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Tubular Front Suspension Install - So Easy Even A Kid Can Do ItInstalling CAP Auto Products Tubular Front Suspensions From the October, 2011 issue of Mopar Muscle By Dale Amy Photography by By The Author
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If there is one modification to a Mopar that draws a lot of attention with readers, it's the addition of a tubular K-frame. Love it or hate it, the swapping of a tubular K-frame in a muscle Mopar is a swap that will be around for quite some time. By swapping the K-frame, the car owner can now-very easily-install rack-and-pinion steering, eliminate the torsion bars, thereby gaining header clearance, and even make a later model engine a bolt in. Yep, a tubular K-frame upgrade can yield a lot of benefits. But, how easy are they to install? When we found out that Jefferson High School in Monroe, Michigan, has a '71 Demon that serves as both educational tool and competitive drag racer, and that they wanted to install a tubular k-frame, we decided to follow along on the install and see how easy it really is. The K-frame they chose to install is from CAP Auto Products. The CAP tubular front suspensions are light, strong, and take up a ton less space than their factory counterparts. This one sports both coilover shocks and a rack-and-pinion steering system, but they also have versions available that still incorporate OEM steering and torsion bars. The guys at CAP designed their kit to bolt directly in place of your heavy and bulky factory hardware, shedding nose weight, and improving suspension response. A tubular K-frame also provides tons of additional oil pan and header clearance. CAP's K-frame can be ordered to accommodate small or big-block engines, including the new 5.7 or 6.1 Hemi. CAP's kits are said to permit the highest amount of suspension travel on the market, and are unique in their retention of both factory motor mounts and steering geometry. The seamless, cold-drawn tubular hardware is jig machined and welded, then E-coated, inside and out, prior to powdercoating (in a variety of colors), and kits are shipped fully assembled. Perhaps the best part is that CAP's strong, light tubular components are easy to install either individually by interchanging with OEM stamped components, or as complete spindle-to-spindle assemblies. How easy? Let's find out. The Jefferson High School... The Jefferson High School Drag Team. The one on wheels is a ’71 Demon, now running an aluminum-headed 360, race-prepped 904 TorqueFlite with a 3,500-stall converter, and 4.88 gears and a spool in the rear. It’s capable of 10.90s at around 120 mph. From left to right are: Zack Perry, Mike Brancheau, Jason Lingar, Mike McLaughlin, and instructors, Rob Eppler and Bob Williams. School Wasn't Like This When I Was a Kid
The "kids" shown feverishly laboring on the Demon are enrolled in Jefferson High School's Drag Team, a strictly voluntary, after-class, one-evening-a-week program in which students go beyond normal auto shop curriculum to learn the finer points of race car preparation, maintenance, and competition. Running since 1982, the program requires good scholastic grades before applicants can enroll. Under the also-voluntary supervision of auto shop instructor, Rob Eppler, and Bob Williams (Rob's counterpart from the school's fabrication/auto body shop), the Drag Team's high-performance curriculum might include such tasks as rebuilding the Dodge's small-block, transmission or rear end, rewiring, roll-cage fabrication, or whatever else is necessary to keep the quarter-miler healthy and competitive. Perhaps better yet, when the Michigan snow finally melts each spring, they pack up and accompany the Demon out to nearby Milan Dragway and campaign the Demon in the "High School Nationals" series, where it has been extremely competitive, year after year. The students not only wrench on the Dodge; each season, one amongst them is designated to don the helmet and do the bulk of the driving (everyone gets a chance to make some passes during test and tune sessions.) Sounds like a graduate course for gearheads.  1 Unless otherwise requested,...  1 Unless otherwise requested, CAP Auto Products’ tubular front suspension kits are shipped completely pre-assembled in a sturdy crate, and are available in a variety of powdercoated colors. Our subject kit has the optional steering rack as well as the no-cost option of tow hooks welded onto the k-member (though it is not optioned with the sway bar tabs that might well be desirable for street use.) No upper control arms are shown in this kit, as they were already installed on our Demon, and this kit’s lower arms are coilover-specific. Normally, a full rack-and-pinion-equipped kit like this (known by CAP as the “K Rack”) would also come with modified spindles installed, given that the rack changes the car from a rear-steer to front-steer setup.  2 The school’s Demon is also...  2 The school’s Demon is also swapping to CAP’s optional coilover shocks (sourced, as you can see, from QA1), but the k-member kits can also be configured with lower control arms that will allow re-use of factory torsion bars. Note that the kits are fully modular in design, meaning you can stick with your torsion bars for now, and then swap to a coilover setup later on, by substituting new lower arms. Also note that opting for coilovers will require welding in some support bracketry (as we’ll show you) but the rest of the kit is strictly a bolt-in proposition.  3 CAP’s design and hardware...  3 CAP’s design and hardware permits caster adjustment of three to seven degrees, as well as excellent bumpsteer geometry.  4 Jefferson High School’s...  4 Jefferson High School’s ’71 Demon is purely a drag car, and already wore CAP’s tubular upper control arms, as seen in this “before” shot. Its brakes will be re-used, so the calipers were subsequently unbolted and simply hung aside. The spindles were then removed and modified by CAP as documented in upcoming photos. We did the suspension swap in the school’s auto shop, which had hoists, but it certainly could be accomplished on the ground with some jacks, tall jackstands, and a couple friends’ help.  5 There are two possible...  5 There are two possible approaches to disassembly/removal of the factory suspension hardware. The first option is to strip off outboard or unsprung gear such as the rotors, spindle and lower control arms, as well as the steering linkage, before removing the K-member itself. The second is to detach as little as possible and simply remove it all as one complete assembly with the K-member. Option two is quicker but somewhat heavier, and is the method documented by CAP in their kit instructions.  6 Either way, the torsion...  6 Either way, the torsion bars will first have to be loosened and slid back out of the lower control arms. For the swap to coilovers, the Demon’s torsion bars were removed altogether.  7 Because it was intertwined...  7 Because it was intertwined within the primaries of the Demon’s long-tube headers, the guys had to separately unbolt and remove the factory steering linkage. Otherwise, the linkage could have been left attached to, and simply unbolted with, the k-member. Of course, with the new rack and pinion setup, all this OEM linkage goes on the surplus pile.  8 If you’re leaving the engine...  8 If you’re leaving the engine in the car during the swap, it must be supported prior to loosening and removing the factory K-member. You might think that such a support under the oil pan would be very much in the way, but the K-member gets removed in a slightly forward direction.  9 Two beefy bolts (arrows)...  9 Two beefy bolts (arrows) attach the K-member to each side of unibody/subframe. Plan on having an equally beefy impact gun on hand for their removal, and don’t make the mistake of unbolting one side completely before tackling the other, especially if the K-member is unsupported.  10 As the saying goes: "many...  10 As the saying goes: "many hands make for light work," especially when it comes to lowering the factory K-member/control arm assembly. Actually, it’s not as heavy as you might think, but the new one is much, much lighter.  11 Here’s how the students...  11 Here’s how the students dropped the old K-member—complete with steering box, lower control arms, lower ball joint assemblies, and the Demon’s aftermarket adjustable strut bars. The only things to be reused are the ball joint assemblies, and even these will be modified for use on the CAP suspension parts.  12 When installing a coil...  12 When installing a coil over front end, and eliminating the torsion bars, a support must be made for the coilover to mount to. Don't mount the coil over directly to the existing shock tower, as this area is not designed to support the weight of the car, and it will eventually fail. Here you can see the brackets and tubular structural support that are now welded in place to take the spring loads of the coil over shocks. These were engineered in-house by instructor, Bob Williams, at Jefferson High School’s fabrication shop, and were used to create jigs so CAP Auto Products can now sell duplicates to A-Body owners wishing to go the coilover route. Those retaining their torsion bars can ignore this altogether and simply get on with the job of bolting up the new K-member.  13a Before bolting up the...  13a Before bolting up the new K-member, a steering-adapter u-joint is connected to the factory steering shaft...  13b ...Before you can install...  13b ...Before you can install the u-joint, you must first remove the cross pin that goes through it.  14 On goes CAP’s tubular...  14 On goes CAP’s tubular K-member assembly, complete with steering rack and lower control arms (those big bolts get torqued to 220 lb-ft) Note that customer getting rack-equipped K-members will also get modified OEM spindles pre-attached. In this regard, you have the option of sending your factory spindles to CAP for a core exchange, or purchasing new ones from them. If you’re not purchasing a rack-equipped k-member, your OE spindles will not need modified. Once the new K is in, and the engine mounts re-secured, any external engine support can be removed.  15 This spindle mod that...  15 This spindle mod that CAP performs involves welding on this new steering link that we are so stylishly pointing out (remember that opting for the rack-and-pinion setup changes the car from a rear-steer design to front-steer.) This means the steering linkage connections are moved from the rear of the spindle stem (see image 5) to the front of the spindle (see image 6).  16 For the same reason, the...  16 For the same reason, the old (rear-facing) steering link can be sawn off the lower ball joint assemblies (about where our trusty trigger finger is pointing on this display suspension.) Again, this is of course only if switching to rack-and-pinion.  17 Here, the guys have secured...  17 Here, the guys have secured the tie-rod end and upper ball joint to the new spindle, and are in the process of bolting the lower ball joint assembly to the spindle.  18 With the rotor and caliper...  18 With the rotor and caliper back in place, bolting the coilover to the lower control arm and the welded-in top bracket is among the final steps. Clearly, the threaded body of the coilover assembly allows for simple ride height adjustment.  19 Speaking of adjustment,...  19 Speaking of adjustment, there’s plenty (both horizontal and vertical) built into CAP’s tie-rod end hardware to facilitate a proper bump-steer elimination setup, regardless of ride height. For you A-Body guys in the audience, this is about the correct vertical setup for “normal” ride height.  20 Those of you familiar...  20 Those of you familiar with the normally cramped quarters on the steering side of the A-Body’s engine bay will recognize how much real estate CAP’s rack-and-pinion-equipped K-member opens ups. You can aslo see the finalized steering shaft with the two u-joints. That and the roughly 105-pound weight savings should be sufficient incentive to look into CAP Auto Products’ offerings. mm
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