[DaveNP]

I replaced my front hoses with stainless overbraided ones from Pirtek, getting the old connections apart was a pain, looking back I think it was because the original male fitments had a short threaded section with a clear shaft behind it which allows the lip of the female to accumulate dirt and corrosion, using a 1/4 turn forward 1/8th turn back to ease it undone would possibly help. While Volvo used a superior solid line the connectors seemed to be made of a soft brass which does chew up easily. I ended up replacing one of the hard lines back to the ABS unit to overcome the problem with the connectors.
The lines I got did not have the rubber collar half way up the hose to help prevent it rubbing so have an eye to how it fits and/or touches going lock to lock.