Front brakes shudder when applied at high speed. Brakes are new with approximately 5,000 miles using premium parts. Low speed, brakes work fine with no shuddering. problem just started this past week. Haven't had a chance to take a look but will do so next week. Any tips on what to look for. I did the brakes myself using all new parts except for calipers. Thx in advance for any good advice.