First of all the Orthodox and Catholic Church were one for over 1000 years. They only officially split in 1054.
http://www.telegraph.co.uk/news/worldnews/europe/russia/8790457/Russian-Orthodox-Church-embroiled-in-corruption-scandal.html
http://www.theguardian.com/world/2005/mar/20/greece
http://www.ft.com/cms/s/0/8da92478-8573-11e1-a75a-00144feab49a.html#axzz2mgvf1MBq
http://byztex.blogspot.com/2010/11/monastery-scandal-hits-greek.html
http://www.eurekaencyclopedia.com/index.php/Category:Greek_Orthodox_Abuse
http://greece.greekreporter.com/2013/12/02/scandals-in-the-greek-church-go-public/
These are just some of what I found with a quick search. As far as historically, it would take a little more time, but there were definitely abuses of authority and scandals over the last thousand years.
Any time there are people of authority, corruption is always a danger. Human beings are weak.
The idea that because some popes were immoral and depraved somehow undermines the Church's claim that the Holy Spirit lead the Church, is to misunderstand this claim. God guides and leads even immoral popes. Not in their immorality but he protects them from leading the Church into error and that has been proved over and over. The "bad popes" were so busy being bad, that they never bothered to proclaim any dogma. This is because the Holy Spirit prevented it.
There is the story of one pope who became pope through coercion. He promised the Queen once in power that he would declare the Arian heresy (which she believed) to be divine truth. However, once in power he wrote her a letter and said he couldn't do it. So again, the Holy Spirit protected the Church.
The corruption of some popes only shows the miracle of God's Church and how he has kept his promise that the gates of hell would not prevail against it.