Installing a MaxTrac Suspension Lowering Kit on a 2014 GMC Sierra

When it comes to trucks, position is everything and that says a lot about what a vehicle stands for. If the truck is lifted, it’s off-road time, in most cases. If the truck is still at ride height, it’s probably heading to Home Depot to haul lumber. We wanted the position of our supercharged 2014 GMC Sierra Project Truck to tell people that this pickup was built to haul butts. We wanted to lower the ride height to accomplish this task, which sent us to MaxTrac so that the parts do the job properly.

Powder coated leaf spring shackles and new shorter shocks for the rear and some cast iron drop pins for the front were just the parts we needed from MaxTrac to lower our GMC Sierra in the wrong herbs.

Most trucks come from the factory with a standard rake in the ride height, which means the rear is higher than the front. This is done so when a heavy load is placed in the bed of the truck, the rear springs compress, and then as the loaded vehicle rolls down the street, the headlights don’t shoot at the stars.

Because our truck will be spending its days racing down the drag strip instead of racing to the job site, we wanted to remove the factory rake when we lowered it. To get the right ride height, we wanted to lower the rear 4 inches of the truck while lowering the front 2 inches to give us a flatter stance. The MaxTrac lowering kit for a 2014-2018 GMC Sierra/Chevrolet Silverado drops the front 2 inches using new pins and lowers the rear between 4 and 5 inches depending on the holes used on the rear shackles, which was perfect for our application.

The MaxTrac Lowering Kit reuses the stock rear leaf springs (reversed and placed in the new MaxTrac mounting clevises) and depending on which hole you screw the leaf springs into, you can lower the rear ride height by 4 or 5 inches.

When choosing a lowering kit (and there are plenty to choose from), one specific feature that sold us on the MaxTrac system was the design and engineering that went into the replacement front pins. Rick Freeman, MaxTrac’s Technical Specialist, detailed the benefits of his product.

“Our 2014-18 GMC/Chevy spindle design is the best and strongest casting on the market. The MaxTrac spindle uses all three bolts to hold the factory hub, where other major competitors only use two of the factory bolts and one set screw that tends to shear. Rick also explained that the drop pin design was set up so that it lowers the truck, it doesn’t give you a bump in alignment.

A factory GMC/Chevy hub uses three bolts to hold it in a spindle and the MaxTrac lowering spindle has three holes to accommodate those three bolts. Other manufacturers that build lowering skewers only use two of the three bolts to fit in a stock hub with a set screw that tends to shear.

With our parts lined up and the Sierra on the lift, it was time to stop talking about lowering that truck and getting our hands dirty. We started from the front because reading the MaxTrac installation instructions—yes, we read the instructions before doing a project—it seemed like replacing the front pins would be pretty straightforward.

We unbolted the ball joint, link, hub and ABS sensor from the stock pin, then inserted the new lowering pin. Everything bolted easily to the new lowering pins. The only thing we changed was the ABS sensor bracket, which needs to be cut to fit the spindle with enough slack in the ABS thread. This was done quickly with a grinder. After this slight modification, everything worked fine.

Replacing the stock front pins with the MaxTrac lowering pins was as easy as unbolting the stock pin and replacing the new pin. No exits.

With the front of the truck lowered, without drama, it was time to turn our attention to the rear of the Sierra. The rear was more involved because we had to remove the fuel tank. This is where some planning ahead helps. Truck fuel tanks are large, and fuel tanks filled with lots of gasoline are cumbersome to manage. Luckily, we brought the Sierra to the shop with low fuel, so dropping the tank wasn’t a complete headache. However, the tank had to be removed to gain access to the inner leaf spring bolts and the driver’s side clevises.

The big tank is out! Pro Tip: Do not attempt to pull out a full tank of fuel (too heavy). Start with something empty and light. We had to pull the tank out to access the rear leaf spring bolts.

Once we removed the outer cover and removed the fuel tank, we unhooked all the connections to the tank, including the EVAP tank, which likes to leak fuel all over you. We then used a transmission jack to lower the tank out of the way. Next, for easier access to the leaf springs, we removed the trailer hitch and rear exhaust outlets. Finally, we had seamless access to the rear suspension we wanted to modify. Because we were going to be removing the rear leaf springs and shock absorbers, which hold the axle in place, it’s essential to use a bolt-on mount to hold the axle securely, because no one needs just one truck axle falls on its head.

With the truck on the lift and the rear shocks and leaf springs sticking out, something was needed to hold the rear axle in place or gravity was going to take over. We put a screw holder under the pumpkin to hold it in place.

With everything out of the way and easy access to the leaf springs and their mounting points, it was time to get serious. The MaxTrac kit replaces the original leaf spring shackles. However, these stock shackles are bolted, riveted and welded to the frame. It means it was time to sparkle. First, we had to cut/grind/chisel the factory shackles from the frame to make room for the powder-coated versions of MaxTrac. Then it was time to grind and do our best to protect our fingers from the spinning grindstone.

It’s time to spark some sparks while grinding the factory spring shackles.

The good news was that even though we had to cut and grind the stock shackles, the MaxTrac powder coated shackles bolted directly into place using the stock bolt holes in the frame, which meant no drilling in the frame was necessary. But before bolting them on, we hit the bare areas of the frame with spray paint to make sure we wouldn’t have rusting issues in the future. Also, some of the bolts used to hold the spring shackles in place are also rear bumper mounts, so we didn’t drop the rear bumper for installation. However, this part of the job requires some help from friends, aligning the right bumper as you tighten all the bolts.

With the stock shackle ground down and fresh paint on the frame, we began installing our new powder coated shackles from MaxTrac.

The rear lowering suspension kit is a rocker design that moves the stock leaf spring from the top of the axle down. The bolt in the center of the leaf spring must be reversed or turned over to accomplish this process. Next, a leaf spring locator is attached to the bottom of the axle. This requires cutting the brake line bracket (simpler grinding job). Next, U-bolts and plates are installed to sandwich the leaf springs and secure them to the bottom of the rear axle. It is important to torque the U-bolts to specification at this point to properly preload the springs. Next, we installed the shorter MaxTrac shocks, which bolted on right away.

Seth Ward takes care of installing the inverted leaf springs under the rear axle (which were originally located above the axle) by tightening the U-bolts.

When we bolted the leaf spring to the new MaxTrac shackle, we chose the lowest bolt hole on the shackle, giving us the drop of 4 inches instead of 5 inches. The last thing to do was to remove the stock bumper, both metal and rubber, from the frame, which required more grinding. Max Trac provides a shorter urethane stopper to replace the stock part.

We had to quickly modify our recently installed JBA exhaust system to accommodate the new rear spring shackles. The good news is that there are enough adjustments in the JBA system to realign things and get us back on the road.

Our previous project on the Sierra was installing JBA headers and cat-back exhaust for more power. But like any hot rod project where multiple parts are applied to a vehicle, adjustments must be made. For example, MaxTrac’s rear spring shackle was found to be a little lower than the OEM part, conflicting with our aftermarket JBA exhaust pipe. This was quickly remedied by adjusting the twist of the slip-fit ​​pipes and using a new exhaust hanger.

With the drop in ride height, we realized we had to change the aspect ratio of our tires and go for a tire with a shorter sidewall. It was also a great opportunity to select a tire with more grip to handle the power coming from our supercharged LS engine. After some research and after reviewing the tires, we settled on the Yokohama PARADA Spec-X Street/Sport Truck all-season 285/45/22 inch tires. As soon as we mounted/balanced them and on the Sierra, we immediately knew this was the perfect tire for the position we were hoping to achieve.

A set of Yokohama PARADA Spec-X Street/Sport Truck All-Seasons tires were used to get the position right.

The Yokohama PARADA Spec-X Street/Sport Truck All-Season tires were noticeably more grippy in the dry, and they also handled much better in the rain than the Goodyears, which were previously on the truck. Also, there was no noticeable increase in tire noise from the Yokohamas, which was great so we could enjoy the sound of the JBA exhaust as we propelled the supercharged Sierra down the highway. The next stage of this project will be the drag strip as we will see what all of our new modifications do on the track compared to our stock times. So stay tuned…

With our MaxTrac lowering kit installed, our JBA exhaust tuned and a new set of Yokohama donuts on the rims, the stance on the Sierra was right on and the truck was ready for a proper test drive.

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