Joined: Jan 2010
Posts: 9,808
Likes: 1,781
From: Northern California
Bikes: Cheltenham-Pedersen racer, Boulder F/S Paris-Roubaix, Varsity racer, '52 Christophe, '62 Continental, '92 Merckx, '75 Limongi, '76 Presto, '72 Gitane SC, '71 Schwinn SS, etc.
Perhaps the outer anti-rotation washer hasn't quite settled onto the lever boss with the two engagement flats?
It needs to be engaged over the flats, or the washer can rotate, and the screw tightening force won't be able to compress the friction sandwich of the lever between non-rotating washers.