Check out the actuators for the HVAC doors... I believe leakage is part of the design on many GM systems, and this may use similar components. The brakes will actually "use" the vacuum on each pedal press, causing the need to "replenish" the supply. Maybe you should get a little venturi tube mounted somewhere with an anti-reverse switch to build some vacuum while the vehicle is in motion? -Dave ________________________________ From: DMCForum@xxxxxxxxxxxxxxx [mailto:DMCForum@xxxxxxxxxxxxxxx] On Behalf Of Bob Brandys Sent: Tuesday, April 08, 2008 7:36 PM To: DMCForum@xxxxxxxxxxxxxxx Subject: Re: [DMCForum] VACUUM DIAGRAM Vacuum leaks are a plague on electric cars. I was very surprised to find out how the D's vacuum components "normally" leak. The mode switch circuit is terrible. I have isolated just the power break unit and the vacuum storage canister and they have a slow leak that requires the vacuum pump to run every 30 seconds. Dave has the same issue. I suspect the vacuum storage tank leaks. We be testing it soon. and let the group know. Bob [Non-text portions of this message have been removed] ------------------------------------ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/DMCForum/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/DMCForum/join (Yahoo! ID required) <*> To change settings via email: mailto:DMCForum-digest@xxxxxxxxxxxxxxx mailto:DMCForum-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: DMCForum-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/