EATON Detroit Spring

The leading manufacturer of leaf and coil springs for the street rod and restoration automotive industries

We Help Maintain American Icons by Manufacturing Leaf and Coil Springs Right Here in America

Phone: 1 (313) 963-3839
Fax: 1 (313) 963-7047

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      We have been manufacturing springs for American vehicles for over 80 years. Our process and expertise has been continuously refined and improved over the century and our Spring Tech section reflects some of that specialty knowledge.

      Browse our many articles, watch videos produced in partnership with AutoRestoMod, and learn all about your spring suspension here.

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  • Click to Call Now: 1 (313) 963-3839
MENUMENU
  • Home
  • Products
    • Suspension Parts
      • Leaf Springs
      • Coil Springs
      • Shocks
      • Attaching Parts And Hardware
      • Installation Kits
      • Leaf Spring Shackle Replacement Kits & Parts
    • Street Rod Suspension Parts
      • Mustang II Front End Springs
      • 48 Inch Truck Springs
    • Allstate - Chrysler
      • Allstate
      • American Motors
      • Bricklin
      • Buick
      • Cadillac
      • Chevrolet
      • Chevrolet Truck
      • Chrysler
    • Daimler - Ford
      • Daimler
      • DeSoto
      • Dodge
      • Dodge Truck
      • Edsel
      • Ford
      • Ford Truck
    • GMC - Jeep
      • GMC
      • Honda
      • Hudson
      • Hudson Truck
      • Hummer
      • International
      • Jeep
    • Kaiser Darrin - Nissan
      • Kaiser Darrin
      • Kaiser-Frazer
      • LaSalle
      • Lincoln
      • MAHINDRA
      • Mercury
      • MG
      • Nash
      • Nissan
    • Oldsmobile - Rambler
      • Oldsmobile
      • Plymouth
      • Plymouth Truck
      • Pontiac
      • Rambler
    • Sterling - Willys
      • Sterling
      • Studebaker
      • Studebaker Truck
      • Toyota
      • Willys
    • Request A Custom Quote
    • Search For Parts Here
  • Spring Tech
    • Learn About Leaf & Coil Springs
      • Spring Tech Articles
      • Tech Questions
      • Spring Tech Videos
      • Featured Elsewhere
      • EATON Detroit Spring Podcast
      • Buy Ford Manuals
    • Spring Tech 101

      We have been manufacturing springs for American vehicles for over 80 years. Our process and expertise has been continuously refined and improved over the century and our Spring Tech section reflects some of that specialty knowledge.

      Browse our many articles, watch videos produced in partnership with AutoRestoMod, and learn all about your spring suspension here.

    • Browse By Topic
      • Leaf Springs
      • Coil Springs
      • Attaching Parts
      • Ride Height & Stance
      • Ride Quality
      • Manufacturing Springs
      • Replacing Springs
      • Modifying Springs
      • Ordering Springs
  • About Us
    • About EATON Detroit Spring
    • Customer Showcase
    • Send Us Photos Of Your Ride!
    • Free Stuff For Car Shows!
    • Facebook
    • YouTube Channel
      • Spring Tech Videos
  • Order Here
    • Lookup & Purchase Your Vehicle's Parts
    • Request A Quote
    • Email Our Sales Team
    • Dealer Information
  • Find Parts That Fit Your Vehicle
  • Click to Call Now: 1 (313) 963-3839

Trans Am Build Dates

Q -Mike,

I have a 70 Trans Am without A/C. I looked up the front springs on your web site and saw that the build date of my car determines if I use spring number MC1222 or MC1294.

I don’t know the exact day of manufacture but the car was made in February. What are the differences in the springs? – Mike

Mike,

It was not uncommon that car manufacturers would make running changes during a model year. Many times the build date was not that critical, however, and just your luck, this time it is because there is a rather large difference in the springs.

The MC1222 has an inside diameter of 4.080 Inches with one square end and one tangential end.

The MC1294 has an inside diameter of 3.625 Inches and both ends are tangential.

Bottom line, the springs are not interchangeable due to the inside diameter and end type.

The cup on the A arm holds and locates the spring and the end type locks the spring in place.

There are 2 ways to figure which spring you need. 1st is by the Body Number Plate. The last code numbers on the left side of the plate, just above the rivet hole is the build date.

The numbers is the month, February is 02, and the letter is the week of the month.

A=1st week, B=2nd week, C=3rd week, D=4th week, E=5th week.

With any luck yours will be clear as to what time of the month.

If the code falls right around the 10th of the month then you will have to use the 2nd way to determine the correct spring.

This means taking one of the springs out.

The cup on the A arm locates the spring and because different strength springs can use various wire sizes the inside diameter of the spring is the important measurement.

The easiest way finding the inside diameter is to measure the outside diameter and the wire diameter.

Once these are known subtract 2 times the wire size from the outside diameter to get the inside diameter.

I hope this has been clearer than mud and helps you.

Mike

Filed Under: Tech Question Tagged With: Collector Car Tech, Ordering Springs

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OEM Replacement & Custom Springs

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How To Order Springs For Your Vehicle

To find the correct springs for your vehicle, you need to provide as much information about your car as possible. There is no such thing as a one-size-fits-all spring.

We try to make this easy by providing many ways to order your springs and send in as much information as possible:

  1. Call Us at 1 (313) 963-3839
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WARNING:

This product may contain chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm.
www.P65Warnings.ca.gov

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EATON Detroit Spring, Inc.
1555 Michigan Avenue
Detroit, MI 48216
Phone: 1 (313) 963-3839
Fax: 1 (313) 963-7047
Email: inquiries@eatonsprings.com

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