Acorn window type pivot blocks

Question

These photos are from one window - left and right side. They were very tight to get out and I had to really push them. I'm thinking that theywere possible oversized replacements. The original wondows ( picture attached) were installed in 1981. Thanks for any help.

Paul · Accepted Answer

Acorn Window Company replaced both of your pivot shoes with the 15-015 before they went out of business. The reason the old shoes might be tight when removing from the window track might be because the center cams are not in the horizontal position. The photos show them in the vertical position, which extends their brake.