How many "leaves" should be in the rear spring?

[Pat Martone]

I have a 1931 Slant Fordor, and counted only 6 leaves in my rear spring, but from looking at suppliers' catalogs, the sedans should have 10 leaves.
(My front spring has 9 leaves.)
My rear end does not appear to be low, and my running boards are level and parallel to the ground.
Should the rear end of the car be a little higher than the front, with the running boards slightly at an angle - should I install a 10 leave rear spring?
(I have noticed that some Model A's have a higher rear end than the front - is that the way it is supposed to be?)
If I do change to a 10 leave spring, I don't think my 2 frame mounting "U" bolts are long enough; they are just barely long enough for my 6 leave spring.
Thanks in advance for your opinions.

[ctlikon0712]

Here, this should clear it up.

[Pat Martone]

To ctlikon0712,

Thank you for the chart, but unfortunately I cannot read it because it is blurry and too small. Is there any chance that you have a better scan that you can provide?

Thanks.

[Mitch//pa]

[Skibb]

My A when purchased last summer had six leaves in the rear spring also. I was told that the previous owner has put in a "coupe's" springs to save money. If you think of the eighty years of different owners with various perspectives on how to keep their Model A running, anything is possible. "Patrick" now has a ten leaf spring back there.

[d.j. moordigian]

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Try this.....it has the chart..........Marco's Spring Chart.........

[lindy williams]

Tudors, Fordors and pickups ans station wagons had 10 leaf rear springs. Coupes and phaetons had 8 leaves and roadsters had 7 leaves. I don't know about Vickys and A400's.

[ctlikon0712]

Sorry about that, I converted it to a PDF but I lost the color chart feature.

[QGolden]

Do you have them out to count them? The top two can be hard to see up inside the crossmember. If your "U" Bolts appear to be fully used, you might want to double check.

[Pat Martone]

QGolden,
Thanks for your comment.
The spring is installed, but I was able to count each leaf by feeling with my fingers, reaching inside of the cross member, and I counted 6 leaves, including the top one which appears to be only about 18 inches long.

[Pat Martone]

UPDATE: I am sorry, but I made a mistake - I found a photo of my rear spring out of the car, and it does, in fact have 10 leaves (not 6 leaves as I previously mentioned).
Now I am wondering why my car is sitting a bit lower (maybe 1"-2") than other Model A's I have seen, including the same model as mine (160B).
Could it be that it is a low quality spring or a "tired" spring?
I understand that some people can tell by looking at the shackles if the spring is not at full strength, so I am including a photo here for comment.
Does the shackle photo indicate the my spring is "OK"?
Thanks again for your thoughts.

[Joe K]

Originally Posted by Pat Martone

UPDATE:
Could it be that it is a low quality spring or a "tired" spring?
I understand that some people can tell by looking at the shackles if the spring is not at full strength, so I am including a photo here for comment.
Does the shackle photo indicate the my spring is "OK"?
Thanks again for your thoughts.

Yes and yes to either of the spring questions. We're talking upwards of 80 years on an original spring. And the repops that have been sold forever by Sears Roebuck, JC Whitney, Western Auto are NOT the quality that the original Model A springs were, either in engineering or materials.

Still, your shackle position appears "normal" to me. The wheel is on the ground and the car is not loaded? The shackle is on the "up" side of perpendicular to the spring leaf meaning it has some travel to perpendicular and beyond as the car is loaded.

Still, the eye to eye distance may not be the same as an original Ford spring - that quality issue again.

It is possible to "re-arch" springs and do it on your home workbench/vise. I've not done it though and I've heard the effect is less than permanent - sort of like the original spring set.

Joe K

[QGolden]

Hmm, my shackles are pretty much horizontal. BUT, my project is a new build and the frame is still supported on jackstands. I am sure someone who actually knows what they are talking about will chime in.

[Pat Martone]

QGolden and Joe K,
Thanks for the info.
A bit more background. My car came to me with no history due to a deceased owner, and it appears to be a car that was fully restored, perhaps 20 years ago. The spring appears to be new, and under the spring covers, it looks new with perfect paint and is relatively clean, except for the penophite oil that I have sprayed in between the leaves to reduce squeaking. I don't know if the spring is high-quality, like the show quality type I have seen on "a-springs.com". I do have a rear-mounted trunk which may add 30-40 lbs to the rear end, but I don't think that should reduce my rear end height by 1-2 inches. Again, because the rear end appears to be 1-2 inches lower than several other cars, I was wondering if replacing the spring with a known, high-quality spring, might raise the rear end height a bit.
Thanks again for the inputs.

[Joe K]

Originally Posted by Pat Martone

I was wondering if replacing the spring with a known, high-quality spring, might raise the rear end height a bit.
Thanks again for the inputs.

Unless you can come across an NOS or VERY good spring I might leave it as it is with what you have.

Most repop springs are made using ALL the same thickness of leaf material - and the thicknesses WON'T be as per the chart above. And this may be your clue to yours being an aftermarket spring. It has been my experience with a repop front spring that the replacement spring is a little "stiffer" than the original - but they do this for reason of eventual 'creep' of the spring downward with continued loading. Also marketing - every buyer wants to see a difference - SOME difference when they replace a part. And for springs it's very hard to engineer in a difference except in spring rate.

Another thing you might check is your shocks. One or both bound up on the rear can have the same effect. And binding up may be only "partial" (i.e. limiting travel.) This can happen as shock action by design is 60-40 (stronger one way than the other) but can be 50-50 depending on the shock rebuilder. As you drive the car with design action shocks, the shocks tend to pull the car "down" to the road (and improve handling.) But by definition this puts the shock active zone at one end of the travel: there may be a developed hang up at the other end of action.

Try disconnecting the shock links and see first if the arm action seems correct. (and check out that 60-40 action) Also measure if there is any difference in body height when disconnected.

I might conclude that if you're not rubbing your tires on the underside of the fender supports or hitting undercarriage parts against the frame or body, it's probably pretty close to design even with a repop spring. And there is some variability in spring action even with new original springs - they're just a hard thing to make and do it so they're consistent - you may have a weak one.

If you see a deal on a 10 leaf spring that you know to be an original you might give swapping it a try. Springs can be seen here at the classified for as little as $75. You'll spend more for the spring spreader to do the change safely.

Anyway, good luck and be safe. Exploring the differences and the reasons for them is all part of the fun of owning a Model A.

And every Model A is an "individual." I have not driven two Model As and had the SAME driving experience with each. Each has their own handle and feel.

Joe K

[Pat Martone]

Joe K,
Thanks for the detailed and informative reply.
I am wondering if the springs, made from "USA" SAE 5160 steel, for sale at "a-springs.com" are of a higher quality than some others. I am confused by an inconsistency between "a-springs.com" and Snyder's catalog which seem to have the same "Show Quality" USA-made spring with 5160 steel. I noticed on the a-springs.com website that they specify A-5560-D 10-leaf spring for the 160B model, which is inconsistent with Snyder's catalog which specifies the A-5560-A is for sedans, and Snyder's indicates the A-5560-D is for sedan deliveries and panel deliveries. (A-springs.com goes on to say that the A-5560-E is for the deliveries (where Snyder's says the A-5560-D is for deliveries)).
Perhaps the A-5560-D is more appropriate for the Slant Window (106B), and the Snyder's catalog is incorrect? I think I am suffering from analysis paralysis! (A typical problem with engineers.)

[Rock Hornbuckle]

Pat, do you like the feel of the ride? Is it too soft? Do you plan to have it heavily loaded? My '31 Fordor rear spring set arch is 1.2 inches low, but I like the stance and the ride, so I left it alone.

[Pat Martone]

Rock,
The ride is fine, but I have nothing to compare it to.
Yes, I have about 40 lbs of weight in the accessory trunk.
My Model A seems to sit 1-2 inches lower than several other cars I've seen.
My stance is about level but I would like my rear end a bit higher.

[1931 flamingo]

Pat: Are tires the same size on all the cars?? Personally I wouldn't worry about an inch. What happens if you've got a couple of people in the back seat?? Does it noticeably drop more?? Are you "bottoming" out over a bump or pot-hole??
Paul in CT
Tell the other guy his car sits too high and he has to make his like yours...........

[Rock Hornbuckle]

Originally Posted by 1931 flamingo

Pat: Are tires the same size on all the cars?? Personally I wouldn't worry about an inch. What happens if you've got a couple of people in the back seat?? Does it noticeably drop more?? Are you "bottoming" out over a bump or pot-hole??
Paul in CT
Tell the other guy his car sits too high and he has to make his like yours...........

Good advice! It is the lowest price option!