On my bike I have the older Shimano 600 side pull brakes. The problem is that they are longer then the current ultegra brakes. So even with my pads all the way up, half of the pads are still to low to reach the full rim. Do i need to replace the brakes or can i safely file down the slit where the pads go into so i can raise the pads up higher. Its hard to explain, but I hope you guys understand.