Howdy! I had an issue pop up back in October where my e brake light came on and would randomly turn off, but after a few weeks of this the light stays on constantly. If I leave the truck off for a while, or turn the engine off and pump the brake pedal, the fluid returns to the reservoir and will eventually reach the MAX line.
When the pump on the master cylinder turns on, it takes several attempts to fully prime the brake system and sucks down half the fluid. The fluid level always returns to the MAX line if the truck is off long enough so it doesn't appear that I'm losing fluid.
I'm providing links to the videos I took of the problem in action at the bottom of this post.
I dug through the forums here and found out that the brake light is indicating that the pads are too low and need changed. I recently replaced the front pads, however upon checking the rear pads it was clear they need to go.
Today I installed the new rear pads expecting the fluid level to be back to normal when I turned the truck on, but the same problem still persists.
I bled the brakes all around to make sure there wasn't any air or old fluid in the lines so there's now fresh fluid in all 4 calipers. While doing the bleed I checked for wet spots on the calipers and found none.
At this point I'm not sure what the issue could be and hoping someone here might be able to point me in the right direction. I'm guessing I may need to have a full system flush to ensure there isn't any air in the system.
Thanks in advance! Video links below:
Video of master cylinder pulling the fluid from the MAX line:
Shared album - Cody Stokes - Google Photos
Video of fluid being pushed back into the reservoir when engine is off:
Shared album - Cody Stokes - Google Photos