Leaf spring breakage

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Inspecting my spring leafs, I have some corrosion pits – not extreme. It is probably not enough to cause failure, but maybe. I am having new main leafs made to avoid worrying about having a failure that could cause loss of control, but it makes me wonder. I imagine not many actually inspect or replace their leaf springs – I have never worried about it on my 40+ year Chryslers (I still think of them as modern). Has anyone heard of an antique having an accident due to leaf spring failure? If one asks a spring manufacturer of course they say they need to be replaced even if they are just old. But how common amongst restorers is it to replace leaf springs?

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All proper restorations replace the springs. It can be very expensive. Many people re arch them. Be sure to replace the shackle pins.

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Ed, Are the springs replaced to keep the car at the proper height and alignment, or because there is a significant chance of breakage. If breakage is a problem, can it sometimes be catastrophic?

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I’ve had many vehicles That broke a leaf or two in a spring.

Even the main spring leaf will stay in place if the U-bolts holding the spring stack to the axle, and the series of clamps that keep the stack together are tight.

I even had a car that had the loop at the front of the spring break. This is where the rubber bushing goes and the bolt retains the front of the spring to the frame.. this was a mid ’60’s car, and the eye or loop broke because of a few too many ‘hole-shot’s’ and abusive driving.

But in all instances, the car drove normally. the weaker spring stack cause the car to sag and look odd, and the ’60’s car drove a bit odd. But there were no catastrophic events .

In most cases the broken spring was found months later, when I was under the car for another reason.

Greg L

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I have a 1912 Marmon that is original with a paint job. It has a

broken front spring. I drove it a short distance with it that way. It

handled normally. It took a mechanic to turn me on to the problem.

Unfortunately, the spring is tapered on the edges and will cost about

$300+ to have a new one constructed. I get physically ill thinking

about the cost to rebuild every leaf on that car!

If you drive with abandon like Ed, you would be well advised to have

new ones made.

Does anyone have advice on painting/prep and lubrication of springs?

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Many Pierce cars have tapered springs….. they are a real hassle and cost a fortune to replace. The last set I saw done were custom made and then had to be ground by hand for more than 30 hours plus the grinding stones. Do the math, it’s very expensive. John Cislak has been collecting a huge pile of springs over the years, and has singles as well as whole sets. They are very heavy to ship. He can probably help you out if you need almost any Pierce 8 or 12 spring.

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Has anyone seen a set of springs rusted and stuck so there is no flex in the springs. I saw this for the first time a few months ago, on a 100 point car. I didn’t pick it up, but another car guy caught it. Car still drove ok but was stiff.

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Speaking of springs, my ’29 is very original and I noticed that the springs are just about flat with no arch when at rest.

Should the springs have at least a little arch to them when supporting the weight of the vehicle?

Car drives and rides nice. Other PA owners have said the car rides nice but I know the rear shocks are weak.

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Thanks for the responses – interesting. Some of the background of my question. Springs are very highly stressed when just at rest, and can be very highly stressed when overloaded, hitting bumps, and also under heavy braking. They are theoretically very sensitive to surface corrosion that can cause pre-mature breakage from fatigue, however the original designers would have set a fairly conservative stress level to avoid failures. They wouldn’t have anticipated us still driving these things 70 years later after they sat around corroding. The main leaf for our solid front axle cars serves both to be a spring and to keep the axle in position. The secondary leaves pretty much just contribute to the spring action , but keep the overall stress level down on the whole assembly. In the extreme alarmist scenario, bouncing over Tioga pass with no guard rails, a main leaf breaking between the axle and fixed fwd bearing (on P-A)could cause the axle to shift back to the limit of the rear shackle, and cause a sudden turn. As indicated above, the friction of the clamps or spring covers might keep it from being sudden and catastrophic, but a bit of an unknown and variable. If the secondary leaves fail, they should mainly just cause the car to sag and have a cascading failure over time as the spring stress levels go up and cause successive leaves to fail. If the main leaf is in good shape, it could end up on the rubber snubber between the spring and frame. Years ago my ’36 Packard had bad corrosion and broken leaves, replacing the complete springs wasn’t optional. The elegant thickness tapers of Packard and P-A leaves wasn’t practical so I ended up with new springs that were 10% stiffer and left the car riding too high. Eaton Spring in Detroit does indicate they can taper the thickness, I don’t know to what extent. I have elected to replace the main leaves for peace of mind, and keep the original secondaries.

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Craig, on my ’31 phaeton the rear springs were almost flat, so when Bob D. asked me for a pattern, I gladly removed my rear springs and sent one to be replicated…including a set for me.

New springs and all the right bushings, and the springs are still very flat with little travel on the shackle. That said, the car rides nicely so no problem. With these fairly heavy cars, I believe that there’s little spring travel vertically…

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I don’t know much about springs. When John Cislak decided to make valve springs for the Pierce 8 and 12 cars, I saw the specification sheet for the “simple valve spring””. As I remember it was eight pages long in very small type with at least 75 specifications. I am sure the leaf springs have more going on than most people realize.

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Thanks for the reply, David.

Sometime soon I plan on pulling the spring shackles apart and go through them as you can hear a slight creak when you step up on the running boards.

I just wanted to know if I was going to have to hunt down some springs as well.

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Try Fort Wayne Spring 260-424-6263. This is a family owned business that started in about 1924. They kept all the records & specifications since they started. FW Spring has furnished me new front & rear tapered springs for my 1932 Pierce plus my L-29 Cord & 1930 Auburn. They have also suppied heat treated bumper back bars.Great to work with plus their prices are reasonable.

Dave

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A quick search of the PASB discs on leaf springs brings up LOTS of info. The springs are supposed to have a reverse camber when loaded. The PABS discs are HIGHLY recommended as a first stop for expert info. Pity you cannot read them in bed easily!!

Seasons Greetings

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jak.

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Jak,

You just need an iPad to read them in bed!

Peter

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Peter,

What’s an iPad? Does Dave Murray or John Cislak stock them? It’s

great to have a fearless leader with his ear to the ground. Do

you need a cigar to make them work properly? Have a Merry Christmas

to all!

Tony

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Ok you Guys

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I thought that the whirring noise from the iPad was too irritating to read in bed. NOT like a quiet smooth running Pierce-Arrow! Besides the image of our Fearless Leader with his eye on his iPad, his ear to the ground & his shoulder to the grindstone while having a Yuletide cigar sort of put me off the idea of bedtime iPad reading!! And to think this discussion started out about springs!! Cheers to y’all—-jak.

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Things do spin out of control at times, eh?

Merry Christmas to all and a Piercing New Year!

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The Pierce-Arrow isn’t the only thing stuck in the garage today!

Merry Christmas. James

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I did 65 miles in the roadster today with the top down! It was only 29 degrees but I managed to stay comfortable. Another frostbite tour over. My best, Ed

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