Front brake locking up

I removed both wheels to replace the tyres....new tyres in...nice.
On my first run the bike started to slow down to a sudden stop.
Hummmm. the front brake lever was hard and the front wheel locked...WTF???
waited a few minutes and the lever became normal again and wheel unlocked.
Rode the bike home using only the rear brake.
Dismounted the front wheel....nothing wrong
Bled the front brakes.....looking good.
Went for a quick ride in my complex, some hard front braking and sure as shit the lever got hard again and wheel locked.
Anyone had this problem? Did I fooked this thing up somehow? Any ideas?
Thanks
Weber

Front calipers need rings clean or replaced? There are a couple of topics about loocking calipers use the search.

I saw those threads but just by removing and putting the wheel back on would damage the rings?

I suppose not...but did you had to force the pistons in for the wheel get back in? How did you do it? Do you ride in salty roads?

One thing I believe ( warning:not a mechanic) is clear the piston are locking up and not going back after pressure is aplied.

Could be a number of things that I don't know about though

Check you've not twised a caliper when you had it off. Brake lines should be nice and straight with no twists.

Sounds to me like this is the problem.

Nope....not twisted.
That was the first thing I checked.
Seems to be the right side caliper that is locking up.
Frustrating......any more ideas before I take the caliper apart?
I would rather avoid that route if I can, but....

By the way, bike has 6k miles and no salty roads here (Florida).

I had a similar problem with my front end, it ended up being a bent front rotor. It wasn't bent a whole lot but enough under aggressive braking that the front brake would lock up.

This has been reported before. I put it down to the brake master cylinder not working properly.
The only way to avoid it is to bleed properly at least every year or more if you do track days.
Get rid of the old brake fluid by pushing the pistons back also.

I can see how I can replace the fluid inside the lines by bleeding but how do I flush the fluid inside the calipers?

Push the pistons all the way in to get rid of the old fluid.
I push the pads appart (make sure you don't have much fluid in the reservoir).
Then I keep them appart by lodging some clean wood wedge between the disk on both sides. Then open the bleeder and flush trough.
After that close the bleeder and fill the reservoir, remove the wood and pump the pads - pistons back out while keeping the reservoir topped up.
Then bleed properly to remove air. Do both sides...

Hi mate,
I had a similar issue when I replaced the leavers, the little rod going into the master cylinder from the leaver was slighly off and locked the wheel..

do you use cheap levers? heard some people say they lock up and can cause problems.

since this happened after tyre swap, i'd say most likely bent rotor. it is easy to damage them when taking the tyre off if you're not carefull (i guess depending on the machine you use...) warped rotor would potentially overheat the caliper, causing the fluid to expand and lock up. it's also possible to damage the pads when installing the wheel... check that the wheel spins easily without brakes dragging at any point...

Bent a disc, shitty caliper pistons, or both

I think the bike is Ok now, but have to take the bike to a longer ride to prove it.
Seems that the problem was isolated to something in the brake fluid that was delaying the return of the pistons.
I pushed the piston back a couple times and flushed the fluid out of the caliper and seems to be OK now.
Let's see....

Sounds sketchy. Think you need to flush the whole system with fresh fluid again.

I force the pistons back into the calipers each time I remove the wheels which allows the calipers to be removed and installed much easier. It also forces any air in the system which collects at the higest point in the system back into the resivoir.

Whatever you dislodged by doing this is still in your lines...you need to get it outta there or it could be a disaster in the making.

John