Spring Markings

As I progress through the next steps to installing the drive train and engine, I'm going through suspension parts to make sure that everything is done and ready to install.   Gotta have the suspension installed prior to installing the engine of course.  Searched for pictures that I took of the rear leaf springs before restoration because I remembered that there were some interesting paint marks on them that I wanted to recreate prior to installation.  Here they are after soaking in Evaporust.  The top two pictures show the bottom of the uppermost leaf springs, with white paint going the entire length of the spring.  The way its done on the two is very different. 

 The bottom two pictures, above, show a single white dot on each spring.  On the right the dot is partially obscured by where one of the straps rubbed it off, tape measure shows that the one on the left is about 16 inches aft of the centering bolt.  Below is a wider view of the whole spring showing the location of the paint daub.

Front coil springs were black (dipped these in paint many posts ago) now ready to apply the top to bottom chocolate brown stripes on each along with the white stripe on about half the length of each spring, which according to period Ford literature:  "The Load Pounds figure shown indicates the mean load.  Usually, there is a variance of 30 to 50 lbs. plus or minus of the load pounds indicated in the chart.  If the tested load rate is on the mean to low limits, a white stripe is shown in addition to the other identification markings."

 You can see the chocolate brown stripe to the left of the white on the right hand spring above and below.

So apparently the tested load rate for these springs was on the 'mean to low' limit.  The Ford spring chart shows that brown indicated a mean load of 1516 lbs, so these must have tested 30 to 50 lbs. below that.  The 1516 spring rate is the highest available at the time for a Mustang and was indicative of the Special handling package that came on the K code convertibles.  What's interesting is that the chart shows the same spring whether the K code had power steering or manual steering (but power steering wasn't an option for the K codes, supposedly).   So it would make sense, although the chart doesn't specifically indicate it, that a K code convertible without power steering would be expected to weigh-in 30 to 50 lbs less without the power steering equipment so springs that tested to the low end of the mean load rate would be chosen...pretty cool that they were trying to match the springs so accurately to the particular car.  So for this car they chose springs that were in the range of 1461 to 1481 lbs.  With this car being one of the first K code convertibles that the assembly line had seen, they wouldn't have known that there weren't any power steering K-codes - so given what we know about no options for A/C or power steering, we would expect all 64 1/2 K code convertibles to have been delivered from the factory with springs of this type, with the brown and white identification markings.

 Of further interest, the chart shows that the same spring is used on K code convertibles with A/C (again supposedly not an option for K codes), but in combination with a C4DZ-5355-A shim which somehow brought the spring rate to 1491 lbs.