For GFtE et al, Early Front Ends and Shock Absorbers

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Model T Ford Forum: Forum 2017: For GFtE et al, Early Front Ends and Shock Absorbers
Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Friday, September 15, 2017 - 05:26 am:

This began as a few comments on the "Sara inherited her grandfather's 1915 Touring" thread. Pictures showed the car with an early style of shock absorber known to create problems, so of course, I commented about them. John and Sara then clarified that the shocks had already been changed out at the suggestion of someone else that was helping to get her grandfather's T ready for the road again.
Gil F then asked about them as the '14 touring car he just got has them, but he is not familiar with those shocks himself. For those that do not know Gil F, he is a long time and very active horseless carriage and model T fellow. But nobody knows everything.
Rather than gum up John and Sara's thread, I decided to answer here.

Henry's model T was a marvel of engineering. Tough, light, extremely flexible, and very reliable by the standards of its day. It is well known, that part of that toughness was due to Ford's use of three point suspension of the major components of the chassis. The engine, rear axle, and front axle all mount to the frame in a three point way. But it goes beyond that. The rear spring attaches at three points, one to the frame, two (one at each end) to the rear axle. The rear axle attaches at the two ends of the rear spring, and the torque tube onto the rear of the engine. The engine attaches to the frame in three points (with a technically fourth point which is free-pivoting connecting to the rear end). The front axle also attaches to the two points at the ends of the front spring, with the third point being the wishbone ball under the engine.

All those three points become pyramid like structures. Each extremely strong, basically ridged, yet, connected to each other in a way that gives great flexibility to the entire chassis.

This all brings us to the point of this discussion, The front end, and what that style of shock absorbers do to it.
A little story, that should illustrate how strong one part of this combination is.
Many many years ago, when I was the young kid with an interest in history, several members of the local T club went over to another member's home, just to look over his progress. This fellow had been working on a T for awhile, and needed to move it from the garage on the side of his house, into the shop behind the house. They lived on a corner with side access around the side from where the garage was. The T was sitting in the driveway in front of the garage, and only about half together. Someone saw that there was no wishbone under the car, and suggested people push the car slowly to move it. The owner said "Naw, I've done this before." Jumped into the car, started the engine, and drove slowly down the driveway, across the gutter, out into the street down around the corner and back across another gutter and driveway on into the back yard and up to his shop. All the way with the front axle swinging and swaying and trying to flop around because there was NO wishbone! What that told me, and should help you to realize, is that the front spring and shackles alone hold the axle fairly well, at least at low speeds. Now, certainly, if one were to try that at real speeds, across potholes and speed bumps or rough terrain, it would definitely let you down hard (probably turning the front spring main leaf into a rather large corkscrew in the process). Still, even without the wishbone, the front axle, as Henry made it, is held rather well under the front of the frame.
Consider the axle suspension as Henry made it. Short stout perches, forged and shaped for strength to suspend the front half of the car on close, short shackles, to that spring that a car can be driven on a little bit even without additional bracing.
Now consider the shock absorbers in question. Instead of a short, stout, forged perch, it has a long convoluted stand, with a loose housing that has a spring inside. From that spring, another rod of several inches length hangs down to provide a mounting point for the shackles. Precise details vary from one set to another. Many are poorly made stands that have been known to break under stress. Some are parts riveted together, and basically, none used Ford high quality steel. Another factor that comes into play, is the fact that steel is not as hard and solid as we tend to think it is. All steel has a certain amount of flex. It will bend a little (you cannot even see it), and provided it is not bent too far, will spring back to its original shape. With Ford's "short stout perch", that bend is so small you probably could not even measure it without precision equipment. This is where math gets a little crazy. Exponential numbers. The exact figures vary greatly with various metals, sizes, etc. But basically, if you double the length of a given part/material, you quadruple the amount it will bend. The stand by itself is about four times (double double) the length of Henry's perch. Materials are different, but the estimated flexing is still about ten times how much Henry's perch will flex. The leverage involved also means that given the lesser quality steel used is very likely to break just above the axle.
From that potential disaster, we move to another. The little spring in the can supports the car. Not bad, just not robust and firm like Henry's perch. Again, different companies and production runs of similar shocks vary a lot in details. Most hang the car on a steel rod (about half inch) that runs from the top of the spring in the can clear down to the shackle connected to the main front spring. That silly rod is somewhere near six inches long. An average person could seriously bend that rod by using two large wrenches, and no vise.
Try driving that mess without the wishbone. It probably would fold flat at the first gutter, if it even made it that far.
Stability is extremely important for the safety of any model T driver or passenger. The front end, and steering must be fairly stable. The way the rod hangs from one spring to another, passing through a sloppy hole in the bottom of the upper spring's can? Simply cannot remain very stable. As parts wear, the amount of swing and sway allowed to the shackle gets more and greater. This adds to the potential for the front end to go into shimmies or worse, the dreaded "death wobble", where the front end tries to shake itself to pieces.

In short, the big problem is simply the expansion of Henry's tight little mounting for the front spring and shackles into a large convoluted circle of potential failures.

The reality is, one could have a set of these on a car for years. Drive it sparingly, local parades, moderate speeds. Be comfortable and feel safe. And one could likely go on a few major tours with no serious problems. The problem becomes that wear, and stresses over the years, tend to bend and fracture some of these parts on these type shocks. Often, some little thing triggers the disastrous failure. One fatal accident on a national tour a few years ago occurred at low speed, pulling off the road onto the shoulder, when some uneven ground folded the axle. Ken Meek's accident occurred when he lost a front tire at a fair speed. The resulting stress broke one of his shocks and flipped his car.

There have been extensive discussions about these over the years, both the shocks, and the few accidents.
A couple of thread links:

Both of these threads have long discussions, ramblings by me as well as others, and pictures of several variations of the shocks in question. Also more links to more threads.

It IS important to note, that these problems are mostly with this one type of after-market shock absorber.
Hasslers, Float-A-Ford, and H&D types do not have the problems inherent to these tall tower spring hangers. All of them (Hasslers etc) maintain a more compact and stable connection between the various front end components. Any springs are outside the circle of support, and act upon leverage to smooth out the bumps in the road. The potential failure points are more robust, and much less likely to fail. And if they did fail, less likely to let the front axle flip under the car.
Many model T owners have driven many thousands of miles on Hasslers and the H&D type. Accidents caused by them are so rare that I cannot even think of one.

Long enough for now. Good night, and be safe.

Top of pagePrevious messageNext messageBottom of page Link to this message  By Gilbert V. I. Fitzhugh on Friday, September 15, 2017 - 11:46 pm:

Many thanks, Wayne. I shall study this after I get back from the HCCA 1&2 in Virginia next week.

Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith, Lomita, California on Saturday, September 16, 2017 - 11:10 am:

What does GFtE mean?

Top of pagePrevious messageNext messageBottom of page Link to this message  By Gilbert V. I. Fitzhugh on Saturday, September 16, 2017 - 11:57 am:

On the HCCA website, I sign my posts Gil Fitzhugh the Elder, to distinguish myself from my son, who is also a member.

Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Saturday, September 16, 2017 - 04:36 pm:

Larry, Senior and junior are both well known and very active HCCA members, highly respected and good people. Gil the Elder has written many short articles for the "Gazette", he has been very active at both local and national levels. He is one of the so very many people in this hobby that we should all thank for their contributions to the hobby. As are you also, Larry. Thank you for the research you have done, the replacement parts you have provided, and the many other contributions you have made to our knowledge of model T history.
I sometimes respond to his posts on the HCCA forum, there I started that shorthand which follows his signature.

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