Jay Honeck wrote:
Doesn't it seem just a little weird to lose both vacuum instruments in a six
week period? Is there any way my vacuum pump could still be putting out 5
inches of suction, and somehow sending junk into the instruments? Could the
AI failure last month have influenced the DG failure this month?

If the (dry) vacuum pump fails catastrophically, it can barf chunks of vane
material back into the regulator and instruments (the instrument cases act as
vacuum reservoirs, and will suck air back into them if the outlet pressure jumps
back to ambient.)

Also, some vacuum hoses are prone to deterioration with age and can shed junk
into the instrument inlets (especially if the hoses are flexed and/or wiggled,
as happens when an instrument is replaced):

http://www.avionicswest.com/myviewpo...umarticle.html