Booster Vacuum
Booster Vacuum
Couple quick questions about my brake booster (79 F350 Dual Diaghragm)
1.) When I pump up vacuum with a mity-vac directly connected to the booster, it almost immediately leaks down to nothing. Is this a sign of a bad booster?
2.) How much vacuum do I need for the booster to work properly?
Thanks!
Jeff
1.) When I pump up vacuum with a mity-vac directly connected to the booster, it almost immediately leaks down to nothing. Is this a sign of a bad booster?
2.) How much vacuum do I need for the booster to work properly?
Thanks!
Jeff
Under normal operation there is a check valve on the booster that the vacuum supply pipe plugs on to. So even with the engine switched off the booster should hold enough vacuum for several brake pedal pumps. If the booster is not holding vacuum then either it or the pipes to it are faulty.
At idle, with a gas engine, you should have around 18in of vacuum to the booster.
At idle, with a gas engine, you should have around 18in of vacuum to the booster.



