Window Lifts and plastic parts

Hello,

The bottom fitting of the second balance shown in your photo appears to be missing. If it was identical to the other balances, then you would need either the S351, with a 15-002 bottom attachment, or S390, with a 15-001 bottom attachment. Take a look at the image below to determine which balance you'll need. 

Comparison of the S351 and S390 balance shoes.

Keep in mind that the length measurement should only include the metal channel and not the end fittings. You'll need 2830 spring strength options for the balances stamped with 2830, which should have a 29" long metal channel. 

As for your balances stamped with 2040/30, you may need a 2040 strength option for 21" balance channels but keep in mind that it will carry a window sash between 15-23 lbs. I would recommend weighing the sash that these balances support to confirm that it falls within that weight range. 

It's tough to be sure since your top sash guide is broken but it looks like a match to the 18-008. Take a look and compare the dimensions below to confirm that they match up to your part. Thank you!

Detail of 18-008

Alternate view of 18-008

Great! Just let us know if you need anything else.