Leaf Spring Identification

[Sale] Click to see What's on Sale
Click for Understanding Leaf Spring failure [Help]
Many times it is simply a question of calling and asking for a replacement spring for a certain car, however at times, when ordering custom or antique car springs, more information may be required. These pages were placed here to aid in the specification of those springs.

Since there is always time to do the job right the second try, a little time spent in the identification of a spring the first time through, is time well spent. The enclosed information will guide you through the usual answers you will need to provide for us to identify the spring you are looking for. It may seem like an exercise in writers cramp but remember, we are only trying to provide you with the correct spring.

How Wide?

The first step in the identification of springs is the width, or how wide is the steel that the spring is made out of? Be careful of leaf springs that taper both in thickness and width. This fact is very important to communicate.

How Many Leafs?

Next we need to look at the center of the spring and count the number of pieces of steel, or leafs (hence the leaf spring name). It is very important to look at the center of the spring fore the bottom leaf may be very short and could be missed, so double check...

How Long?

Although I'm sure you would like your spring for a long time, if your spring is a custom design, or a racing or antique application, you may need to take a measurement of that spring. Although you may feel that you are entering uncharted territory, it is really quite easy. Let me demonstrate. A spring is manufactured in the flat position, I mean without any arch or shape and hence they are measured that same way. So in order to measure a leaf spring that has an arch or shape to it, you must measure along the curve. It is really pretty simple to first measure, from the center of the eye or mounting point to the center of the spring where there is a bolt, something called a center bolt. Pretty simple huh? This measurement is taken from each end so what you would end up with is a spring that would be lets say, 23" x 21".

Spring Steels

Although normal structural steel sizes are made in even fractions like 1/4", 3/8", & 5/16" of an inch, spring steels today do not. A spring steel which may look like 1/4 inch is actually .237 or .262. The correct tool to measure a spring steel is a micrometer. Now this may not be in the tool box of the typical homeowner, so a simple short cut may be in line here.
If your spring DOES NOT have liners installed between the leafs then AT THE CENTER you can measure the total thickness of the spring and divide by the number of leafs in the spring. Since not all springs have the same thickness all the way through the spring, this only give you the average thickness of the spring.

English Spring Steels

Many springs of English origin are made from a "non alloy" or "carbon" spring steel. Whenever possible, replacement springs will be made of same steel chemistry as the manufacturer intended, however in some cases, currently available spring steel may not closely replace the original size. In these cases, it may be necessary to design a custom spring which functionally replaces your spring but differs in the steel thickness and the number of leafs. We will closely communicate with you though, to keep you informed of your options and what tradeoffs you will have.

Restoration Level

How close to original do I want my spring to look?
Simple question but no simple answer. The reason we ask is we are able to manufacture a wide variety of leaf springs that functionally replace your leaf spring. If we originally made the leaf spring then the replacement spring will look like your original. Since that will probably not be the case, then a decision needs to be made how close to original you want your spring to look and how much you want to pay for it. In order to closely match the look of your original spring and it's tooling marks or identification, a replacement spring will be nearly completely hand made. This is well within our abilities, however time is money and we will be happy to quote you in advance as to what we feel your cost will be. Obviously if we are matching the look of your spring, we will need your spring to look at. We will be happy to return your spring to you whether or not you choose to buy, no obligation except for the freight.

What about Part Numbers?
Part Numbers may be difficult to match to currently available steel stamps in both type face and type size. Just ask, we will let you know after we look at it.

What about Logos?
Unfortunately, we cannot and will not mis-represent the product we make to be something that someone else has made. We will reuse components or leafs that may have a logo on them at your request, but we do not represent our springs to be made by someone else.

The Right Spring?

A lot of factors influence whether or not you are getting the right spring. The right spring in terms of it's correctness for the vehicle, the right spring in terms of quality and the right spring in terms of price.

Quality: Steel

It would seem that when you tell someone that you want a new spring, that you would get new steel in your new spring. When you compare different suppliers, and decide to order your new springs, be sure you are buying new steel. When you order a completely new spring from Benz Spring, you will only get new steel.

Quality: Manufacturing

Although there are a lot of things you can do with a cutting torch, spring manufacturing is not one of them. The springs you buy should be built to manufacturers specifications for design measurement, fit and heat treating where physically possible. The equipment used needs to be more than a sledge hammer, cutting torch and a paint brush. Look around the shop you choose to do business with, if you don't see a new steel, forming and heat treating equipment, then keep looking.

Quality: The Finish

Pride in one's product is evident in it's appearance and service level. Finish goes beyond paint and includes product support and professionalism.

Arching/Re-arching:

Hot or Cold?
First of all we need to get these two words clear. Arching a spring is putting the original shape into a leaf spring. Re-arching a spring is reshaping a previously manufactured leaf spring.

In normal spring making only hot arching is done. In this process, the heating stage relieves the stresses in the steel and allows the steel to be bent and take its new shape. The steel is then quenched or cooled rapidly, hardening it and the re-heated or drawn to achieve the desired hardness.

In re-arching, both hot and cold methods are used. In hot re-arching, the process is the same as with arching but old steel is being rather than new steel. In cold re-arching something entirely different is going on. A spring leaf is placed on a special anvil or special press and small kinks are placed in the leaf changing it's overall shape.

Does it make a Difference
YES, a common misnomer is that a spring needs to be re-arched. A spring when removed from a vehicle usually will conform back to it's original shape, even though the vehicle was lower then it was new.

What is going on is either the steel is fatigued or the vehicle is being subjected to increased loads. The spring has lost its ability to hold up the vehicle up under it's present load. This is a function of strength and not arch. The cure for this is increasing the load rating of a spring and that can only be done by replacing it with a heavier one or adding additional leafs. By adding additional leafs, the strength of the spring will change and with it the height of the vehicle, so now re-arching may be necessary.

[Home] Click to Return to Benz Spring Home Page
If you have any comments, please address or click here to: kbenz@benzspg.com
Benz Spring Co
700 S Forest St
Seattle WA 98134
206-624-7733