Looking for brake assembly for an Echo CS-300, 301 or 341

[Erwin]

All, I have been using a rule winch with a Echo CS-300 powerhead for years. I've been very happy with it except it does not have a brake or something to stop the drum from slipping when you stopped pulling. I figured out that if I put the original safety brake on it I can activate the brake and hold the tension for me when I stop pulling. If you have a part saw with a safety brake assembly still good, please let me know. I'm really interested. Thanks. Erwin in St. Louis MO