There are a number of brands with expanding action brackets and the serial number range often cited may not be totally correct. So far I have replaced brackets on Young Changs, Weber, Wurlitzer, PianoDisc and even a Pramberger YC . The early replacement brackets where free or low cost when you provided a serial number to YC and at one time where part of a recall program. The last several sets I have purchased have been from Supply 88 and are excellent. You will need to measure the existing brackets to get the proper size replacements. You may need to drill in order to screw the replacements onto the action frame and you will need to measure and reset the action ratio. You might not be able to see the cracks on the metal but look for bubbles /blisters, hairline cracks, crumbled pieces etc.
You may need to do a bit of regulation to the action and undo changes made before . Take pictures before diving in. Some older pianos prior to the YC piano had expanding brackets Contact me privately if you need help
------------------------------
James Kelly
Owner- Fur Elise Piano Service
Pawleys Island SC
(843) 325-4357
------------------------------