Spring Identification

SpringIdentification

Three Ways to Identify a Leaf Spring

The following information details the three ways in which a leaf spring may be identified for a specific application. Thesemethods are listed in order of difficulty, therefore always attempt to identify by O.E.M. part number first before usingidentification by model or spring dimensions. In many cases the spring may be identified without the need for anymeasurements.

Identification by O.E.M part number:

How can the O.E.M part number be obtained? Use one of the following methods:

1. Call the local dealer with the vehicle serial number2. Truck-build sheet (line setting sheet) will often list the front or rear spring3. Check the spring for a stamping number as follows:

Full Taper Springs: Part numbers may be found in one of these locations: (see illustrations below)A. On the end of the last leafB. At the end of the wrapperC. On the side, bottom or top of the clip

Multi Leaf Springs: Part numbers may be found in one of these locations:C. On the side, bottom or top of the clip (most common)D. On the end of the shortest leafE. On bottom of the last leaf beside the center bolt (sometimes this is hidden until the spring is removed)

Three Leaf Trailer Springs:F. On the outside of the hook

Catalog 215

Sprin

gId

entif

icat

ion

Identification by O.E.M part number: (continued)

In many cases, the number stampings may contain only apart of the O.E.M part number.

Usually, Ford only stamps the prefix and the suffix and the basemust be added to complete the part number.

Example: Adding the 5310 base number to the F3HT prefix and JAsuffix completes the Ford Part number of F3HT5310JA whichinterchanges to the SRI part number 43-434.(Note: Other Ford OE part numbers could interchange with SRI 43-434).

With the part number, the spring can be found in the Part Number Interchange (Catalog 210) oron the Dayton Parts website at www.daytonparts.com

Identification by vehicle make, model and year:Where can the make, model and year be found?

1. Ask the customer2. The truck-build sheet (line setting sheet)3. On the vehicle's cab plaque (See Example)4. Model may be displayed on the vehicle5. Use catalog art work to determine the make & model

Identification (for example see page 541 for allKenworth models)

*Always try to identify at least the make and model before attempting to use this catalog. Once the make andmodel is known, use the catalog's “Chapter, Index” to find the catalog pages where the correct springs arelocated.

*When identifying the spring for a tandem axle truck or trailer application, make sure the suspension make andmodel are determined first. See page 8 for more details.

Identification by spring dimensions:This is by far the most difficult way to identify a spring andshould only be used if the first two methods detailed aboveare unsuccessful.

What are the important measurements?

1. Main Leaf Length:

a. Eye to Eye - Measured from the center bolt to the center of the eye in both directions along the arch.

b. Eye to Slipper - Measured from the center bolt to the center of the eye and to the end where there is noeye along the arch.

c. Slipper to Slipper - Measured from the center bolt to the end in both directions along the arch.

d. Camel Back (used on Mack only) - Measured from the center bolt to the end of the main leaf in bothdirections along the arch.

e. Single Point (5" wide springs used on heavy duty trailers) - Measured from the center bolt to the end ofthe main leaf in both directions along the arch. End hole size and distance from the center bolt must bechecked.

Spring Identification Catalog 215

SpringIdentification

2. Spring Width:a. Measured at the center bolt from side to side across the leaf.

3. Pack Thickness:a. Measured at the center bolt down the side of the spring

including all leaves, tow eyes, shock eyes and pads.Do not include any cast wedges or brackets.

4. Spring Arch: (always measure to the top of the main leaf, do not include any pads or spacers.)

a. Eye to Eye - Use a straight edge to mark the center of the eyes and measure the arch at the center bolt.b. Eye to Slipper - Use a straight edge to mark the center of the eye and the top of the slipper and measure the

arch at the center bolt.c. Slipper to Slipper - Use a straight edge on the top of the slipper ends and measure the arch directly over the

center bolt.d. Camel Back and Single Point - Use a straight edge to mark the top of the main leaf in both directions and

measure the arch at the center bolt.

Spring eye information:

1. No Eyes:Typically no eyes are used on helper, trailer and rear single axle springs.

2. Eye Types:Standard (Std) or Straight Eye with or without bushingBerlin (Ber) Eye with or without bushingReverse (Rev) Eye with or without bushings (common on Dodge)

5. Eye Leaf Length: (radius leaf springs only)a. Measured from the center of the eye to the center bolt.

Spring IdentificationCatalog 215

Sprin

gId

entif

icat

ion

Spring eye information:

3. Bushings:

a. HB or Harris bushings (2 piece rubber bushing used in automotive and light duty applications). HB bushings arenot considered part of the spring and must be ordered separately. Catalog lists spring eye type and insidediameter. (Example: Std/ ⁷⁄₈")

b. RB or Rubber Encased bushings (metal encased rubber bushing used on most automotive, light, medium andsome heavy duty applications). Catalog lists spring eye type and bushing part number. (Example: Ber/RB-159)

c. TB or Threaded bushings (metal bushing with a threaded interior used on many old automotive, light, medium-dutyapplications but more widely used on heavy duty applications). Catalog lists spring eye type and bushing partnumber. (Example: Std/TB-68)

d. Bronze or Bimetal bushings (greasable bushing using spring pins with grease fittings). Catalog lists spring eyetype and bushing part number. (Example: Std/RNK)

Explanation of bronze and bimetal bushing part numbers:

First (1st) character: Outside Diameter (OD)Second (2nd) character: Inside Diameter (ID)Third (3rd) character: Length

Characters stand for certain sizes as listed below:

Even with complete measurements it can still be difficult to track down the correct spring unless themake and model of the vehicle are known. Always try to obtain the make and model before beginningthe search. If make and model cannot be determined, use Dayton Parts’ exclusive Spring Finder(pages 13-44) to assist in make and model identification.

Spring Identification Catalog 215

SpringIdentification

Spring Identification

Spring Ratings and Capacities:

Spring Ratings:Springs are rated in several different ways throughout this catalog. A basic understanding of eachand how they relate to the ratings of other components in a suspension are shown below.

Axle Capacity: Axles are rated several ways. The rating which is most important when discussingsprings is GAWR (Gross Axle Weight Rating). This is the maximum allowable loadwhich the manufacturer approves to be carried by that axle. Axle capacity ismeasured at the ground and means the weight which a scale would read whenplaced under the tires.

Sprung Weight: This is the weight of the vehicle that is supported by the springs themselves. Thisincludes the weight of the truck “above” the axles plus the weight of the driver, fueland any cargo.

Unsprung Weight: This is the weight not supported by the springs. It includes the axle(s), brakes,wheels, tires and a portion of the steering components in the case of front axles.

Spring Capacities:Published Spring Capacities (or ratings) may be given for either the sprung weight (at pad) or atthe ground (sprung plus unsprung weight).

At Pad: The manufacturer’s maximum load rating of one spring as measured at the springmounting pad on the axle. This is the capacity that the spring itself is designed tosupport. The balance of the weight is supported directly by the wheels and tires andis not seen by the springs.

At Ground: This rating includes the At Pad capacity plus a portion of the unsprung weight. Insingle axle applications, it equals the At Pad capacity plus one-half (1/2) of theweight of the entire axle assembly.

Example: Part Number 62-830Spring Capacity At Pad 5,400 lbs.

+ 1/2 Axle Assembly Weight +600 lbs.= Spring Capacity At Ground = 6,000 lbs. (12,000 lb. Axle)

Common Spring and Suspension Capacities:

Front Axle Rear Single Axle Rear Tandem 4 Spring

Spring CapacityAt Pad

Suspension CapacityAt Ground

3,150 7,0003,550 8,0003,800 8,5004,050 9,0004,500 10,0004,850 10,8005,400 12,0006,000 13,2006,300 14,0006,500 14,6007,200 16,0008,200 18,0009,200 20,000

10,100 22,00010,600 23,000

Spring CapacityAt Pad

Suspension CapacityAt Ground

6,750 15,0007,500 17,0008,000 18,0008,500 19,0008,900 20,0009,400 21,000

10,400 23,00012,000 26,00013,000 28,00014,000 31,000

Spring CapacityAt Pad

Suspension CapacityAt Ground

7,500 34,0008,000 36,0008,500 38,0009,000 40,000

10,000 44,00010,500 46,000

Catalog 215