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Old 03-08-2020, 08:28 PM   #1
Daddysearly30pickup
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Default 12 leaf front spring in 82A pickup

I've seen references and replacements for the 82A pickup that are 10 leaf, but have not seen 12. Just wondering if this was an option, a modification or what.
Any one else have similar or information?
Thanks
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Old 03-08-2020, 09:15 PM   #2
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Default Re: 12 leaf front spring in 82A pickup

Ford period accessory for both cars and pickups offered "for vehicles in heavy service."

Service Bulletins P.510 November 1930.

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Old 03-09-2020, 09:16 AM   #3
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Default Re: 12 leaf front spring in 82A pickup

Folks also performed shade tree repairs for sagging springs. A check of the spring pack comparing it to Marco's chart may answer the question better.
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Old 03-10-2020, 02:35 PM   #4
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Default Re: 12 leaf front spring in 82A pickup

Quote:
Originally Posted by rotorwrench View Post
Folks also performed shade tree repairs for sagging springs. A check of the spring pack comparing it to Marco's chart may answer the question better.
Well, he did ask about the front - to my knowledge nobody has "scoped out" the front spring engineering-wise.

I bought an "aftermarket" front spring to use under my pickup one. Aftermarket as in what was available at the time from JC Whitney. This was back in my early days when money was tight. Advertised as a "Model A front spring," in comparison with an actual Model A front it was a "stout" thing.

The leaves were all similar staggered lengths and the "eye to eye" dimension was similar. But in a "lets see if this thing is stiffer test of a 200lb mechanic and the garage floor," there was a considerable extra margin of stiffness in the Repop.

I noticed that all the spring leaves of the repop were the same, and thicker than the original in all cases - the Original Model A Front springs were "varying" thicknesses.

I concluded "aftermarket replacement" was an apt term for this spring - and I think in reality the spring was a boat trailer spring someone found similar in dimensions to the Model A spring.

Two certain ways and one bonus way to tell on these: 1) the top leaf is frequently not "champhered" where it fits into and hits the sidewalls of the groove in the front cross-member. Many restorers of that era in writing about springs (Rick Freeman comes to mind) recommended grinding off the spring corners to remove the defect. 2) The individual leaves are not "tapered" at the ends. 3) They most commonly come without spring-clamps, although this may be common of even "OEM springs."

Its too bad there is not more engineering information available on the original front springs. As designed and implemented by Ford, one describes the original front springs as "close to the envelope." Generally, if there is a problem with sagging or broken springs, it is the front that is involved. It also is a major contributor to ride and handling, perhaps Ford's motivation for "close to the edge?"

The boat trailer spring made my 29 CC Pickup "ride like a truck" - even more so than the original spring. It did solve an issue with the front driver's side wheel hitting the fender brace on that side.

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Old 03-10-2020, 10:28 PM   #5
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Default Re: 12 leaf front spring in 82A pickup

I measured several original front springs and this is what I came up with.


#1= 34" X .230" thick
#2= 32 1/8" X .220" thick
#3= 27 7/8" X .220" thick
#4= 24 1/8" X .220" thick
#5= 20 5/8" X .175" thick has holes for clamps
#6= 17 5/8" X .175" thick
#7= 15 1/8" X .175" thick
#8= 13 1/8" X .175" thick
#9= 11 1/4" X .175" thick
#10= 9 3/4" X .175" thick

The assembled spring is about 2" thick in the center.

The spring is 1 3/4" wide.
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Old 03-11-2020, 09:01 AM   #6
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Default Re: 12 leaf front spring in 82A pickup

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If they continued the thicknesses then the 12-leaf spring would likely be .350" thicker. Ford likely had engineering drawings of the front springs. Most information is about the 10-leaf units such as the Q&A on this site. https://mafca.com/tqa_c_frontend.html

Eaton Detroit lists the spring rates on their replacements as 343 for the 12-leaf unit and 315 for the 10-leaf unit. I have no idea where they came up with the dimensions for their replacements unless they were engineered from NOS parts. I'll have to look at the book "The Model A Ford - As Henry Built It" and see if there is any information about them in there. The green book only gives the leaf part numbers on the chart in there.
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Old 03-11-2020, 11:00 AM   #7
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Default Re: 12 leaf front spring in 82A pickup

One presumes Marco had access to the original Ford drawings when he made up his famed "spring chart."

One imagines a similar avenue was taken by A-Springs.com and perhaps others when they embarked on reproduction springs. Hard to claim "exact reproduction" without it.

As you say though - they were pretty simple. Almost simple enough to substitute a boat trailer spring and still have it work passably.

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Old 03-11-2020, 01:05 PM   #8
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Default Re: 12 leaf front spring in 82A pickup

This is a copy of my sub-post to this subject on the fordbarn last November"

Most (maybe all) spring manufacturers do not make the front spring to spec. Eaton Detroit Spring makes springs for most makes of cars. Years ago I talked to them and they had a copy of the original print. It called for three different thicknesses for the leaves. They make them with all leaves the same thickness. Eaton Detroit said the sales volume was too low for them to stock the minimum quantity of the three thicknesses.

A friend who was a Ford truck suspension engineering supervisor used Eaton Detroit for prototype springs. He was able to get them to make two front Model A springs to spec. They had to machine the steel they stocked to the "other" thicknesses. Needless to say the cost was exorbitant! He got one and I got the other. Load and rate vary a lot when not to spec. Most would likely not know it because something new is better than a fatigued existing one.
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Old 03-11-2020, 06:58 PM   #9
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Default Re: 12 leaf front spring in 82A pickup

Some history on this particular spring. My Dad bought the truck off a farm near Grand Forks, ND in 1960. I'm 100% sure he never changed it. So this narrows the opportunity to replace between 1930-1960. Not sure when I'll remove it to replace the hanger bushings, and when I do that I will get dimensions and pics to post. All mysteries get solved one clue at a time.
All the responses appreciated.
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Old 03-11-2020, 09:08 PM   #10
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Default Re: 12 leaf front spring in 82A pickup

I found the spring thickness info that Eaton Detroit told me several years ago. They said they had a copy of the original Ford blueprint.

Bottom leaf .180"
Next five leaves .176"
Top four leaves .204"

Their repro had all leaves .204" which had to give a very stiff ride compared to original.

Most people think a few thousandths of an inch in thickness would not make much difference. I was a quality control supervisor at a Ford manufacturing plant that made springs though coil not leaf. Size has the same effect so load and rate can differ greatly. Therefore, unless you want to pay for a custom-made spring, repros likely are going to have a harsher ride.
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Old 03-12-2020, 09:20 AM   #11
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Default Re: 12 leaf front spring in 82A pickup

The book "The Model A Ford As Henry Built It" has a grainy photo of the 12-leaf front spring. The top two leaves look thicker which leaves some credence to the previous post. It mentions that it was introduced as an option for 1930 thru 31 and was mainly aimed a commercial pickups to give a bit more load capability all the way around.

It would cost a good bit to have the spring leaves ground to specs but that would likely be the only way to go to get a decent reproduction. The book also mentions that the spring clips for 30 & 31 were the first to have the Ford script on them.
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Old 03-12-2020, 10:01 AM   #12
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Default Re: 12 leaf front spring in 82A pickup

Technically, it is possible to "measure" an existing worn front spring to get to the information on leaf thickness.

One wants to measure near the center bolt. Wear will occur between leaves and particularly near the ends, both on the tips and where they strike the next leaf in line.

Lengths won't change.

Hmm. I think I have an original spring disassembled upstairs - it has a broken leaf for which I have the replacement, but may be waiting to be measured?

Or maybe someone has the print? A lot of prints have escaped from the Benson Ford Archive. As long as one doesn't "reproduce" for sale, isn't the information now in the public domain/"fair use only?"

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Old 03-12-2020, 12:32 PM   #13
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Default Re: 12 leaf front spring in 82A pickup

Only the use of a manufacturer's name without permission would be a problem on restoration parts or documents. The patents ran out way back there but trade marks & copyrights last as long as they last.
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Old 03-12-2020, 01:02 PM   #14
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Default Re: 12 leaf front spring in 82A pickup

https://www.thehenryford.org/collect...parts-drawings

Quote:
What is the procedure for ordering copies of drawings?
There are two services that are offered. The first one is for customers who can visit us onsite in the reading room. The second option is for offsite orders, for those who are unable to visit the reading room.
Onsite: You can print out your own copies of parts drawings by using a microfiche reader/printer. The fee is $5 per microfiche. (This service is not available for offsite researchers).
Offsite: You must fill-out, sign, and return with payment, the following Parts Drawing Order Form. You must provide the part(s) drawing(s) number(s). If you do not know the engineering or factory part number, we will research the numbers for you at an additional cost of $35 per hour. For a detailed description of our research services, please see Services.
Fees: The fee is $30 per drawing.
Payments can be made with a credit card or check. If paying by check, make the check out to "The Henry Ford."
Copies are delivered as high resolution digital scans on CD.
Restrictions for Commercial Use

The Henry Ford is not part of the Ford Motor Company. We are a separate, nonprofit institution. We have the parts drawings in our collection, and we can supply copies, but we cannot confer the right to manufacture reproduction parts for sale – you would need to contact the Ford Motor Company for that. Their contact for restoration parts licensing is:
Patrick Mulligan
Director Licensing
Global Icons LLC
6 Parklane Blvd
Suite 605
Dearborn, MI 48126
Ph: 313-281-4395
Patrick.mulligan@globalicons.com
So "commercial use" is verboten without prior authorization. One expects this might imply a fee.

"Informational" use (well, some of us would prefer to use existing design data for our own quality assurance) appears variable depending on media, and how much effort they have to put into access/research.

IIRC, the Ford drawing system is based on "part number?"

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Old 03-12-2020, 05:50 PM   #15
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Default Re: 12 leaf front spring in 82A pickup

Folks pay a fee to purchase copies at the Benson Ford Research Center. They fee just covers cost as far as I know but they don't want folks selling copies. Selling anything with the Ford Motor Co name or logo on it would require a licencing fee just like they charge the reproduction parts folks if they want to put the Ford name or logo on it.

They list the charges on the web site for copies as you can see. If you do it yourself, it's not very expensive. If you wish to have them do it for you, it could get expensive depending on how many drawings a person requires.
https://www.thehenryford.org/collect...arts-drawings/

I'm sure that being a research center for historical documents makes it a lot like any other museum. Museums like to get donations to their cause. The better the donation, the better the services. There are several folks that frequent the different parts of the Ford Barn that have made trips to the Benson Ford for information research. Some of them have written books utilizing that information. They don't have a problem with that.

Last edited by rotorwrench; 03-12-2020 at 06:00 PM.
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