What Am I Riddles

Question: What has no beginning, end, or middle?

Question: Paint me up to look real good,
Then take me to the shop to maintain under the hood.
Use a small brush to make no mistake,
Or just replace me with something fake.

What am I?

Question: What goes up when the rain goes down?

Question: You bury me when I'm alive,
and dig me up only when I die.

What am I?

Question: What has four legs and can't walk?