Rebbetzin Goldenpickanicerscreenname,
“Going to a kever (like kever Rochel) and asking the t zaddik to help you – to davening for you…sounds soooo LUBAVITCH.”
Whether intentionally or not, you are blurring the line between permitted and forbidden, which is a dangerous thing to do. To pray to a person is absolutely forbidden according to all opinions. And I think most opinions hold that to directly ask a dead person to pray to Hashem on one’s behalf is also forbidden. Instead, one should pray to Hashem for mercy in the merit of the person buried there. Why then go to the kever? Because 1) there is an increased level of kedusha there, 2) it builds a more tangible connection between you and the person buried there, and 3) more generally, visiting kevarim reminds a person of his mortality, which can help spur teshuva.
As for seeking the help of a living tzaddik – there is no issur to ask someone living to daven on one’s behalf, or to seek a psak, bracha or advice. This is not setting up an intermediary. You still go to mincha after seeing the tzaddik and daven, and perform your own mitzvos. If, however, one CV”S start praying to the tzaddik, or thinks that it is he who has the power to help, that’s a dangerous error.