Weak for the last six inches

My 68 GS400's top is close to new, and everything works. I need to give it a little help by hand to get it closed. I can't see anything wrong with the frame. Any ideas for cheap / temporary fixes I can try? I'll probably take everything apart, inspect and test, etc. next spring but I'd like it to work a bit better between now and then.

Thanks!

 

Can you completely close it with help?

 

Did you check the fluid in the pump motor???