You didn't mention which model Brother you have. It appears from
Is there an easy way to remove yellowing from old Brother sewing machine? that is a mostly plastic machine. Plastic is easily cracked, chipped and broken.
I would agree with QuiltMom2 that if you could find a complete vintage all (or mostly all) metal machine machine that can be easily maintained, that would be would be the way to go. It might be difficult to find a good used machine where you are. Here, one can sometimes find an older model traded in at a sewing machine shop.
Looks like you posted while I was trying to compose. I do understand about risky buying used.
Janey - Neat people never make the exciting discoveries I do.