I'm converting my ATE brakes on my '79 R100RT with Brembo brakes. I've switched out the sliders, but one of them leaks oil. I don't know what year bike those sliders come from and the only number I find on them is No. 1241643. I had to switch out the bolt on bottom of the slider as the ones on the ATE are different that the sliders with the Brembo brakes. The bottom bolt for the newer sliders have a shoulder on them and actually fit into the slider. Does this bolt need a washer? These newer sliders also have a drain plug and a ring on the bottom of the slider (see picture). I don't think the oil is leaking from the bottom bolt or from the drain plug. Is there some sort of seal that may need replacing if I take the big ring off? Appreciate any help. Thanks!