Me and my brother own my deceased parents house and property under a trust set up by our parents.
Please elaborate as to exactly what this means.
How is the house titled? Please be specific (but don't use real names). Please start by providing information about the trust. Who created the trust? I'm guessing it was both of your parents. Let's call them John and Mary Smith. I'm also guessing that, when they were alive, they were the trustees. That probably means that, when they were alive, title was something like the following: "John Smith and Mary Smith, as Trustees of the John and Mary Smith Revocable Family Trust." Is that about right?
When did the first of your parents die? When the first one died, did the second one record with the county recorder an affidavit of death of trustee? Same questions about the second to die. Also, who is/are now the trustee(s) of the trust?
Are you and your brother the only beneficiaries of the trust? What does the trust say is supposed to happen upon the death of both of your parents?
In your follow up post, you wrote that there is an "attorney administrating the trust." Logically, that can only mean one of two things: the attorney is the trustee or the attorney represents the trustee(s). Is the attorney the trustee? If not, whom does the attorney represent?
There's a old vehicle, which is not part of the trust, abandoned on the property that will sold for parts.
Did your parents have wills? If so, and assuming that the will of the first to dies said everything would go to the survivor, what did the will of the second to die say was to happen to estate assets? It would be common to have a will that says, in effect, everything not already in the trust goes to the trust (a pour-over will).
Is it a simple procedure to deposit those funds into the trust's bank account, or is complicated accounting required?
The act of depositing money is quite simple. Whether it's appropriate depends on how you answer the questions I asked. Careful records of all financial transactions should be kept, but I wouldn't call that "complicated accounting."
The funds will be used to purchase building materials when I do some remodeling work to the house at the end of the year.
If you're not the trustee, why are you doing remodeling work?
I would like the trust to be modified, if possible or replaced with a new one.
Unless the trust was expressly created to allow modifications after the deaths of your parents, modification isn't going to be possible. Whether a transfer to another trust would be appropriate isn't possible for us to determine.
A trust becomes irrevocable upon the death of the trust maker.
Sometimes that's true; sometimes it isn't. We don't have enough information to know what's the deal with the trust in question.