Hi folks,

I will post this in the Diesel Discussion section also, but here is the story. My wife's 2012 ML350 Bluetec has been having some sporadic brake issues, and today it turned on the brake warning light. I put on my Xentry reader and it came up with the code for a bad brake vacuum pressure sensor. The problem is this, the sensor is on the bottom face of the brake booster, under the master cylinder. I have fairly long fingers, but it is almost impossible to get to the sensor with the master cylinder bolted to the brake booster.

My question is this.....if I unbolt the master cylinder from the booster without opening any brake lines, it should not require bleeding the brakes, correct? It has been many years since I have had to replace a master cylinder but if I remember correctly, as long as the brake lines are not opened or removed, it should be a simple unbolt, then bolt back up procedure.

Many thanks

__________________
2012 Mercedes ML350 Bluetec 102K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 238K (mine)
1998 Volvo S70 T5 Turbo 211K (kids)
1994 Ford F150 4WD 246K (firewood hauler)
1983 Mercedes 300D 384K (diesel commuter)

Parts of Master Cylinders:
#1. Lever or Pedal.
#2. Piston.
#3. Spring Return.
#4. Pushrod.
#5. Bore.
#6. Piston Assembly.
#7. Reservoir.
#8. Brake Fluid.