On my 82 300SD with 298k miles, it was a combination of a vac pump that wasn't pulling spec vaccum and a crack in the brake vacuum can. Symptoms exactly as you describe. New pump and repaired (via epoxy) brake vac can fixed it. Warn't cheap, but it worked. I'd get a shop to check the vac pump vac directly. If it's in spec, then chase the leaks. If it's not, you'll need a new one anyway. It gets nerve racking not knowing whether you have brake assist or not.
Dan _______________________________________ 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
