Still on failed brakes? Usually brakes fail from improper servicing. The only time to modify the brakes is when you have exceeded the O.E. parameters, or in the case of Lincoln LS's, Turbo coupe T Birds, and Buick Grand Nationals, their 80's design electric/hydraulic brake pumps wear out. The automakers experimented with these systems not knowing how they would fare 20 years later, nor did they care. it worked for them at the time. You keep refering to brakes failing on what? Race cars? All of the examples you have given, and someone's book you referred to, concern drag race cars, not even related to G.N.'s. I would guess that 95% of G.N.'s on this site are street cars, driven by street drivers. Most real drag cars have trans brakes, and are not subject to most G.N.'s here. To realistically drive this type of high performance STREET CAR everyday, in traffic, (in California it is a chariot race to work everyday) you need immediate brake response. Just driving to work does not heat up the rotors red hot, as in a road race. The rotors are relatively cool on the freeways. (That's why there are holes in the wheels, to spin air around the rotors) IF a G.N. won't stop like you want down at the first stop sign in the morning, cold, then it has nothing to do with rotor heat. The booster is what applies the pressure to the brakes. You say that Buick did not know how to match the brakes on the G.N.? Call them, and ask why. They used the Powermaster from the factory for a reason, instead of vacuum, because they knew the liability of blowing the hose off the check valve, and that may have happened to them at the test track. They knew the vacuum limitations of a 231ci , turbocharged engine. They test this stuff before they sell it to the public. GM only looks at things as to how they will be sued for brake failures. They elected not to install a standard Regal booster and pedal in a heavy car with this potential for speed. In 1986, a vacuum booster only cost GM $15.00 from Delco. Why didn't they use it? Obviously, the Powermaster had to cost them a LOT MORE, and they still used it. The main downfall of the P/M is that it pumps brake fluid under high pressure. Brake fluid is not really a lubricant. Worse, it absorbs moisture from the air, making it corrosive to the system, and the pump. The phenolic vanes, pumping brake fluid, wear out, and the pump can't reach the 2400psi needed to open the gray pressure switch to shut off the 12v motor. That's why the hydroboost is superior. It receives it's pressure from the p/s pump. As long as the engine runs, there is pressure available. The accumulator takes over if you need high pressure stopping after the engine is off. As long as the p/s fluid is kept clean, (it is an oil) the Hydroboost will always perform.
