First Generation Firebird-L Mailing List .........................................................................
--- On Sat, 9/19/09, First Generation Firebird-L <[email protected]> wrote: From: First Generation Firebird-L <[email protected]> Subject: Firebird-L Digest XI #255 To: "First Generation Firebird-L" <[email protected]> Date: Saturday, September 19, 2009, 6:40 PM First Generation Firebird-L Mailing List ......................................................................... Firebird-L Digest XI #255 - Saturday, September 19, 2009 > Sent: September 19, 2009 2:41 PM > To: 'First Generation Firebird-L' > Subject: RE: [FGF] Brake job 101 > > First Generation Firebird-L Mailing List > ......................................................................... > Ok, I'll explain. > > It's simple physics. > > Boyles law states that pressure and volume are inversely proportional. > As volume decreases, pressure increases.... > > Take a full, open bottle of wine and flip it over to pour it out. You'll > notice that it glugs. The air is rushing in to replace the liquid > leaving the container. Remember atmospheric pressure is 14.7 psi and the > inside of the bottle wants to have the same pressure as the outside. > > Now, do the same to a 2 liter of pepsi. You'll get the same glug BUT the > container will also try to collapse. As the fluid leaves the container > it is creating a void that the atmosphere is trying to fill and it is > easier to collapse a plastic container than a glass one. The atmosphere > does not know or care that the container is there, it just wants to fill > that void. > > The same is true of buoyancy. But, we'll save that for the next science > class. > > Now let's apply this theory to brakes. > > As you apply the pedal you are forcing fluid out of the reservoir into > the line etc. there has to be atmosphere to replace the lost fluid. Yes, > there are those rubber bellows that collapse down BUT the kicker is > there has to atmosphere above them or they are working against a vacuum. > > joe You should always take the top loose and while compressing the pistons, keep an eye on the fluid as it will expand over the top of the reservoir while you compress the pistons back in. I always use a turkey baster to suck out the fluid while compressing. If you had the lid on and started compressing the piston, you would be putting a load on all the seals that were not made for back pressure. The thinner the pads get the more fluid your system needs so when you go back to new stock thickness , you will overflow if you kept up on your brake fluid maintenance. You should never have brake fluid left out in the elements for long periods. I read that in 24 hours, your brake fluid is so contaminated with moisture that you should get rid of it and buy a new bottle. The hydraulic system is a fully sealed system and should never see atmospheric conditions. Any moisture you let in will stay in the system and rust away all steel parts. Thats why the 4 piston calipers in the 1967-68s would always leak as the pucks were made of steel and the caliper is made of cast iron which both rust and take out the seal and mar the caliper bore. Thats why the aftermarket 4 pistons have stainless. Its all about the moisture. The moisture in the system will always seek the lowest part of the braking system which is the caliper. ------------------------------------------------------------------------ Submissions to Firebird-L: <[email protected]> Unsubscribe from Firebird-L: <[email protected]> Help: <http://FirstGenFirebird.org/firebird/Firebird-L.html> Classifieds: <http://FirstGenFirebird.org/ubb/> Owner Pictures: <http://FirstGenFirebird.org/show/>
