Opener Azhar Ali paced Pakistan's first innings with a patient century as he and Asad Shafiq built a crucial Boxing Day Test partnership.
Pakistan were in some trouble at the start of day two on 4-142, but Azhar and Asad took the score to 232 at lunch.
Melbourne's weather continues to cause trouble, with a short rain delay before Azhar brought up his first MCG Test ton.
Rain also forced lunch to be taken a few minutes early.
Azhar was on 112, his 12th Test century, and Asad had followed up his first-Test heroics with 48no.