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2001 to 2010 Chevy Silverado and GMC Sierra 2500HD Coilover Conversion: Part 1

BDS’s GM 2500/3500HD Lift Install: Part 1 of 2

May 22, 2019

What once was old is now becoming cool again. Music from the 1980s, clothes from the 1990s, and trucks from the early 2000s. Well, at least that's how it's going in our world. New trucks are expensive, and if you want to modify them at all, the price tag shoots up to levels that our minds have trouble comprehending. That's why, when we decided we wanted to build an HD diesel pickup, we opted to go a route that's becoming more and more popular: We bought old.

Our tireless Internet searching brought us to a 2002 Chevrolet Silverado 2500HD. The truck was equipped with an LB7 Duramax engine (though most of it was in the bed), and it had a perfectly straight crew cab body along with a rust-free frame. We were able to snag this specimen for just $3,800, quickly loading it on our trailer and hitting the road before the seller knew what he had done. Once back at our lab we slowly rebuilt the drivetrain, turning the box of parts into a 650hp fire-breathing monster.

Photo 2/26   |   Our canvas wasn't completely blank to start, as our Silverado came to us with 33-inch tires and a torsion key leveling kit. Even still, the truck was in desperate need of an attitude adjustment and the still-factory suspension was quite the back-killer.

With the truck driving again, it was time to turn our attention to the suspension, and the good folks at BDS Suspension had exactly what we were looking for. With the ultimate goal of stuffing 37-inch tires on the truck with as little lift as possible, we opted for BDS's newest offering, a 4.5-inch coilover conversion. You read that right, we were set to ditch the rough-riding torsion bar springs that GM has been using for decades for the plusher comfort of race-proven Fox 2.5-inch coilover shocks.

Since we'd built nearly every other part of the truck thus far, we decided now was not the time to call in a shop. With that in mind, we tirelessly pored over the installation instructions and laid out a plan to install the kit by ourselves, in our driveway, with no professional supervision. Right off the bat it's worth mentioning that while this lift kit can be installed in DIY fashion, to do so you'll need a good set of tools, knowledge of how automotive suspension systems work, and a decent amount of fabrication experience. You'll also need special tools for working on the Chevy HD, such as a quality torsion bar unloading tool, 35mm hub socket, and more.

Photo 3/26   |   We decided early on that we were going to tackle this project in true do-it-yourself fashion. Starting with the front first we jacked the truck up in our driveway, took the front wheels off, and supported it with jackstands.

BDS claims the install time for this kit is between 8 to 10 hours. We call shenanigans on that. Spoiler alert, we spent (one person, working on the ground) approximately 60 hours from start to finish. To be fair, we also stripped and coated the framerails along with all parts that were reused, replaced all of the steering system, and also installed BDS's new Recoil traction bars. Even still, we're betting it's closer to a two-day job for an experienced shop.

Come along as we take a look at just some of the work that went into getting our Silverado ready for the lift and the first half of the installation.

Photo 4/26   |   After more than 200,000 miles the front suspension on our Silverado had seen better days. An engine oil leak left the driver side coated in thick grime, while the passenger side was dry as a bone. Thankfully, a lifetime in the desert Southwest meant we were starting with a rust-free platform.
Photo 5/26   |   Front suspension
Photo 6/26   |   It may seem obvious but before the new suspension can be installed the old needs to be removed. The only parts we planned to reuse were the lower controls arm and brakes. While not necessary, now is a good time to upgrade the steering as well as replace wear items such as the lower ball joint, unit bearings, and axle halfshafts.
Photo 7/26   |   While there are a lot of bolt-on lift kits that can be installed with no fabrication needed, this is not one of those kits. The factory bump and droop stop mount will need to be removed from the frame to make room for the coilover shock.
Photo 8/26   |   BDS cautions that the frames of GM trucks have a coating applied that is flammable. Because of this, it's recommended to not use a torch or other cutting implement that could cause the coating to ignite. That said, the easiest way to remove the mount is with a plasma cutter. We pulled out our trusty Miller Spectrum 375 X-treme and carefully made our cuts. We also kept a fire extinguisher close at hand, just in case.
Photo 9/26   |   After cutting the bracket off the frame, we took an angle grinder with a sanding disk and smoothed out the frame. The instructions give a detailed overview of exactly where to cut and should be followed carefully.
Photo 10/26   |   The fabrication fun doesn't end with the frame brackets. After removing the front differential, the rear crossmember, which connects the rear lower control arm pockets, needs to be trimmed. BDS provides a plate that needs to be welded in place once the crossmember is cut.
Photo 11/26   |   Before welding the filler plate in place, we stripped the control arm pocket of the frame undercoating and cleaned everything thoroughly. Our Millermatic 211MIG welder made short work of burning in the plate.
Photo 12/26   |   With the cutting and welding complete, we stripped the framerails of their remaining dirt, grime, and undercoating. We then used Steel-It polyurethane aerosol spray paint to freshen everything up prior to beginning the installation of fresh BDS parts.
Photo 13/26   |   Steel-It polyurethane aerosol spray paint result
Photo 14/26   |   One of the core components of the lift kit is the bracket that bolts to the frame and facilitates installation of the Fox coilover shocks. This bracket attaches to the factory shock mount along with four -inch bolts on the face.
Photo 15/26   |   BDS recommends marking the location of the four holes and then drilling them with a 9/16-inch bit. You'll want to use a strong drill and copious cutting fluid to lubricate the bit as the frame can be tough to punch through.
Photo 16/26   |   To get the nuts onto the bolts inside the frame BDS has offered this ingenious solution. By welding short pieces of metal onto the nuts we were able to fish them into the framerail through the control arm pockets.
Photo 17/26   |   BDSs GM 2500 3500HD Lift Install Part 1 016
Photo 18/26   |   The -inch bolts are torqued to 65 ft-lb and, in theory, the metal tabs will hold the nut firm while tightening. Of the eight bolts, we only had one tab break off before reaching the full torque spec. And while the nuts are deformed-thread locknuts, we also applied bountiful thread-locking compound for good measure.
Photo 19/26   |   In addition to the four frame bolts, there's a stud at the top of the bracket that goes through the factory shock mount and gets torqued to 95 ft-lb. This stud also secures the shock reservoir mount.
Photo 20/26   |   Most of the height increase is achieved by use of lower crossmembers and a larger knuckle. The front BDS crossmember goes in first and gets secured with the factory lower control arm bolts. By using a floor jack to aid in lifting the crossmember, we were able easily align the bolt holes.
Photo 21/26   |   To accommodate the lift the differential gets lowered as well. The factory upper mount on the differential is cut off and replaced by a bolt-on BDS part. Then a drop bracket is affixed to the passenger-side mounting point. This bracket both lowers the axle and corrects the pinion angle.
Photo 22/26   |   Using a floor jack and the help of a strong friend, the front differential can be raised back into place. The new upper mount secures to the front crossmember while the factory lower mount will eventually bolt to the new rear crossmember. All bolts are left loose at this point and will be tightened when everything is in place.
Photo 23/26   |   Moving attention to the factory lower control arms, BDS supplies a bracket that accommodates the lower mounting point of the new Fox coilovers. Before installing the bracket, a large aluminum spacer needs to be slid into the factory torsion bar pocket.
Photo 24/26   |   Some control arms will require light grinding of the flashing line on the lower control arm to get the new bracket to sit flush. We needed a little light sanding on one of the two arms. Aftermarket replacement lower control arms won't work at all, BDS claims. The lower coilover mounts bolt to the arms with the factory lower shock mount bolts and the provided -inch bolt through the aluminum spacer.
Photo 25/26   |   While we had the suspension apart, we took the opportunity to freshen up the sway bar as well. We hit up RockAuto.com and ordered a pair of new ACDelco bushings to replace the worn factory units. The bushing straps come off with four bolts and changing the bushings takes no time at all.
Photo 26/26   |   After installing the new lower coilover brackets and new Moog ball joints from RockAuto.com we were able to hang the lower control arms in the new BDS crossmembers. At this point, we were about halfway done with the installation process.
Sources:

BDS Suspension

www.bds-suspension.com

Miller Welders

www.millerwelds.com

RockAuto.com

www.rockauto.com

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