What the hell just happened to my master cylinder?

[Rowroy]

I just replaced the master cylinder on my '69 Beetle. After successfully bench bleeding and installing it, I started to bleed the wheel cylinders. My helper was pumping the pedal while I was manning the bleeders. I could get nothing out of either of the rear wheel cylinders. I tried the front ones, and they bled fine. After doing both front wheels, I headed to the rear of the car to give the back brakes another try while my helper started to pump up the pedal again when WHAM-O! His legs got sprayed with brake fluid. I think the front seal of the master cylinder blew. I'm thinking this unit was defective.

One side note: Just as we were about to start bleeding the wheel cylinders, my helper sat in the drivers seat, pressed the brake pedal down, and a rather large puff of air shot up from the master cylinder. At the time, I attributed this to air being trapped behind the rubber boot. I'm starting to think there may be more to this, though.

Did I screw up somehow?

[Matt Wilson]

sounds defective, return it, sounds like you know what you are doing.
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1972 Standard Beetle
1969 Baja Beetle

[propflux01]

Sure it wasn't the hardline that goes right by the accelerator pedal? I mean, 1st no fluid to the back, and wham, fluid everywhere? These things love to rust right in that area..

[Rowroy]

I never thought about the brake line near the gas pedal. It's in the hands of the local VW guru now. I figured that I better quit before I did something that I would have regretted . . . like beating the car to an oily pulp with a bat.