front brakes locked on tight

[bruce_launceston]

Hot here today. I was riding home from work and I noticed that there was almost no freeplay on my front brake lever.
I got to about 500 metres from home and I had to pull over as the free play had all dissapeared and the front brake had locked on tight. I tried to slowly ride onto the footpath but when I got onto the grass the front wheel locked and the back tyre just spun in the dirt.
I walked home and got a 11mm spanner and some tubing and went back and released the bleed nipples on both calipers.
This freed up the brakes and I was able to ride home.

I sucked all the fluid out of the mc reservoir and removed it. The tiny hole in the bottom was blocked solid and it took me 30 or 40 minutes of digging around with a 29 guage hypodermic needle before I got it clear. The hole is tiny, the needle was 0.33 mm so I guess the hole might be only 0.35 mm diameter.

I'm guessing that it has been blocked for a long time as the lever play was varying with the weather temp last summer. Since then I had got rid of some stubborn air bubbles and got the brake lever back to normal so when I rode today in the heat the blocked return hole meant that the brakes eventually locked on, the lever was rock hard.

I'm guessing it will also be a lot easier to bleed the brakes from now on.

Cheers Bruce

[unibober]

Good to hear they didnt lock on the Interstate.  Endo is no friendo.

I remember working at a bike shop when Cannondale introduced their in house disc brakes. The fluid was supposed to be a highly engineered, space age fluid that was to be far superior to DOT fluids.  Well they quickly learned that as the the rotor/pads heated up, so did the fluid. Not usually a problem.  Well heat caused fluid expansion and so as you were bombing down a hill your brakes would suddenly lock tight.  Glad they figured that one out before they started making motorcycles and ATVs.