Saab: vacuum pump, vacuum problem, vacuum line

Question
QUESTION: I have a 2000 Saab 95. The vacuum pump, is it supposed to suck or push.  Also I have a hard brake pedal. I think it may be the check valve. Any info would greatly be appreciated.

ANSWER: Lisa:
 As stated in my profile, my hands on experience does not include your model. Any answer is in general terms only.
 Engines automatically create vacuum (sucking action) as they take in oxygen for combustion (akin to human breathing). This vacuum "pulls" on one side of a diaphragm in a chamber called the "brake booster" which energizes your power brakes. So, per your description, you have a brake booster problem...either a blocked or faulty vacuum line or "stuck" check valve (as you surmised).
 The check valve is a one-way valve that permits the vacuum action when the engine is running,but blocks reverse leakage when the engine is turned off, thus allowing a modicum of vacuum assist after the engine stops. Otherwise, the brake assist function would immediately disappear when shutting off the engine.

   Hope this helps,
         Jerry

---------- FOLLOW-UP ----------

QUESTION: Hi Jerry,
Is the booster supposed to have 2 draws, one to the manifold and one to the pump?  We realize the check valve goes to manifold only. Do you think there is a vacuum problem somewhere else on the intake that would cause less draw? (Should draw to manifold and pump be equal).

Lisa Demand

Answer
Lisa:
 Most cars do NOT have a separate vacuum pump these days, although as I'd stated,as I am not intimately familiar withn your model, I cannot be sure in your case. Alas, I cannot answer beyond that for reasons stated.
 I seriously doubt a vacuum problem on the intake side since the engine would barely run if there were.

         Jerry