In a message dated 3/31/2008 12:49:34 P.M. US Mountain Standard Time, [EMAIL PROTECTED] writes:
What is the spec on the vacuum pump? On mine, with everything but the brake booster disconnected, my Mity-Vac was showing about 23" or so. The testing value for the brake booster is 0.75 to 0.80 bar. using 30" Hg as one bar would put you right at 22-23"Hg Gas engines typically idle at 18-20" Hg, and drop well below that at WOT. That's why the brake booster, and the other systems, have check valves and reservoirs to save some of that good vacuum. I have seen more than one vacuum pump on my 79 300SD pull 20" at idle. This within a few seconds of start up. All the AC and brakes will work fine down to 10-12" or so. I believe you have an intermittent failure at the vacuum pump. A sticking check valve (my guess)or a cracked diaphragm. Chuck's (80 300SD) problem was intermittent and then became worse until he had them change the vacuum pump. I have to say that shop people get lucky and fix something by accident, sometimes, and they sure as hell aren't going to say what it was right after sticking on a new $400 vacuum pump on a car worth 3K. Let us all know what fixes this! Good luck! Jim Friesen Phoenix AZ 79 300SD, 264 K miles 98 ML 320, 155 K miles **************Create a Home Theater Like the Pros. Watch the video on AOL Home. (http://home.aol.com/diy/home-improvement-eric-stromer?video=15&ncid=aolhom00030000000001) _______________________________________ http://www.okiebenz.com For new parts see official list sponsor: http://www.buymbparts.com/ For used parts email [EMAIL PROTECTED] To Unsubscribe or change delivery options go to: http://okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
