Jacking Points Spilt UnderSeal - What To Use To Repair?

Have noticed my OH's 1.6 Sport has split underseal on the two rear jacking points. The seams have surface rust where they are exposed.

Will covering in Hammerite and then covering the seams and sealing with silicon sealant do the job or do I need something more specialised I should use?

Any advice gratefully received. Don't want to go to any great expense as the car is now 12 years old.

Thanks K.

I would get it done properly you need to get rid of the rust and weld the seems

berhb,
The Op did not say the seams were split so why do they need welding?

Keicar,
There will be rust on the surface area particularly where the underseal has worn away from contact with the jack, pretty sure it will not go any deeper, I would wire brush and then reseal with under body sealer or hammerite coats as you suggest. Either of those will be good and should last dependent on how many times you use the jacking point.

Thanks rd1

keicar
sorry mate misread the post

We see this a lot, idiot tyre fitters and their trolley jacks! We wire wheel off the sealant in the area and as much of the rust as possible. If the area doesn't need and welding, we treat the rust with Dinitrol RC900 converter and when this is try, with Eastwood Rust encapsulator. This dries very quickly and we follow it up with polyurethane sealant. If necessary, we then send it to our body shop for any stone chip or necessary cosmetic work.