Asalamu Alaykum, i wish to clarify this issue more:
Firstly, the most important part of Islam for a Muslim is the Shahada. Without which nobody can be a believer.
"To bear witness that Allah is the only deity worthy of Worship, and that Muhammad was his last and final Messenger"
Accordingly, we must believe in the Sunnah of the Prophet. This is what the last section of the Shahada necessitates. The sunnah being the words, actions and approval of the Prophet Muhammad (SAW).
Also, our Love for God means we obey the Quran, which clearly shows in many places that we must also follow what the Prophet Muhammad taught. For the Prophet did not teach anything other than what he was taught from Allah (most high).
Not taking the hadith, is therefore a big sin, called kufr (minor disbelief). Which can lead one to Disbelief. Disbelieving in a hadith is total kufr, which takes one out of Islam.
Islam is complete religion, Allah says in the Quran:
This day have I perfected your religion for you, completed My favour upon you, and have chosen for you Islam as your religion. - [Quran 05:03]
Therefore, no matter if there are weak hadeeth(of which there are varying levels) it has no affect on Islam. All the evidence and everything we need to know to follow Islam is there, for us, as clear as the night and day.
As pointed out in my post on the forum, the Quran itself explains the existance of the Sunnah.
The Quran also tells us to go to the people of knowledge, i.e. the Scholars, if we ourselves do not know something.
Another important point is that the Sunnah explains the Quran. A lot of classical tafsir (Quranic exegisis, such as at-Tabari etc) are based upon Hadith.
Unfortunately, there have been some strange groups during the last 200-300 years with ideas which contradict Islam. Changing Islam to suit their own view points. Many of whom, used this as an opportunity to belittle the Quran and the Prophet
by proclaiming themselves to be Prophets.
Not having the sunnah, would lead to the rejection of other Islamic sources and viewpoints. All this can lead to innovation in the religion, if not total abandonment of islamic practises.
Nevertheless, even from a technical standpoint their views fail to be valid.
It is not upon us to look for weak hadith or concern ourself with checking hadith. This is for the scholars of Hadith to do. Hadith checking, analysing and research is a Science. There are many rules and issues involved in this field. There are over 100 different branches of knowledge simply in this one field of Science of Hadith. And each of those branches requires immense study and will have a 100s of books dedicated to it.
Imam Bukhari, Imam Muslim and many other great scholars of the past were experts in all these fields! They spent years travelling gathering hadith and making compilation of the hadeeth into a set series of Hadeeth books.
This has vastly improved our Islamic resources and aided many scholars in their works after them.
Islam is easy and simple to follow. All our actions can be traced back to the Quran and the Hadith. Whether or not a hadith is used that is authentic is not such an issue in practise, because of the scholarly works that do exist that point out the flaws in any chain of narration. etc.
One merely has to accept correction when presented with concrete reliable evidence.
InshaAllah, things will soon clear up for you and you will realise how Hadith are and how things work in Islam. And how simple Islam is!
I ask Allah to help us all and keep us on the right way.
If you do have any more questions, inshaallah i will do my best to answer and help out.
The Following is a good link, it talks about how many of the Prophets who came before did not have a specific book revealed to them to give to their followers, such as the Bible, Torah and Quran. Therefore, the followers of those Prophets had to be following the Sunnah of those Prophets. Please do read it,
That which has been Revealed to us, The importance of the Sunnah
Wasalam.
Ameer.