I scored a nice Corsaro women's road bike at the thrift store last week, but have been stumped today. I was replacing the brake cables and housing and when I stripped off the old stuff, I went to adjust and tighten the brake levers (dia compe with turkey wings). When I tightened them enough so they won't move, the part of the brake lever that rotates inside the hood was hitting part of the clamp (essentially the clamp got too close). This makes it so the lever does not spring back at all. I figured that somebody had just put too big of clamps on too small of a handlbar. I had a bar that was slightly bigger, so I put it on, but the clamps weren't big enough to even fit on the handlebar. All of this had me thinking that there was something more wrong than the clamp being too small. Whatever the problem is, the previous owner had gotten around it by not tightening the levers down very well. Any suggestion on how to remedy this would be helpful, and let me know if you need more detail.
I had the same thing happen once and just stuck a good sized flat bladed screwdriver down inside the lever housing alongside the clamp and gave it a little twist to bulge the housing away from the clamp/lever somewhat (hope that was clear).
The brake lever is aluminum and pivots around a red/blue/gold colored stud. The screw that tightens the brake lever clamp onto the handlebar goes through this stud. I believe that the problem is that the part of the handle that pivots around the stud has been been inward towards each other. To solve this, take a large bladed screwdriver, insert into the brake lever and bent apart. Could be wrong, but I believe that this is the solution to the problem.