Vacuum leak

gaajet · Post by **gaajet** » 01 Mar 2011, 13:07

2002
V70 T5
140K

A hissing has started from the point where the brake pedal cylinder enters the firewall. When I press on the pedal the hissing diminishes and when accelerating it goes away completely. I know this is a vacuum leak. When I get all the way down close to the floor I can take the accordion boot off and there is a brass rod from the brake pedal that enters a white cylinder which goes through the firewall. The hissing is right there. It is loud enough that I turn up the radio. Any ideas?

Post by **JDS60R** » 01 Mar 2011, 13:47

Vacuum Brake booster diaphragm or valve failure

jda2000 · Post by **jda2000** » 01 Mar 2011, 13:58

do search on brake booster failure, common in these cars.