Dear Moderator
It has been mentioned and insisted to me that Archbishop Lefebvre had visited the SSPV and accepted sede-vacantism at later stage of his life.  Accordingly this is not a rumour, is it true?
I am not a sedevacantist just want to have clarification of Archbishop Lefebvre's stand.

God Bless

Thank you Moderator for the clarification. but again they said they have first hand information that Archbishop Lefebvre's did mentioned being a sede in one of his sermons or letters (??) that is why it was brought to court by SSPX to stop the publication.
God Bless

It’s well known that Bishop de Castro Meyer did in fact go sede toward the end of his life.

I was told that he was telling people at the 1988 consecrations that ‘we have no pope’, or something similar.

This is corroborated by numerous sources, including Fr. Schmidberger.  Archbishop Lefebvre was also said to be considering the position but was dissuaded from it by the priests around him.  Bishop de Castro Mayer also made a statement that the perpetrator of Assisi could not be the head of the Church since he is not a member.

Archbishop Lefebvre himself said that both he and de Castro Mayer were leaning toward it after Assisi but “preferred to wait”.

I was told by a priest member of SSPV that they sought episcopal consecration from de Castro Mayer, but he told them to go see Bishop Guerard des Lauriers.

Yes, this was what I was told too, including the SSPV part.

Rumor, innuendo, and hearsay are acceptable forms of "proof" for sedes. One of the reasons why I'd never be one.

This has absolutely nothing to do with whether the position is true or not. 

This has absolutely nothing to do with whether the position is true or not.

I think it does. Since most sedes don't care about actual proof for anything (rumor, inneuendo and hearsay will do just fine), then they don't have to have actual proof for Sedevacanism. Just feelings - the need to feel better about the Crisis. 

True or fase
Archbishop Marcel Lefebvre on the occasion of his Suspension a divinis by Paul VI write the following reflection on June 29, 1976:

“That the Conciliar Church is a schismatic Church, because it breaks with the Catholic Church that has always been. It has its new dogmas, its new priesthood, its new institutions, its new worship, all already condemned by the Church in many a docuмent, official and definitive.
“This Conciliar Church is schismatic, because it has taken as a basis for its updating, principles opposed to those of the Catholic Church, such as the new concept of the Mass expressed in numbers 5 of the Preface to (the decree) Missale Romanum and 7 of its first chapter, which gives the assembly a priestly role that it cannot exercise; such likewise as the natural — which is to say divine — right of every person and of every group of persons to religious freedom.
“This right to religious freedom is blasphemous, for it attributes to God purposes that destroy His Majesty, His Glory, His Kingship. This right implies freedom of conscience, freedom of thought, and all the Masonic freedoms.
“The Church that affirms such errors is at once schismatic and heretical. This Conciliar Church is, therefore, not Catholic. To whatever extent Pope, bishops, priests or faithful adhere to this new Church, they separate themselves from the Catholic Church.”

Six more months on CI, and even you will be a sede.  

I think a sensible person who is not sede isn't saying that sede could never happen, they're just saying that there isn't enough proof yet of the position. For me, I err on the side of assuming Francis is a pope until proven otherwise. I realize neither option is perfect. The R&R have an obedience problem and the sedes have a universal acceptance problem. Both sides accuse the other and both sides are basically correct. Because I can't resolve it, I've leave it to God.
If someday the church declares that the see was vacant during this time I submit. If the traditional clergy ever unite in the conclusion that Francis is not a real pope, I would submit.  If that happens in 6 months? So be it
That said even if that happens it does not necessarily follow that I would accept all of the conclusions of sede as it is usually in historically known. For instance Frances might not be a true pope. But that does not necessarily mean that the other post conciliar Popes were not true Popes, nor does it mean that the new priests and bishops all lack valid orders