on the way into work this morning when i squeezed the rear brake lever there was no resistance and the brake didn't engage. i pumped the lever a few times and it started working again. later on the same thing happened again. any ideas on what the problem could be? if it's simply low brake fluid wouldn't the symptoms be different, eg., slowly lose pressure and not a complete loss of pressure one minute and then back to normal the next.
lastly, are the braking systems completely independent? i can get by until i get it in the shop with one intermittent brake but not two.