Malfunctioning part

Question

My channel balances look to be intact, but when the window is installed, the pressure on the left side channel, Balance is insufficient because this plastic piece is flexing instead of staying tight and rigid. I think I just need to replace this plastic part. Can you tell me what it is?

Jasmine · Accepted Answer

This piece is the top sash guide. I believe you have the 18-181 Window Sash Guide. To determine if this is the correct replacement, carefully look over the specifications and compare them.

Detail of 18-181

Side view of 18-181