Brake caliper issues

[Beer van Huet]

On Facebook, I read a lot of articles lately from people who are having trouble with their brake calipers/pistons.
I am just wondering, is this becoming a widespread issue (like we had with the leaking carbs and fuel petcock) or due to bad maintenance.
My approach is, besides regular- to do preventive maintenance and if anything pops up with a lot of Valkyries, I'd rather fix it before it becomes problematic.
This worked very well for me since I bought my new Valk in 2000.
I can imagine that if you don't renew the brake fluid, a problem like this will occur.

[Dusty]

I recently had front brakes that would not release. Stripped down master cylinder and  brake calipers. Cleaned master cylinder but could not find any problems. Brake caliper pistons had dirt build up on exposed part of the pistons but no scoring in the bores. Cleaned everything and it is operating properly again. What caused it. I could not find anything obvious but my first guess would be dirt in the system or stuck pistons.   140,000Kms.

Dusty

[old2soon]

     Years back my rear brake caliper on my 99 I/S locked up. When I got it torn down the exposed area of the piston turned out to be the culprit. NO damage to the piston bores but rebuilding the caliper-replacing the O rings and cleaning the pistons and fresh brake fluid and working like new again. And right at that point decided to clean and rebuild both front calipers. The front calipers weren't as crudded up as the rear calipers were but the were gittin close. RIDE SAFE.

[indybobm]

When rebuilding the calipers, make sure that you have cleaned the groves for the piston o-rings. Gunk can accumulate there and keep the pistons from moving freely in the bores. Just cleaning the exposed end of the pistons and slapping  new o-rings on is not enough.

[HayHauler]

I just had this happen to me on the front brake master cylinder.  The brakes would lock up and get progressively tighter the further I rode.  I had to stop on the side of the road and crack the bleeder valve open to relieve the pressure so I could continue the ride home.  I replaced both front brake and clutch master cylinders and back in business.
The issue, I found out after replacing them, was that the TINY hole that is under the stainless little clip, was rusted shut.  This would not allow the pressure from the brake system to release.  I had originally bought the OEM rebuild kit and will rebuild the original units and keep them as spares.

I hope this helps someone,
Hay 
Jimmyt

[Jess from VA]

My front brakes have been getting grabby, sticky, jerky (they still stop you, but NOT smoothly).

I had a big full service with all new fluids and pads last year.

In the past, I got good results from scrubbing the daylights out of the front brake calipers (no disassembly) with mildly corrosive S100 (or Spray 9) with a collection of stiff bottle brushes, and water flushing, then blowing dry with the Stihl blower.

But today, though they were only mildly dirty, the scrubbing got me no improvement at all on test ride.

So I pulled the hand lever pivot pin, removed the lever, and discovered that they really greased everything up in there, but the grease had completely dried out, causing only friction.  So I cleaned all that off and regreased with fresh goop, and my 2d test ride was back to fully smooth braking.

Some days, I get lucky.   

[Hook#3287]

Replacing the brake fluid every 3 years or so will prevent some issues but not all.

The Pistons need inspection and possible removal and cleaniing at times.  While your there, new seals and complete cleaning of all the interior of the caliper should happen.  Maybe every time you change out pads (extreme) or when something doesn't feel right.  Some riders get away with just cleaning the pistons while still in the calipers.

The master cylinder should be inspected and cleaned periodically.  Of course, every time you swap fluid.

I feel it has a lot to do with riding frequency, conditions & preventative maintenance and every bike and rider will experience different outcomes.