Best rust preventer on A Class Subframe

[Submariner1]

Thanks to a broken rear spring, I noticed some surface rust on the rear subframe. (See red arrows)
Luckily its just blistering paint and surface rust, quickly rubs back down to shiny steel.
Mainly on the odd edge here and there and the trailing arm has largish areas of surface rust.

I am looking for something that will remove the rust, but not the painted majority. Ideally like to preserve the original painted part of the subframe. So next owner, realises it was just surface rust.

E.g most of the subframe washes off to black solid paint, but here and there, the paint is blistering or cracked; and underneath is surface rust.

Or am I better with a rust converter-neutraliser and primer in one.
And then overpaint with Hammerite ( only because I have a large tin).

anyone used Bilt Hamber Hydrate 80?
It Sounds OK for my needs?

or any reasonably priced recommendations welcome

and a good powerful degreaser to clean off road muck ready to derust/paint

while I wait for new springs to arrive thought I might have a go.

 

[alexanderfoti]

Dynax UB is what I use in the garage.

At that stage on your car, I would hit it with a degreaser underneath on the pressure washer, let it dry thorughly and hit it with 2 coats of Dynax UB.

 

[DREAMER NO2]

I have use a few in the past .Best one i purchased was from - Land Rover blog ,,they use it to convert rust on old LandRovers

 

[DREAMER NO2]

This is the one Metalmorphosis

 

[star]

ACF50 for me.