98 v70 2.4 vacuum hg off intake manifold

frisky99 · Post by **frisky99** » 23 Jun 2021, 12:37

Hello, trying to diagnose hard brake pedal using a mityvac . I get 20hg holding going to the check valve and 20 hg off the intake manifold. Is 20hg enough vacuum to open the check valve? Thank you, Bruce

frisky99 · Post by **frisky99** » 23 Jun 2021, 13:39

I get 10hg and holding to the check valve.

Post by **scot850** » 23 Jun 2021, 16:47

If your peddle is hard, and engine is running, then chances are that the one way valve has failed. It is a plastic part on the end of the vacuum hose at the booster. They do fail but not often. If you have a junkyard around you might be able to pull one from there.

Neil.

Post by **bmdubya1198** » 24 Jun 2021, 20:30

20 in-hg is normal vacuum for these engines, so that should open the check valve. You probably have a bad check valve.