4Crawler Offroad Products - Custom Leaf Spring Shims

4Crawler Offroad Products

Custom Leaf Spring Shims, Blocks and Spacers

Designed and manufactured in the USA by Visual Diagnostics LLC

NOTE: Due to high order volume and supply chain issues, it may take some time for deliveries, production and shipments to catch up. Order backlog could be up to 12 weeks.

Contents:

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Introduction

Custom:(adjective) "Made or done to order for a particular customer" We make these parts to order since every pair of shims if likely a unique combination of length, width, angle, and mounting style.

If you've found this web page it's likely because some change has been made to your vehicle's suspension and now you're experiencing some issues with drive shaft vibration and/or steering. As such, realize you no longer have a stock vehicle, as a stock vehicle is usually set up properly from the factory. We don't know what has been done to modify your vehicle. As such, we don't go by "X model, Y year" vehicle, instead our parts are made to the dimensions you provide us as to the angle, length, width, etc. shims or blocks that you feel would fit on your vehicle. Also, realize that this isn't a simple matter of looking up a number in a table. For example, we once ran into an on-line shop that listed a 3" lift needed a 3° shim and a 6" lift neded a 6° shim. That seemed simple enough, the 3° shim was installed with a 3" lift and vibrations ensued. It turns out, removing that shim was the fix, so no shims were needed for that lift. And you'll also run across "experts" who'll tell you to "point the pinion at the transfer case" or similar "rule"without so much as looking at your vehicle. If it were that easy, this web site wouldn't exist, nor would it be so long and detailed. Our goal is for you to understand what the cause of your particular problem is and then understand how to go about fixing it.

On leaf-sprung vehicles, shims (or wedges) are often used to modify the angle between the spring perch on the axle and the leaf spring itself. The correction may be needed because of longer spring shackles tilting the pinion out of alignment, or to change from a single-cardan to a double-cardan drive shaft (for increased drive line angle capability), or to correct steering geometry (so your trucks handles better). An alternative to shims is to cut off the spring perches and re-weld new ones on at the corrected angle, but this is a lot of work and requires careful measurement to get things lined up properly.

Anyway, for whatever reason you need a shim, you do need one. And if you need one you probably need an exact angled one, not just the angle or two the shop has. When I needed shims, I found one shop that had 3° and 6°, and another that had 4° and 8°. All of these shims were aluminum, and not the nice strong billet aluminum, no they were cheap cast aluminum. Cast aluminum can be brittle, and it tends to fatigue or deform over time, and ultimately break. On the rear axle, this can be a pain if it happens on the trail, if it happens on the front axle, this can be downright dangerous.

Since I had only been able to find low quality cast alloy shims available and only in limited angles, I decided to make my own shims from a solid piece of mild steel, cut to the desired angle. Then a flat seat for the center bolt head is cut into the base to eliminate stress at that critical point. These shims are much more resistant to breakage than cast alloy shims. After locating a material source, developing the mfg. process, and forming a company to produce them, 4Crawler Offroad can now make these made-to-order shims available to others. If you want to "roll your own", click here for a VRML model of my shim design (5°). These shims are used to correct drive line and steering angles on leaf-sprung vehicles. Feel free to read my article on measuring drive line angles here before ordering. Finally, for permanent mounting, steel shims can easily be welded to the spring perch. No worries about shims breaking, twisting or falling out on the trail.

Lift blocks are similar to shims, except they are designed to add lift (to a spring over axle) or drop (to a spring under axle) and optionally may have a bevel cut in the top for pinion angle correction. Common aftermarket blocks use extruded aluminum sections. The thin wall material is prone to fatigue and cracking. 4Crawler Offroad can also make solid billet aluminum lift blocks with built-in angles. With the solid material, the blocks will hold up to the heaviest vehicles and loads.

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Custom Shims:

Below, you can see a few versions that 4Crawler Offroad has produced over the years:

Below are some examples of various shim styles, tapered blocks, relocation plates:

3 degree bolt-on steel shim 8 degree weld-on steel shim 2 degree shim, 3" wide Billet aluminum spacer/shim
A: 3° Bolt-On Shim
High accuracy shim pictured
B: 8° Weld-On Shim C: 2° Bolt On 3" (76 mm)
Wide
D: 10° tapered AL block w/ flat side pin
Shims w/ offset center bolt holes Spring Relocation Plates, 3/4", 1" Offsets 2.5" x 8" long shim Twin center pin Ford Shim
E: Offset Center Holes F: Spring Relocation Plates G: Extra long (2.5" x 8") shims H: Twin hole shim for
- Ford F150/Raptor model

Below is a closeup of some of the design details 4Crawler Offroad incorporates in the shims. First is the above mentioned center bolt head relief pocket. By creating a flat pocket for the head of the center bolt (on bolt-on shims) you prevent stress on the center bolt which could otherwise cause the head of the bolt to bend, as pictured in this photo. Also, each shim is stamped in 1 or 2 places with the angle it was cut to. This will come in handy down the road when you need to change angles for whatever reason. On several occasions, customers have run into trucks with existing shims (of unknown angle) where it is needed to add or subtract a few degrees. Without pulling the shim out, its very difficult to get an accurate angle off it. With the angle stamped into the end and the face, it should be visible in most situations.

Closeup of shim details Weld-on vs. Bolt-on shim
Closeup of shim details Weld-on vs. Bolt-on shim

In the image above-right, is pictured a weld-on and bolt-on shim with a spring center bolt in the middle. The weld-on shim has a center bolt hole large enough for the head of the center bolt to fit. The shim itself is designed to be welded to the spring perch, in effect becoming a permanent part of the perch. The bolt-on shim has a center bolt hole only large enough for the shaft of the center bolt to fix. The head of the center bolt then fits into the machined pocket in the shim and then engages the hole in the spring perch as normal. In this case, the shim becomes part of the spring pack.

Note the difference between the thin shims and the thick tapered blocks. In the shims, there is only a hole in the middle. In the blocks, there is a hole on one side and a pin on the other side. So, can shims be made with a hole/pin combination? Unless the center of the shim is thicker than 3/4" (19 mm) - 1" (25 mm), there is simply not enough room for a hole deep enough for the head of the center bolt (they can be up to 1/2" (12,5 mm) tall) and the pressed in pin, which needs to be 3/8" (10 mm) or so deep. Since all the "shims" are made under 1/2" (12.5 mm) thick, they can only be had in the through-hole design. If the hole/pin design is desired, then a tapered block will be required.

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Ordering:

NOTE: Due to high order volume and supply chain issues, it may take some time for deliveries, production and shipments to catch up. Order backlog could be up to 12 weeks.

All our shims and lift blocks are proudly designed and manufactured in the USA.

4Crawler Offroad can machine solid steel axle shims, custom angles, 1°-12°, made to your specifications:

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Standard 2" (50 mm) wide steel shims:

If you want a shim wider (or narrower) than 2" (50 mm), order the CUSTOM WIDTH shim.

For extra long or high angle shims (greater than 8°) or shims longer than 6" (152 mm), refer to this table

We have 3 options available for the standard 2" / 50mm wide shims:

Standard 2" shims:

Style:

Hole :

Hole Size:

Angle:

Length:

Quantity:

Style:

Hole :

Hole Size:

Angle:

Length:

Quantity:

US delivery International delivery


Use the buttons below to order high angle shims up to 1" (25 mm) longer than the length/angle limits listed above or for angles steeper than 12°:

Style:

Hole :

Hole Size:

Angle:

Length:

Quantity:

Style:

Hole :

Hole Size:

Angle:

Length:

Quantity:

US delivery International delivery


Use the buttons below to order extra long or high angle shims more than 1" (25 mm) longer than length/angle limits listed above or for lengths greater than 6" or for angles steeper than 12° or for shim thickness exceeding 1":

Style:

Hole :

Hole Size:

Angle:

Length:

Quantity:

Style:

Hole :

Hole Size:

Angle:

Length:

Quantity:

US delivery International delivery

Custom width steel shims:

Any width other than 2" (50 mm) wide, up to 3" (76 mm) wide and 6" (152 mm) long

Style:

Hole :

Hole Size:

Angle:

Length:

Width:

Quantity:

Style:

Hole :

Hole Size:

Angle:

Length:

Width:

Quantity:

US delivery International delivery


Use the buttons below to order a high angle shim up to 1" (25 mm) longer than length/angle limits listed above or for wider than 3" (76 mm up to 4" - 100 mm wide) or for angles steeper than 12°:

Style:

Hole :

Hole Size:

Angle:

Length:

Width:

Quantity:

Style:

Hole :

Hole Size:

Angle:

Length:

Width:

Quantity:

US delivery International delivery


Use the buttons below to order extra long and/or high angle shims more than 1" (25 mm) longer than length/angle limits listed above and/or for lengths greater than 6" (152 mm) and/or widths greater than 3" (76 mm) and/or for angles steeper than 12° or for shim thickness exceeding 1" (25 mm):

Style:

Hole :

Hole Size:

Angle:

Length:

Width:

Quantity:

Style:

Hole :

Hole Size:

Angle:

Length:

Width:

Quantity:

US delivery International delivery

Steel lift blocks (1/2", 3/4" and 1" tall, standard 2" width) in bolt-on or weld-on lift blocks.

  • Cost: $25.00/pair (pr. or 2 blocks) plus shipping and applicable sales tax.
  • Specify bolt-on or weld-on, length and height:
  • Style:

    Hole :

    Hole Size:

    Height:

    Quantity:

    Style:

    Hole :

    Hole Size:

    Height:

    Quantity:

    US delivery International delivery


    Pin Size:

    Length:

    Height:

    Quantity:

    Pin Size:

    Length:

    Height:

    Quantity:

    US delivery International delivery

    Steel lift blocks (1/2" and 1" tall, custom width) in bolt-on or weld-on lift blocks.

  • Cost: US$35.00/pair (pr. or 2 blocks) plus shipping and applicable sales tax.
  • Some international shipments may cost more due to weight.
  • Specify bolt-on or weld-on, length and width:
  • Style:

    Hole :

    Hole Size:

    Length:

    Width:

    Height:

    Quantity:

    Style:

    Hole :

    Hole Size:

    Length:

    Width:

    Height:

    Quantity:

    US delivery International delivery

    Pin Size:

    Length:

    Width:

    Quantity:

    Pin Size:

    Length:

    Width:

    Quantity:

    US delivery International delivery

    2" Wide Axle Relocation Plates (specify length in the Note field):

  • 2" wide, 3/8" thick
  • 5/8" locating pin and 5/8" holes offset 3/4" and 1" from center standard
  • Custom offsets (3/4" or more) and pin sizes available, specify in the order Note field
  • Default length is 4-3/4" long and available thicknesses of 3/8" or 1/2".
  • Custom lengths available, up to 6" long, specify in the order Note to Seller field
  • Cost: $25.00/pair (pr. or 2 plates) plus shipping and applicable sales tax.
  • Quantity:

    Quantity:

    US delivery International delivery

    And now available, low offset relocation places for those needing to relocate the axle less than 3/4". These plates will be 3/4" thick and allow center hole/pin offsets of 0" - 3/4". This is due to needing to have plate depth to drill a 5/8" center bolt hole 3/8" deep in one side of the plate (to accommodate the head of the existing center pin) and to seat the 5/8" center pin ~3/8" deep in the other side of the plate. Specify the offset of the single offset hole in the "Note to Seller" field of the order form.

    Quantity:

    Quantity:

    US delivery International delivery

    Custom Width Axle Relocation Plates:

  • Over 2" wide, 1/2" thick
  • 5/8" locating pin and 5/8" holes offset 3/4" and 1" from center standard
  • Custom offsets and pin sizes available, specify in the order Note to Seller field
  • Default length is 4-3/4" long
  • Custom lengths available, up to 6" long, specify in the order Note to Seller field
  • Cost: $40.00/pair (pr. or 2 plates) plus shipping and applicable sales tax.
  • Quantity:

    Quantity:

    US delivery International delivery

    Spring Perch Spacers:

    Style:

    Hole :

    Hole Size:

    Length:

    Quantity:

    Style:

    Hole :

    Hole Size:

    Length:

    Quantity:

    US delivery International delivery


    Style:

    Hole :

    Hole Size:

    Length:

    Width:

    Quantity:

    Style:

    Hole :

    Hole Size:

    Length:

    Width:

    Quantity:

    US delivery International delivery

    Longer center bolts:

    Typical center pin dimensions, may vary:

    Shank Dia Metric Bolt Length Unthreaded Thread Length Head Dia.
    5/16" 8mm 2.25" 1.0" 1.25" 0.46"
    5/16" 8mm 3.0" 1.6" 1.4" 0.46"
    3/8" 10mm 3.0" 1.6" 1.4" 0.55"
    3/8" 10mm 3.5" 1.8" 1.7" 0.55"
    3/8" 10mm 5.0" 1.0" 4.0" 0.56"
    7/16" 11mm 4.0" 2.5" 1.5" 0.65"
    1/2" 12.5mm 4.0" 2.1" 1.9" 0.74"

    The unthreaded shank length will be the difference of the bolt length and the thread length.

    Center Pin Ordering: sold in pairs (i.e. 2 bolts/nuts)

    Size:

    Quantity:

    Size:

    Quantity:

    Size:

    Quantity:

    Add a pair to a your shim order
    i.e. no added postage
    Order for US delivery,
    i.e. adds first class mail postaage
    Order for International delivery,
    i.e. adds international postage

    Toyota e-brake lever extensions: