09-29-2013, 01:14 PM
As in the previous post about master cylinder, the brake problem isn't gone (bleeding didn't help, but of course firmed up the brakes).
The ! warning light pops on, along with the red brake warning on the right of instrument panel. It comes on randomly, just driving down the freeway, stays on for just a second, it might happen about 5 times in half and hour, never stays on for more than a second. I can't correlate it with anything like speed or driving behavior. Fluid level is fine, and with the bleed it was all inspected, no leaks. One odd thing, the light has come on a few times when I was actually braking, and the pedal looses pressure and goes down about 1/2 an inch -- yeah, this experience certainly is confirms that your body still secretes adrenalin. But then when let off the pedal, and it is all back to normal.
So there is something that is "playing" with the pressure, I almost suspect the ABS control unit, because I can't think of anything else that would adjust the pressure. The shop says that essentially always when the light is coming on, without a known problem, it is the level sensor in the reservoir or the wear sensors. I was planning to "short" them all out to try to diagnose this thing, but then those causes wouldn't create the condition mentioned above where the pedal slips down when the light comes one. The shop simply recommends to replace the master cylinder, but there is no evidence that is that problem (only experienced guess work). I can't think of a caliper condition that might cause this.
So very odd, why does the light come on randomly while not eve braking, why would the pedal "loose pressure" when combination of braking and the light comes on.
Any ideas or suggestions would be much appreciated. Thank you.
Roland
The ! warning light pops on, along with the red brake warning on the right of instrument panel. It comes on randomly, just driving down the freeway, stays on for just a second, it might happen about 5 times in half and hour, never stays on for more than a second. I can't correlate it with anything like speed or driving behavior. Fluid level is fine, and with the bleed it was all inspected, no leaks. One odd thing, the light has come on a few times when I was actually braking, and the pedal looses pressure and goes down about 1/2 an inch -- yeah, this experience certainly is confirms that your body still secretes adrenalin. But then when let off the pedal, and it is all back to normal.
So there is something that is "playing" with the pressure, I almost suspect the ABS control unit, because I can't think of anything else that would adjust the pressure. The shop says that essentially always when the light is coming on, without a known problem, it is the level sensor in the reservoir or the wear sensors. I was planning to "short" them all out to try to diagnose this thing, but then those causes wouldn't create the condition mentioned above where the pedal slips down when the light comes one. The shop simply recommends to replace the master cylinder, but there is no evidence that is that problem (only experienced guess work). I can't think of a caliper condition that might cause this.
So very odd, why does the light come on randomly while not eve braking, why would the pedal "loose pressure" when combination of braking and the light comes on.
Any ideas or suggestions would be much appreciated. Thank you.
Roland
