Awesome thank you for your help l really appreciate it!Haase brand racekarts have brake Calipers made by Runner.
I don't see your your caliper model# listed on their site, but I'm guessing your kart is one of their older models and their website only lists parts for their newer karts. They probably still have parts for your Caliper, but you'd need to call or email them and ask.
Here's a link to the Hasse website parts catalog: https://www.haase.it/catalogo_ricambi.php?ln=en&cat=57&categoria=REAR BRAKE CALIPER FR14&dis=57.png