Sash balances for 1950s not tilt windows

A home owner from USA says:
February 26, 2018
Just want a be sure I get the right replacement sash balances for these windows. House is from 1951. Appear to be 27" x 5/8"? The ones that have broken have fallen out of the bottom of the sash then gotten bent. No visible markings on the balances, seems like aluminum exterior with steel springs. Thanks!
Spiral balance
Profile picture of Paul
Paul from SWISCO responded:
March 1, 2018
Thanks for posting. For old wood sashes like yours, we recommend using our Series 500 spiral balance and 17-012 bracket. If you need help reinstalling these balances, please let me know.
A home owner says:
March 1, 2018
Thank you. Is 27" the correct size to order?
Profile picture of Paul
Paul from SWISCO responded:
March 1, 2018
Yes, the S500-27 would be the size I'd go with.
A home owner from HI says:
March 16, 2018
Trying to install the 500 series balances with the 17-012 bracket, but the bracket won't stay on the end of the spring. Am I missing something? The balances I'm replacing have pins through the bracket-spring junction.
Profile picture of Tom
Tom from SWISCO responded:
March 16, 2018
The 17-012 should just hook to the butterfly clip at the end of the Series 500 spiral. There's not really any trick to it. Where exactly are you running into problems? 
27" Series 500 Spiral Balance
27" Series 500 Spiral Balance
S500-27
$9.42
Bracket, #32
Bracket, #32
17-012
$1.20
Spiral Balance Charging Tool for Non-tilt Windows
Spiral Balance Charging Tool for Non-tilt Windows
75-005
$12.10
#8 x 1" SS Philips Pan Head Screw
#8 x 1" SS Philips Pan Head Screw
33-017
$0.21
#8 x 3/4" Philips Pan Head SS Screw
#8 x 3/4" Philips Pan Head SS Screw
33-090
$0.27
How to Identify a Replacement Spiral Balance
How to Identify a Replacement Spiral Balance
VIDEO
WATCH >
How to choose the proper spiral balance tip color
How to choose the proper spiral balance tip color
GUIDE
READ >
How to adjust a spiral balance on a non-tilt window
How to adjust a spiral balance on a non-tilt window
GUIDE
READ >
Reply to Thread
Use this form to ask a follow-up question or to share your experience regarding this subject.
(your email address will be kept private and is only used to inform you when a response has been made)
Current wait time is 3-4 business days
We promise that one of our experts will personally get back to you as soon as they are able. Thank you very much for your patience and understanding. If your inquiry is time-sensitive, please feel free to reach us at (888) 991-1929 or at help@swisco.com.