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Problem Doing Frame Measurements

J

jtfx6552

Member
I'm working on an "in the family since new 65 fastback". I know it was never hit in the back. When I started on it, all the body panels lined up as well as any mustang I've ever looked at.

When I try to measure the rear most spring mounting height, I'm off by over an inch. I must be doing something wrong? I keep checking and rechecking and can't figure it out?

The car is upside down right now, I ran a string spaced from the bottom of the car per the drawing in the shop manual. I started with the steering frame holes to set the front of the line away from the centerline of the steering hole 10.68", then lined it up with the rear spring front hanger (away 8.14"), but the rear spring hanger comes up at 16 ish, rather than 15.13".

Anyone have any ideas?

Note, I just laid the carpenters square in there for the picture to show what measurement is off, I am using more accurate methods for the "real" measurement.
 
Do the rest of your measurements match the datum line?

Do your hole to hole measurements reflect the same? If it's really that much higher in the rear, the length should be long when you measure the square of the rear rails.

Lay it on it's side and remeasure it. See if it changes.

You should be measuring it right side up sitting on stands placed near the torque boxes.
 
1965/66 frame measurements are incorrect as published in the Ford Shop Manual...ask me how I know!
 
"Midlife" said:
1965/66 frame measurements are incorrect as published in the Ford Shop Manual...ask me how I know!
Click to expand...

All of them or just the ones from the datum?
 
I found the lengths to be several inches off, which does not give me confidence in any of the other supplied measurements.
 
If you can't trust the measurements in the diagram, I would measure the diagonals for square. If the car fit together ok before it had to be pretty close.
 
Thanks for the quick replies.

I have been reviewing the set up for about the 1000 time. I am convinced that other than a general lack of precision, there is not a flaw in my measuring technique. Having said that, I'm sure I'm accurate within a 1/8", probably even a 1/16".

I'm having trouble finding a picture of the car assembled from the back, I just can't imagine the frame rails being off and inch, see the attached.

I remember seeing another dimension diagram floating around the web, one that had like a hand drawn font for the dimensions. maybe I'll see if I can find that and what it says.
 
Ok,

I found the "other" drawing. The Datum seems to be at a different height from the bottom of the car. I'm not sure if it is parallel to the datum shown in the shop manual. I'll have to go down and see what i can find out...
 
Further research, I guess for anyone that may stumble upon this thread...

The dimension in the shop manual must be wrong.

I added a string for the "George W Lisky" datum. See attached pictures for both datum strings, sorry white string in a white garage is a little hard to see.

I measure 11 3/16" to the frame rail, almost matching Lisky's 11 1/4". In later Lisky diagrams, notably the 1970, he lists 11 3/16", so I think their 1964-1965 drawing may have been off a little as well.

It's a shame Lisky doesn't give more information, they don't say exactly where on either frame rail to measure, and the datum is not parallel to either, so a little guesswork was required.
 
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