticed that I was getting slightly less braking power but thought that was normal since the pads have to be broken in.  Finally, I came to a light and the front brake basically stopped giving me any braking force at all.  Pulled over and kicked myself for what I'd done.  I re-mounted the caliper correctly and rode home.  But now, I don't seem to get any braking power out of the front brake at all.  I can push the handle all the way down and still roll the bike forward.

So it looks like part of the caliper (circled in the picture attached), which was rubbing against the rotor when I was braking, actually melted onto the rotor itself and is now deformed.  I'm thinking that I need to buy a new caliper assembly, bleed the system, and put the new one on.  Does that sound right?

And can I just sand off the junk that melted onto my rotor (picture in next post)?


Any and all help appreciated.  Thanks!

Here's another photo where you can see the part of the caliper that was rubbing against the rotor.

Be of good cheer,  your goof isn't as bad as you think it is.

It ain't fatal and it has been done before (me and Toymaker did it to his bike).   It required no replacement parts and only an hour of filing, etc.

Simply file the aluminium legs that melted on to the rotor until they are flat again.  It is aluminium, so it files pretty quick and easy with a large coarse flat file.  Toymaker and I ran out of patience and his weren't perfectly flat and square so it held his fixed pad slightly cocked and the face of the pad wore in that way to be true to the rotor and once worn in it worked perfectly for like 5-6 years (until next set of pads).  

Actually, it worked perfectly almost at once since we immediately went on a Dragon Run and he lived ....

He only lost the amount that it was off square from his total pad life.   Plus, next set of pads you can always file some more to get it better square if you want to.

The stuff stuck to the rotor is really stuck on there so peel off what you can with a razor blade (use a scraper holder) and lightly hand sand what the razor blade can't remove just to blend in the edges some.  

You do not have to get it all off -- what remains will wear off quickly due to natural brake pad / rotor wear.   It will be GONE in a week.

==========


dirty thought if you don't like filing


Rough up the surface of the erroded arms until JB will adhere to it well.  Mix up some can type (thick) JB Weld and apply it thickly to the aluminium arms tips that are currently eroded.   It needs to stand positive to the uneroded part of the machined surface.  

Wait a bit until the JB is starting to thicken up and get almost stiff, then lay some aluminium foil over the JB paste (to provide a release point) then put your brake pads back in place, assemble the brakes and very carefully squeeze the brakes just enough for the JB to be pushed even with the still true machined surface.   Release hand pressure and leave for 24 hours .....

24 hours takes a long time, don't it?

Take your pocket knife and trim the excess aluminium foil away.   If you want, you can file the JB ooze so everything matches up.   You now got you a custom "true to your rotor" fit again.

(hey, grab a part of the rotor that doesn't have any lumps on it, OK?)

Thanks, JOG.  You got it, the pads were together on the side of the "hockey puck".  And thanks for the reassurance - definitely felt like a dummy as soon as I figured out what had happened.

What I don't understand is why can I now push the lever all the way down and still be able to roll the bike?

Did you loosen the hose while working on the brakes?

Answer one quick question, is the piston in the caliper actually moving at the exact same whole time the lever is moving?  If the lever moves and the piston isn't moving at any point in the stroke, you got air in your system.

If so, then you need to bleed the brakes to correct your issue.  Likely you need to check again that all the pieces are in place correctly and then bleed your brakes to get full hydraulic pressure back.

Yea, I remember the day I slapped pads on a car at a friends house.I didnt pump to get a pedal, drove away, ran the first stop sign in an absolute PANIC!  Ive learned Quite a Bit in the years since.
When we press the puck in to make room for pads & rotor we hafta work the brakes till the pads press against the rotor before we have brakes again,.

denistheruski wrote on 02/15/13 at 16:39:03:


short & sweet answer?

Bleeding removes any air that gets into the system  .

Draining and refilling without bleeding can introduce air into the system   .