AO Platinum Member
Join Date: Feb 2002
Location: The land that Time forgot
No... if air is in the system, then pumping the brakes would not make any difference.. you would have a consistently spongey pedal as the air that causes the sponginess isn't going anywhere. Sponginess gets worse with hot brakes (as the volume of air increases) but pumping the pedal won't change anything caused by air in the system.
If the pedal sags the more you press it, then the master cylinder is letting fluid past the internal O-rings. You need a rebuild or a new master cylinder to sort it.
You can bleed it first before you rush out to buy a new m/c.. just to prove it to yourself... but if you have worn o-rings or a worn inner bore, then when you press the pedal the fluid in front of the piston that is acting on the brake circuit escapes back into the reservoir with the pressure, so the pedal drops. Pumping it helps because you effectively reload the fluid volume ahead of the piston... but if you hold the pedal under pressure, it'll start to sag again.
No bullets for Chaingun..