Finally did it. I had to remove the seat and get on my back to access it ... what a nightmare ... The worst was actually setting and fitting the brake rod again, because i started screwing these 4 bolts first and of course it didn't line up
Now done. I will test tomorrow and see if my problem is still there. I had every symptom of pad knockback, but i changed everything brake related except the booster (and i say everything ... wheels, wheel bearings, spindles, suspension arms, brake discs, calipers, lines, master cylinder, purged a bazillion times, problem was still there)