Switched out my patio door locking handle but new locking mechanism very stiff

As the title says I switched out my old patio door handle/lock for a new one as the locking switch broke off on the old one. I bought the new handle from the window mfger that made the door. It was identical to the old one as far as holes and placement, but after putting it in and testing it the lever to lock and unlock is incredibly stiff making me worry that it could snap again. If I take it apart what should I be looking for to get it more relaxed?

 

I see it’s been a while since you posted, but I just wanted to ask—did you ever try loosening the screws slightly after installation to see if the stiffness improved? Sometimes overtightening can bind things up just enough to make the mechanism harder to move. Also, did you check if the locking rods were moving freely without the handle attached? Curious to hear where you landed with this.

 

I had a similar issue when I replaced my sliding door handle - the new latch felt really stiff even after lining everything up. Turned out the mortise lock was slightly off-center, just enough to add resistance. If you're in Canada, I reached out to thelockdoc.ca and they helped me figure out the positioning over a quick call. Super knowledgeable and saved me a lot of trial and error.