Shackle and Anchor Bolt Replacement
(Steel Bushing Type Shackles)
By Stephen Kassis
Leaf spring shackles are subject to extreme wear. Worn shackles can contribute to steering problems and, if severely worn, can be downright dangerous. Inspecting and lubricating shackles and spring bolts is just good periodic maintenance. There are two types of spring shackles – steel bushing type and rubber bushing type. Rubber bushing shackles are only used on passenger cars, while steel bushings were used in both car and truck. Procedures for installing rubber bushing shackles do not require special tools or procedures, so this discussion will focus on steel bushing shackles. However, the jacking and safety instructions are the same, no matter which type you have.
Steel bushing wear is increased when greasing of the chassis components is not done regularly. To remove the steel bushing shackles a good set of heavy duty jack stands (4-point) will be required. Block the wheels (to prevent movement front or back) on the opposite end of the vehicle from where you will be working. Using a floor jack, lift up the car and place a jack stand under the frame on each side. Wheels and tires do not need to be off the ground for this procedure but pressure needs to be off of the spring.
CAUTION: Make sure the stands are properly installed and secure before proceeding. Support the shackle end of the leaf spring with a floor jack. Adjust the jack to remove the spring pressure and allow the shackle to be disassembled safely. Work on one side at a time. Remove the center bolt and side plates of the shackle. Early and late shackle assemblies are different in design. Replacement procedures are different so separate installation instructions follow:
Early Design Shackles 1930-1933 All, 1934-35 Standard)
Early design shackles have smooth tapered pins pressed into the frame and spring eye. The pins will require a Porta-Power or hydraulic press for removal & installation. Do not attempt to hammer these pins as it may result in damage to them, the frame or the frame brackets. Hydraulic pressure or a specialty puller/installer will be needed to do this job properly.
Press in the new tapered pins into the frame and the shackle end of the spring. Press in new bushings into the frame anchor end of the springs. Note: bushings and pins must fit tightly in the spring and frame or something is wrong. Grease the bushings & shackle side plates in preparation for assembly. Install the bolt & nut at the frame anchor end. Reassemble the shackle side plates, center bolt and large spring washer. As you are tightening the center bolt get it snug so all play is out of the side plates. Over-tightening can cause premature failure of the shackle or bend the side plates.
There is a lock plate that holds the tensioning nut in place after it is adjusted properly. Slide the lock plate over the large nut and bend the two tabs over the side plates to lock in place. This prevents the nut from loosening in normal operations. After finishing assembly and before the chassis is back on the ground, grease all components with a grease gun and good quality chassis grease.
Late Design Shackles (1934-35 Master and newer models)
Late design shackles have threaded bushings pressed into the frame and the shackle end of the spring. The bushings will require a Porta-Power or hydraulic press for removal & installation. Do not attempt to hammer these pins as it may result in damage to them, the frame or the frame bracket. Hydraulic pressure or a specialty puller/installer will be needed to do this job properly.
A threaded bushing type shackle was used for 1934-35 Master models and all newer models. Note: do not attempt to press out the threaded bushings with the tapered pins in place. Remove the threaded pins prior to pressing the bushings out. If you have the bushing type shackle you can press out the old bushing while pushing in the new bushing. Go slowly and make sure that the bushings are properly aligned.
Lubricate and thread the new shackle pins into the new bushings. Cork seals were original for threaded steel bushings, however, neoprene replacement seals are available and do a much better job for less cost. Put new neoprene or cork seals onto each end of both pins. Assemble the side plates onto the pins and install the center bolt, lock washers & nuts to hold the side plates together. Tighten the center bolt securely. Strike each end of the shackle with a sharp blow from a brass hammer to be sure the tapers are seated. Check and re-tighten the center bolt of the shackle if needed.
Install all grease fittings and grease the shackles while there is no pressure on the pins. This will allow grease to flow all the way through the bushing.
Jack up the frame and remove the jack stands. Lower the vehicle onto the newly installed shackles. Check that the vehicle is sitting level. An out of level vehicle can indicate a bound up shackle or a worn spring.