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How To Remove K-Member & Front Suspension - K-Frame TeardownPart One-Teardown: What You Need To Know From the February, 2001 issue of Mopar Muscle By Steve Dulcich Photography by Steve Dulcich
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Face it, if like-new or maybe even better-than-new performance is what you want from your Mopar's suspension, it will likely need a comprehensive rebuild. Under normal use, the stock Mopar front suspension lasts about 100,000 miles. The fact is, even with fewer miles under hard use or over a long period of time, things can get mushy; and, unfortunately, the required chassis lube-job has become an almost-forgotten routine. The Mopar torsion-bar suspension was perhaps the finest front-suspension design of the period because of Chrysler's innovative and efficient torsion-bar springing and unequal-length control arms. The system featured torsion bars hex-anchored to a ridged mid-chassis-mounted crossmember and keyed to the lower control arm by an adjustable mounting socket. In turn the lower control arm is secured to the solid K-member via a rubber-bushed pivot shaft. The lower control arm is triangulated to the K-member by a forward-facing strut rod that forms the second leg of the lower A-arm. The strut rod solidly transfers the fore and aft forces of the front suspension during braking, acceleration, and cornering. The upper A-arm is formed like a conventional wishbone, pivoting on two inner bushings. The spindle mounts between the upper and lower control arms via two large spherical ball joints. This '70 Swinger 340, now... This '70 Swinger 340, now a rolling chassis, will get a better-than-new front suspension. Most trouble begins with the ball joints. It's internally supported by low-friction nylon inserts that require routine lubrication. After the factory lube, the grease fittings were snapped, requiring the fitting of new zerks for service lubrication. All too often the service lube never happened, resulting in worn-out ball joints. The same situation occurs with many ball-jointed tie-rod ends. Next we have the bushings. The most critical bushing in the system is in the lower control arm. The pivot shaft is rigidly mounted to the K-member, and the torsion-bar socket at the other end pivots with the lower control arm. This disparity in motion is wholly absorbed through the twisting rubber in the lower control-arm's pivot-shaft bushing. Eventually the twisting takes its toll and the bushing fails. Then we have the strut rod, rigidly mounted to the lower control arm but bushed at the forward K-member mount to allow for articulation through the suspension's motion. The forces on the strut bushings are primarily fore and aft, and whenworn, they cause the lower control arm to shift forward and back at the ball-joint end, making the suspension unstable. Up top, the rubber upper control-arm bushings are subject to normal wear, and they too eventually blow out. Bed rest doesn't do the suspension any good; the only cure is a rebuild. The best approach is to blow it all apart and replace everything, using an aftermarket rebuild kit. This '70 Dart Swinger 340 is in the process of a full rebuild, and a fresh front suspension is on the list. While rebuilding the front suspension piecemeal on the car is the norm for service, in a resto, pull the entire works from the chassis in one hit. The bulk of the suspension and steering system is mounted to the K-member, allowing removal as a unit by dropping the "K." Though rebuilding the suspension in the car while lying on the cold concrete can be some seriously dirty penance, with the K-member out the job is nothing short of enjoyable. A number of tricks we've developed over the years make the job easier. This month, we'll cover the removal of the complete K-member and front suspension from the car, and weld-up a rig that allows us to mount the K-member to an engine stand for service. We'll show what it takes to break it all down and pass on the hard-learned tricks of the game.  The key player up front is...  The key player up front is the K-member, bolted to the front chassis rails by four large bolts; it carries the engine, steering, and front suspension systems. The engine is already clear. Dropping the K-member now will relieve the body of its front suspension and steering.  With the chassis up high on...  With the chassis up high on heavy duty jackstands for clearance, unload the front torsion bars. Just unwind the adjusters at the lower control arm.  Everything that links the...  Everything that links the body to the "K" has to be unhooked, including the shocks' upper mounts and the steering-column connection at the box..  Removing the torsion bars...  Removing the torsion bars is usually the toughest part of the job, but here's an easy way: Remove the rear retaining clip as usual from the rear anchor, and then take the nut off the pivot shaft where it goes through the K-member (A). Next take the front nut and bushing off the strut rod (B) where it goes through the "K." Now the entire lower control arm can be levered back, which will push the torsion bar out of the rear anchor. The bar can usually be pulled out of the lower control-arm socket by hand. If it's stuck, separate it with a few hammer taps on the torsion-bar socket of the lower control arm.  Disconnect the upper A-arms...  Disconnect the upper A-arms from the body by removing the pivot/adjuster bolts. Lever the arms up and out with a crowbar or large screwdriver. On swaybar-equipped cars, the bar prevents the suspension from swinging too far down. On non-swaybar cars, wire the lower control arm to the "K." Don't forget the brake-hose connection to the body.  With everything free, support...  With everything free, support the K-member with a jack (make sure it's secure, preferably strapped), and unwind the four bolts that attach the "K" to the rails. It's a heavy unit, so keep clear from underneath while unbolting.  With the frame in place, the...  With the frame in place, the suspension assembly bolts to the stand for easy access and a comfortable working height. The heavy hooks linking the strut rods to the frame keep the suspension from drooping.  Lowered, off, and out, it's...  Lowered, off, and out, it's time for a tear-down and rebuild. The strut rods are wired to the K-member to keep the suspension up, preventing the brakes from dragging on the floor.  Mopar Muscle's Steve Dulcich...  Mopar Muscle's Steve Dulcich invented and fabricated this frame that allows us to mount the K-member to the engine stand. The angle iron "outriggers" bolt to the four K-member mounting points, and the tall, flat steel plate at the back mounts to the engine stand.  Disassembly begins with the...  Disassembly begins with the brakes. Remove the calipers at their mounts, then the discs and dust shields.  Next, remove the steering...  Next, remove the steering linkage. We used a puller to break loose the tight tapered fit of the rod ends, but a pickle fork and hammer work too.  The control arms and spindles...  The control arms and spindles can be removed as a unit by unbolting the strut rod and removing the pivot shaft nut (arrow A). Here we can see the hook that holds the suspension up (arrow B).  You might need to tap the...  You might need to tap the end of the strut with a lead mallet to release the tapered seat in the lower control arm. Then the parts can be removed and separated on the bench.  Unbolt the steering box and...  Unbolt the steering box and idler arm, and the K-member is picked clean.  Mount the control arm assembly...  Mount the control arm assembly in a vice and unbolt the lower ball joint from the lower control arm, separating it from the spindle/upper A-arm assembly.  To break loose the ball joints...  To break loose the ball joints at their tapered seats, a pickle fork wedges them apart.  We've heard that ball joints...  We've heard that ball joints should be pressed out. The ball joints actually screw into the upper A-arm and removal requires a special square-drive socket and lots of torque. We had the special socket for the larger B-, E-, and late A-Body ball joint, but had to make one for the small A-Body piece. Starting with heavy wall pipe, the drive flats were arc-welded in, precision cut to size, case hardened, and quenched. Heat the A-arm frequently with a torch around the ball joint and then lightly oil to break the joint loose-ours required that treatment.  The upper control-arm bushings...  The upper control-arm bushings are best removed using a jackscrew, not a press. Use 11/42-inch threaded rod with a drive nut welded to one end. Place a socket on one end to drive the bushing out, and use a heavy tube or pipe fitting to receive the bushing at the other end. Make sure the receiving fitting sits flush with the control-arm contours; ours is ground to rest on the edge of the lip at the bottom of the A-arm.  The rubber and outer steel...  The rubber and outer steel shell of the original bushing remains in the lower control arm. Inexplicably, the typical advice is to heat the shell with a torch to release the rubber's bond with the outer shell. In fact, the rubber isn't vulcanized or bonded to the shell, and can be pried out of the arm cold with a screwdriver. Again, with poly bushings, the outer shell remains, but OE-type bushings require removal-a brutal job that requires splitting the shell along its length and prying it out.  The lower control arm only...  The lower control arm only needs the pivot shaft removed from the inner bushing. We used a press and pushed out the pivot shaft from through the torsion-bar socket. A heavy hammer in a vice will probably work as well. The control-arm bushing consists of an inner and outer steel shell with rubber in between. The inner steel shell comes out still attached to the pivot shaft. When using OE-style rubber bushings, remove the shell from the shaft by staking it along its length. We're using poly bushings, so the shell remains in place.  Now we send the fully torn-down...  Now we send the fully torn-down suspension and K-member for stripping. When it comes back, we'll paint and replate for the coming resto-detailing.  We'll reassemble the refinished...  We'll reassemble the refinished components on the stand and add new components complements of a PST rebuild kit. Rather than going purist original, we opted for PST's Polygraphite bushings and a set of KYB gas shocks to add nimble corner-turning performance to our straight-line stormer.
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