Asked my Manager for Promotion!!!

I work as a technician in a battery manufacturing plant. I come under union so BS like salary hike and promotion after 2 years happens plus they only care about seniority. Now I have worked my ass off, finishing projects, going above expectations so many time and I feel like I deserve more hence I asked my manager for engineering role. He replied “ I will think about it” and completely vanished we do not see each other often so I don’t know what is going on. I don’t want to bug him by asking repeatedly but on the other hand he did not even mention if I need to improve on any of the skills.

Edit - other co workers asked him within past 6 months and he replied differently to everyone. Saying there is an hiring freeze, wait for some time, etc. they also said it’s not worth asking him because he doesn’t pay attention to this matter.

Can anyone tell me what todo here