Brake Fluid in Power Brake Booster

[Tom Thompson]

My '84 El Camino suddenly began to 'lose' brake fluid - No leaks at wheel cylinders or anywhere else that I can find. After talking to a couple of more enlightened mechs - the concensus is that the master cylinder is leaking back into the power brake booster!!
Is this possible????
Is this a common problem??
Can I get the fluid out of the booster??
Should I replace the booster??
Thanks Much for Help....
Tom..........

[a1supersport]

Yup it's possible. Have they actually checked to see if it was leaking into the booster? The first thing I'd change is the master cylinder. You can rebuild it if you want, but I've done that...and it's only a waste of time. Besides, a complete master cylinder, after you turn in the old one, doesn't cost much. There's a rubber boot on the inside of the booster that you might want to check. Once the brake fluid touched that, it may have swelled up. But even a new booster doesn't cost much...so you might consider replacing that too. And last but not least , have your parts supplier (if they're willing) check and see if the '84 Olds Cutlass, Buick Regal, or Pontiac Grand Prix uses the same part (booster and master cyl.)...and if so, is it cheaper than the replacement for your ElCamino. Sometimes the name "Chevrolet" automatically increases the price for parts...even though the same part might be used on another GM product.

[Tom Thompson]

Thanks much for the reply. It documents that it CAN happen and I just needed to know before I got too far into the repair and find out there is NO repair.