Sigma 30mm f1.4 EX HSM Repair help

Hello I have been learning to repair lenses, and have successfully repaired many lenses including vintage primes, modern mirrorless lenses and EF kit lenses.

I am stuck on swapping a front element on a sigma 30mm f1.4 EX lens. I'm a few hours into searching the internet and I haven't had any luck. I can't seem to get the front element off and I definitely don't want to break it.

Any advice would be amazing.


Las Vegas learning lens repair.
Cameras: Canon M5, Canon 6D, Canon EOS t3i
Favorite Lens: Vivitar komine 28mm f2

Also in return I can offer help / advice to anyone trying to repair lenses that I am very familiar with.

EF-M 15-45mm stm
EF-S 18-55mm is ii and STM
EF 35-105mm
Yongnuo 35mm f2
Pentax PK 50mm f1.7 and 135mm f2.8
Sigma 17-35mm f2.8
Sigma 24-70mm f3.5
Vivitar 28mm, 35mm, 50mm vintage primes