Also consider the plastic beading strip between the wings and body. As the car flexes these rub and can squeak. Some use ACF50 which is a very good anti-corrosion oil, other 3 in 1 oil. I would avoid WD-40 as it is hydroscopic (absorbs water). Personally I used ACF50 applying with a small syringe along the beading and wiping any excess away with a cloth.

As other have said also check the rear springs and make sure they do not rub and woodwork also shackles and bolts, also shock absorber bolts can become loose.

Adrian

Buggered Off, to a modern none leaky car, heart's still ticking