I don't know of online access to the FAM? You can get them on Amazon for about $35.You really need one, but here's the page I mentioned.
Here's what the parts list shows for the pull back spring. 6-9/16 free length with 50 coils. Supposedly the same spring for 47-54 pickups. There's an extension rod that's about the same length. I'll go try and find the box that mine are in after a bit.
FYI, the parts list says that 2 piece rods were used in production, but replaced by the one piece rod in service. The front rod extends thru the cab support, which made probably make it easier to install that rod before setting the cab on the frame. Then just the rear rod needed to be connected to it after the cab was installed instead of threading the longer rod thru the front cab support from underneath.
Attachments
Park brake pullback spring.jpg (49.74 KB, 110 downloads)
IMG_6359.JPG (390.97 KB, 105 downloads)

Last edited by klhansen; 10/05/2023 7:10 PM. Reason: added pic

Kevin
1951 Chevy 3100 work truck
Follow this saga in Project Journal
Photos
1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.