Okay, I've been putting off this response to the OP because I've been busy, and haven't wanted to go to the trouble of digging out the necessary reference books. I think it's past time, though.
For our purposes, the dictionary defines "conservative" thusly:
Tending or disposed to maintain existing views, conditions, or institutions : traditional; marked by moderation or caution
I chose that definition from the several available because it is foolish to even attempt to pretend that our Founding Fathers belong to or fit into modern political parties and groups, and definitions relating to style, taste, and manners are irrelevant to the discussion.
Now, then. The argument goes that because our Founding Fathers staged the American Revolution to throw off British rule, that must make them "revolutionaries" - in the modern sense - and thus radicals, aka liberals. But does that chain of logic necessarily always follow? Is revolting against the government always radical and liberal?
Most people in this country, when they think of the causes of the American War for Independence, dredge up the phrase "no taxation without representation". In fact, this principle was only part of a larger conflict. The American revolutionaries were actually fighting to preserve what they saw as the traditional
status quo, the rights that British citizens were supposed to be guaranteed, and which they felt were being encroached upon.
In arguing against the new taxes Parliament was imposing on the colonies, John Adams described them as "an unconstitutional innovation".
The Braintree Instructions
Patrick Henry's proposed Virginia Resolves established clearly that the colonists' objection to the Stamp Act was based on the change and novelty of the law to the rights of Englishmen - which they were at that time - under standing British law.
Virginia Resolves on the Stamp Act, 1765 May 30 While Virginia's legislators only approved five of the resolves, and later rescinded their approval of the fifth, Rhode Island's legislature copied and approved all seven.
The Stamp Act Congress of 1765 met to draft a joint statement of grievances for the British government, and in it, they protested that their ancient, chartered rights were being violated.
In other words, it is very clear that the American Revolution, unlike the French Revolution (for example), was based not on the desire to radically revise and restructure society, but on the desire to maintain traditional rights and legal customs that had been guaranteed by existing laws for centuries. That is to say, it was a
conservative revolution.