1998 Lexus GS 300

Brakes problem
1998 Lexus GS 300 6 cyl Two Wheel Drive Automatic 134000 miles

Hi, I'm having some strange problems with my master cylinder.
My brakes work just fine, no problems at all, but the master cylinder will occasionally make high-pitched squeaky noises in rapid succession. Like squeak squeak squeak squeeeeeeek!

It's very strange, and although the brakes work properly, I don't want it to be symptomatic of further problems. Any suggestions would help! Thanks!
February 5, 2010.

Maybe your hearing air leakage from the, booster, vac supply line, either from a bad line or aged connection at the booster housing or fitting at engine.
Have someone apply the brakes continuously with the engine off and on while you listen and check under the hood. Move vac line around if you have to, to aid in finding/manipulating the noise to locate it.

Oct 21, 2010.