This is well worth reading. It delves into topics from Vatican II to the traditional Latin Mass and the authority of the Roman Pontiff. Letter of Pope Saint Paul VI to Archbishop Marcel Lefebvre
Please discuss or ask questions here, rather than at the linked site.
Notice the paragraph where Pope Paul asserts that some teachings of Vatican II are infallible.
Also, I tweeted this:
Eastern Orthodox: “We’re right and the Pope is wrong.”
Protestants: “We’re right and the Church is wrong.”
“Old Catholics”: “We’re right and Vatican I is wrong.”
SSPX: “We’re right and Vatican II is wrong.”
TLMs: “We’re right and the Pope is wrong.”
— Oh, look! A circle! —
It’s always the same. The big bad Church is being mean to us by teaching us divine eternal truths that we don’t like. The mean old Pope is making us attend Mass without letting us control every aspect of it. These persons who rebel against the Church never win. History always shows them to be heretics and schismatics.
Lefebvre never reconciled to the Church. And I think he had rather narrow views on salvation. The Council of Florence taught that schismatics and heretics are damned to Hell. But we must understand that to mean only if they are unrepentant from actual mortal sin; some could be in a state of grace by a sincere but mistaken conscience. The sad thing is that, on the far right, they don’t allow for that sincere mistaken conscience for Jews or Muslims, and so why should it then apply to them? I think they can be saved, but their own views on salvation are contrary to their own behavior.
RLCJ
the reproach of Christ 
to add to it – Sedevacantist “We are the church since Rome defected”
That is what they think.
just read this again – really amazing – here is a question – Lefebvre complaint that he “does not always see how to reconcile certain texts of the Council” Pope Saint Paul VI said “The precise tenor of the documents, with the totality of its nuances and its context, the authorized explanations, the detailed and objective commentaries which have been made, are of such a nature to enable you to overcome these personal difficulties”. I wonder what documents, commentaries, and explanations he was referring to? Also, was there a direct response to this letter from Lefebvre back to Paul VI? or any letters between Lefebvre, John Paul II and/or Rome?
I don’t think the Pope was referring to any particular commentary on Vatican II. There are a myriad of faithful souls in the Church who are capable of explaining that Vatican II is not in conflict with past teachings. The Lefebvre complaint puts his own understanding above the Magisterium. He can’t see how to reconcile it, so he rejects it. As for myself, I don’t need explanations, I believe based on faith and obedience.