Pinion Alignment Shim Installation Tips

The stock bolt (shown on top) that holds the leaf-spring pack together is 3/8" diameter by 2" long with a 3/8"-24 thread. It has a head diameter of 9/16", and a head height of 5/16".

When installing axle alignment shims to adjust driveline angles, the original bolt may be too corroded to remove without breaking -- or a longer bolt may be necessary.

The 2° and 3° axle alignment shims from Stealth Conversions are about 1/4" thick at the center, and may require changing the original leaf spring bolt with a longer bolt. The Stealth Conversions Alignment shims come with a pair of 2-1/4" long socket head screws and hex nuts.

If the socket head bolt is too long and interferes with the lower shock plate, cut the bolt with a hack saw, or a grinder.

PINION ALIGNMENT SHIMS AND LOWERING BLOCKS

Several companies make pinion alignment shims. Most are made of cast aluminum or zinc, and are too narrow to cover the entire width of the 2-1/2" wide leaf spring used on the S-10.

When the 2" wide aluminum shims are installed on the cast or extruded lowering blocks, the shims (or the lowering blocks) will fail because only a small portion is supported by the hollow lowering blocks.

When the shims (or lowering blocks) break, the U-bolts can appear to loosen.

Stealth Conversions alignment shims are 2-1/2" wide, and made out of high-strength solid aluminum, which will not fail in service.

When the shims are used on the cast or extruded lowering blocks, the center hole of the shim must be drilled out to 9/16. Some of the cast and extruded lowering blocks, however, do not have a pin height that is tall enough to protrude through the pinion alignment shim.

Stealth Conversions' Unique Lowering Block Design

The Stealth Conversions lowering blocks are unique in that the top of the block is threaded. This allows the pinion alignment shim to attach to the lowering block, while leaving the full height of the cap screw for the rear-axle locating hole.