> Now I've got a question. > > I've noticed a tendency for the '91 to develop what I'll call soft > brakes after a few moderate-to-heavy applications. On some occasions, > I even seem to be hitting the metallic-sounding stop on the brake > pedal, if you know what I mean. Pumping kinda helps, but not as much > as one might expect from experience with other cars. > > I am somewhat suspicious that someone some time may have put DOT3 > brake fluid in instead of DOT 4, so I plan on going to the mess and > trouble to flush the system. > > Sound like anything that's happened to anyone else? > > Also, I'd kinda like to get that sales pitch from a couple weeks ago > about master cylinders w/boosters for $100; still available? Off to > check the archives! > > -Blaine

Dear Blaine,

Another thing to consider: I've heard that brake fluid is hydroscopic, meaning it absorbs moisture. Over time, the brake fluid is no longer pure, but contains water. Under severe braking, the heat causes the water to change phase, i.e. from a liquid to vapor. Result: spongy brakes. I'm not sure if this theory has been confirmed. Anyway, it is good practice to bleed/flush brake systems every few years - VW used to recommend it, and I do it whenever the fluid color starts to change from clear to brownish. I don't know if VW still recommends periodic flushes. BTW, keep the fluid OFF the paintwork!

Sincerely,

John Hung 84 GL