Both KTM and Bajaj service centers did not have the new part so had to clean and reuse the old seal.

BHPian SunnyBoi recently shared this with other enthusiasts

Next up the rear brakes. I went to a Bajaj dealer and I got a seal kit for a pulsar. Pretty much all Bajaj and dukes use the same rear caliper so it should work, hopefully. I popped into the KTM dealership and got a couple of new front caliper bolts since the old ones looked tired. Once I was back home, I remembered I should have gotten a new battery belt as the one on the bike now was close to breaking. Oh well, there is always a next time.

First step was taking off the wheel. I had never taken off a rear wheel before - I struggled a LOT with it. I just knew for some reason I'd suck at this and I did not disappoint myself heh. Hopefully, I don't ever have to remove the rear wheel again!

Took off the old rotor and ABS ring. This is 9 years of muck hidden behind the rotor.

Things weren't so clean on the other side as well. There was a TON of rubber powder? as well as melted rubber.

With the wheels done, I focussed back on the caliper. I made sure I removed the pads and extended the piston as much as possible by pumping on the pedal as much as possible. I pulled out the caliper and found the insides pretty clean with only a few black flakes.