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Jimenez Bros. Customs’ Universal Two-Link - Back DropFrom the July, 2011 issue of Rod & Custom By Rob Fortier
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As we’ve all seen in print and even online, lowering the front of early Chevy passenger cars (’37-54) can be as easy as unbolting the old and bolting in the new. And with the aid of additional modern technology, the frontal ride height can be drastically reduced. However, to do so on the opposite end with an equal drop takes a little more effort than simply busting out your basic hand tools; bolt-on leaf kits are limited to the space between the bottom of the top-hat framerail and the rearend axle tube. Having already been equipped... Having already been equipped with a Heidts frontend (currently outfitted with coilovers, which will soon make way for ShockWaves), the rear suspension on my Fleetline needed to be addressed in a major way. I won’t have a custom with its nose lower to the ground than its rear, period. But even with a decent C-notch, leaf-spring-based rear suspensions have their pre-determined limits, thus adding a similar type of adjustable component as the frontend (i.e. airbags) ultimately defeats the inherent function of the leaf to begin with. For many, including myself once or twice in the past, the solution was to remove individual leaves from the spring pack. With a dual-convoluted air spring, which acts as a coil, it’s not so badbut when using a sleeve-type ’bag, that’s where the mechanical issues can arise. Leaf springs were not designed to act as adjustable locators for your car’s rearend. There are options, but unfortunately, they’re not as inexpensive as the aforementioned bolt-on kits, nor are they as straightforward installation wise. If your goal is to go as low (or lower) than your frontend, you’ll want to consider going with either a parallel or triangulated four-link or a truck armstyle two-link. Four-links are almost as popular as Mustang IIs these days, and because of that, there’s a good variety to choose from. (If this is the direction you decide to go, definitely go the triangulated route.) However, the two-links are gaining more and more popularity as of late, and you’re about to see why. The solution—Jimenez Bros.... The solution—Jimenez Bros. Customs’ (JBC) new adjustable two-link kit, complete with RideTech airbags, on a Moser Engineering Muscle Pak 12-bolt rearend with two-piece driveshaft from Inland Empire Driveline. Form (lowness) and function all in one. With a properly designed two-link (or trailing arm) setup, you have a rear suspension with no compromised componentseverything works in unison, giving you ample adjustability and potential for great ride quality. You also end up with a more user-friendly geometry of parts that offer both better ease of installation as well as room to route your forthcoming exhaust once all’s said and done. And it was partly owing to this that inspired Jimenez Bros. Customs (JBC) to come up with its own two-link kit. The setup JBC offers has plenty of flexibility fitment wise, so its application goes well beyond the ’37-54 Chevy you’re about to see it installed on (at the time this was done, they were also fitting one to a ’50 Mercwhich didn’t need the step notch due to its high arcing rear ’rails). JBC’s two-link consists of square-tube trailing arms with bolt-on/adjustable rearend mount, adjustable forward-link mount crossmember, four-piece step notch kit, tubular upper shock mount, shocks, Panhard bar, and airbags (which we sourced from RideTech along with a two-way RidePro setup). JBC’s two-link comes compete... JBC’s two-link comes compete with square-tube trailing arms with a bolt-on/adjustable rearend mount, adjustable forward-link mount crossmember, four-piece stepnotch kit, tubular upper shock mount, shocks, Panhard bar, and airbags (from RideTech along with a two-way RidePro setup). Before we could incorporate everything, we needed to do something about the rearend. This is also something many of you will be faced with, especially those of you still running the stock closed driveline. Because we wanted to go the Chevy route rather than the usual Ford 9-inch, we went to Moser Engineering and asked them what they recommended. As it turned out, they suggested a little of both12-bolt housing with 9-inch-style flanges and 30-spline axleswith one of their Muscle Pak complete rearend kits. And by kit, they mean drum-to-drum, chrome differential cover to pinion yoke, and even e-brake cables and hardware. Once the new rearend arrived from Indiana, JBC had their first prototype two-link ready to installthat is, once the ’47 Fleetline body had been removed from the chassis and all the factory obtrusions rid of.  JBC’s two-link comes compete...  JBC’s two-link comes compete with square-tube trailing arms with a bolt-on/adjustable rearend mount, adjustable forward-link mount crossmember, four-piece stepnotch kit, tubular upper shock mount, shocks, Panhard bar, and airbags (from RideTech along with a two-way RidePro setup).  If at all possible, removal...  If at all possible, removal of the body allows for substantially less “overhead” work and gives you a much better vantage point for plotting out and installing components. But, the kit does not require it for installation purposes. Once we pretty much got everything stripped from the trans crossmember back, the frame was leveled on jackstands.  Starting with the stepnotch...  Starting with the stepnotch portion, using the stock wheelbase gave us a starting point. Because the rear wheels on the ’42-48 Chevy two-door Aerosedans (Fleetline) aren’t exactly centered, we made the necessary adjustments to ensure they would be, especially at ride height. You don’t want to rely on fender skirts to conceal an error that can easily be avoided now.  Once the side plates are squared...  Once the side plates are squared up and where they’re supposed to be (in relation to the wheelbase), they’re welded to the frame. The metal thickness on the main portion of these frames is rather thin and fragile, so short weld sections were made to prevent any damage from excess heat.  Next, the flat plate top sections...  Next, the flat plate top sections are welded in place. Starting from top center (with the plates themselves centered), they’re tacked in sections and then bent accordingly as you work your way down to the framerail.  Now, with the sides and tops...  Now, with the sides and tops welded up—and the frame supported from BOTH sides of the notch—the portion of framerail can be removed from the notch section using either a plasma cutter or a Sawzall.  The final component of the...  The final component of the notch, the inner hoop, will tie everything together and re-establish the integrity of the framerail.  The inner plates are supplied...  The inner plates are supplied slightly longer than may be necessary—just trim off the excess as needed.  The three holes on each side...  The three holes on each side of the boxing plates are not only used for welding purposes, but also to indicate front (two holes) and rear (one holes) positioning.  Now we could turn our focus...  Now we could turn our focus toward the actual suspension, starting with the Moser Muscle Pak rearend. Since this is a 12-bolt, having had its ring-and-pinion already set up by Moser, it remained in place, but the axles/brakes would not. Fortunately, the external-flanged axle housing made it much easier to do so, rather than having to remove any C-clips from the differential.  Basically, we’ll bolt all...  Basically, we’ll bolt all the components together, from the forward-mount crossmember to the two-link U-bolt mounts on the rearend, before welding anything in place.  The blocks that mate the trailing...  The blocks that mate the trailing arms to the rearend’s axle tubes actually bolt to the arms, making it much easier to assemble everything with just two hands, as shown.  The blocks that mate the trailing...  The blocks that mate the trailing arms to the rearend’s axle tubes actually bolt to the arms, making it much easier to assemble everything with just two hands, as shown.  The front crossmember for...  The front crossmember for the trailing arms has sliding frame mounts, allowing for any adjustment if needed. Ultimately, the ends will get welded to the crossmember as well as the framerail.  The front crossmember for...  The front crossmember for the trailing arms has sliding frame mounts, allowing for any adjustment if needed. Ultimately, the ends will get welded to the crossmember as well as the framerail.  With the links installed onto...  With the links installed onto the rearend first, they’re simply lifted up and installed on the crossmember. Having the rearend perched on a floorjack will help in positioning everything when determining and setting the desired wheelbase.  The pinion angle can be set...  The pinion angle can be set simply by loosening the U-bolts to allow the rearend to rotate. When all’s said and done, we’ll most likely weld the blocks to the axle tubes, but considering the amount of horsepower/torque the car “won’t” have, that may not be totally necessary.  Now for the upper airbag mounts....  Now for the upper airbag mounts. These will be supplied as shown on the right—pre-drilled but flat with slots for bending the side gussets (as illustrated on the left in the vise).  At this point, both the ’bag...  At this point, both the ’bag mount and the upper shock mount have been tacked in place simply by installing the ’bag/shock on the lower mounts and cycling the rearend through its range of estimated travel. No real science there, but still plenty of room for error.  Only after we were 99.9 percent...  Only after we were 99.9 percent sure the mounts were in the proper locations, at the proper angle, did we proceed with final welding.  The last item to be welded...  The last item to be welded onto the frame was the Panhard bar mount, which uses a flat plate base welded to the frame that the tabs are attached to, making for a stronger piece with less stress on the thin ’rail.  With everything fully welded...  With everything fully welded up, including the opposing Panhard bar bracket, we were finally able to run the suspension through its full range of travel, and in doing so, not only determined that all components were functioning properly, but that we had over 7 inches of suspension travel.  Thanks to Inland Empire Driveline,...  Thanks to Inland Empire Driveline, we can utilize much of that travel without having to compromise severe driveshaft angles with their two-piece slip-joint-style ’shaft. Featuring a compact, billet-housed carrier bushing and smaller diameter driveshaft tube, the two-piece setup will keep us from having to do major tunnel work to the car’s floor as a one-piece would.  And there you have it, an...  And there you have it, an adjustable and sensible rear suspension setup that will ultimately go a long way toward the Fleetline’s overall driveability once she’s on the road. But before that can happen, we’ll have to swap out the front coilovers and install a four-way air management system. More to come …
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