[net.cycle] Stuck front brake

car377@drutx.UUCP (RogersCA) (10/22/86)

> Speaking of brakes, my front brake on my Honda CB550F is
> stuck.  ....
> If the problem is where I think it might be, can 
> the brake be dissasembled to that point, cleaned and reassembled?  
> How difficult is it to do? Or does the brake need to be replaced?
> Any help would be greatly appreciated.
> 
> -John Carey

Is the brake operated from the handlebar lever,
or from the brake pedal?  Is there a proportioning valve in the
brake line? (My Yamaha has dual discs on the front wheel, with one
operated by the pedal through a proportioning valve, and the other by 
the handlebar lever).  Is the brake continuously stuck? 
Is it stuck hard enough that the bike won't move, or does it just drag?  
If the brake is stuck hard, just getting the caliper off the rotor should 
be fun.

You can find out if the piston is stuck by "bleeding" the hydraulic
fluid for a second or two (assuming your brakes are hydraulic).
Make sure the fluid reservoir is full, then crack open the bleeder
nipple on the caliper until fluid comes out (this is messy unless
you put a tube over the nipple to catch the fluid.  Releasing a 
small amount of fluid will relieve any hydraulic pressure on the
piston.  If the brakes are still stuck, then mechanical interference
is probably the problem.  This might be due to any number of causes, 
e.g., contamination due to failed seals, corrosion, or jammed O-rings. 

(If you try this procedure, be careful not to get any fluid on the
rotor or pad faces, keep enough fluid in the reservoir so that no air
is pulled into the line, and be sure to top off the reservoir before
replacing the cover.)

If you don't have a fair mechanical background, attempting to repair 
this could be a risky business.  At some point in the rebuild, you
have to decide whether the cylinder needs honing and whether or not
the amount of wear present is sufficient to warrant replacement
of the caliper. If your repair fails on the road, you lose 70% of your 
stopping power.  I watched my neighbor try to rebuild his own front 
wheel brake caliper.  The piston was stuck, and he figured he could 
free it by banging on it with a ball peen hammer. He didn't free the 
piston, but he did turn the caliper into an interesting metallic 
object d'art with absolutely no circular shapes.

Sounds like this might be one for a reputable shop to fix.

Chuck Rogers @ ATT-ISL, Denver