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Three Things We Did To Improve Our 1995 Chevy Suburban’s IFS After A Torsion Bar Lift

Our goal was to better our Suburban’s ride quality, suspension travel, and CV shaft angles.

Our ’95 Suburban was a bargain several years back thanks to a blown transmission. Since taking ownership, we’ve rebuilt the 4L60E with just about everything you can throw at it, swapped in a rear semi-float 14-bolt, installed 4.56 gears with a Eaton Detroit Truetrac in the rear, dropped in a mildly-built 350-c.i. V-8 that was collecting dust on the stand, installed performance front brakes, and now finally upgraded the front suspension.

One of the most inexpensive and quickest ways to lift torsion bar-style IFS is by increasing the preload on the torsion bars, commonly referred to as "cranking the torsion bars." There can be downfalls to this method. Harsh ride quality, limited suspension travel, and increased CV shaft angles can be some or all of the primary results. It is possible however to avoid these things following a torsion bar lift. How is this accomplished? Well, there are complete kits available from aftermarket suspension companies that address these issues. However, we set out to address these issues by using the a la carte method for our 1995 Chevy Suburban that came to us with a torsion bar lift completed by a previous owner.

Our Suburban Had Bad Ride Quality Among Other Things
When we purchased this 1995 Chevy Suburban, plans of a solid axle swap were right at the top of the list but quickly dropped off as other aspects of the vehicle were modified or repaired, and other project vehicles entered the picture. Plus, this vehicle serves as a road trip machine that's used to traverse mild, scenic trail systems, and it's not a dedicated trail rig. This being said, the previous owner cranking the torsion bars created a domino effect, and among other things, the ride quality both on and off road was less than desirable, to say the least. It was time to remedy that.

Our ’95 Suburban was a bargain several years back thanks to a blown transmission. Since taking ownership, we’ve rebuilt the 4L60E with just about everything you can throw at it, swapped in a rear semi-float 14-bolt, installed 4.56 gears with a Eaton Detroit Truetrac in the rear, dropped in a mildly-built 350-c.i. V-8 that was collecting dust on the stand, installed performance front brakes, and now finally upgraded the front suspension.

Problem Solving
We set out to improve three major functions of the IFS on this Suburban: 1) Increase the suspension travel through installation of aftermarket upper control arms 2) improve shock damping by installing quality monotube shocks and 3) correct the CV shaft angle by lowering the differential through installation of a differential drop kit. While the truck will always have a stiffer ride due to preload on the torsion bars, addressing these three areas will dramatically increase ride quality and suspension performance while still utilizing the existing aftermarket torsion bar keys and factory torsion bars. With the exception of having to fabricate a couple of differential drop brackets (more on that in a minute), installation of the components was fairly straightforward. We're pleased to report that after the mods, the Suburban suspension handles much better and the overall ride quality has been dramatically improved. Here are the highlights of what we did:

It's good practice to take measurements whenever you're conducting modifications or repairing on the front suspension to record a baseline for setting up new parts in the suspension. This will help take some of the guesswork out of getting the alignment close to spec. Using our caster camber gauge, we took measurements before starting in order to get our baseline data.
We took a measurement at full droop for before and after comparison.
Looking closely at the upper control arm resting on the bumpstop, you might think this picture was taken at full droop. It is full droop; however, it's also how close the upper control arm was at normal ride height. Downtravel was virtually nonexistent. The metal on metal contact greatly contributed to the very harsh ride we'd been experiencing.
Tip: When removing the front differential on '88-'06 GM IFS, disconnect the draglink, and turn the steering wheel full lock. This will move the pitman arm out of the way of the differential and make for a much easier time removing the differential.
We opted to try this low-buck 2-inch differential drop kit found on eBay to correct the CV shaft angles. We thought about fabricating our own drop kit but opted for this kit instead. The parts seemed to be of good quality and looked identical to some other aftermarket drop kits. Turns out, a couple of the brackets would not work with our Suburban, and we ended up having to fabricate new ones.
Our Suburban has spent a majority of its time at Marine Corps bases in warm climates, which resulted in a clean, rust-free vehicle. Now that we've relocated to northern Indiana, rust prevention is a continuous task. So with the brakes off and shocks out, we took the opportunity to apply a coat of rust prevention paint. Tip: Marking your eccentric bolts will give a good starting point with getting the caster and camber in spec after install.
We had to cut off the rearmost mounting flange in order to install the differential drop bracket. We ground down overlapping metal to a flush surface.
The fitment of the upper differential drop brackets just didn't work. A recess in the supplied brackets designed to accommodate the lip that protrudes from the bottom of the truck's mounting point didn't line up. This resulted in the brackets dropping down at an angle out of line with the differential mounting point. Due in part to a tight schedule, we opted to fab some simple drop brackets. The plasma cutter made quick work of the 1/4-inch flat bar steel we used to make the brackets.
Seen here installed, the passenger-side diff drop bracket is very straightforward. We just unbolted the factory mounting bracket and bolted in the new drop bracket. Instructions for the rear differential drop bracket called for drilling through the back side of the control arm mount and running bolts through the original mounting location and also through the drilled back side of the control arm mount.
A transmission jack or adapter plate for a floor jack made removal, installation, and jockeying the differential around the shop a breeze. The cooling fins on the driver side of the differential, close to the rear mount, needed to be ground down due to interference with the drop bracket.
We chose Rough Country upper control arms and Rancho RS7000 MT monotube shocks to address our downtravel issue and lack of proper damping. The Rough Country upper control arms, which fit models with 2-3 inches of suspension lift, are designed to allow for full downtravel and increased clearance to the upper strut mounts. The arms feature pressed-in ball joints and Clevite brand OEM-style rubber bushings. To address damping issues, we installed a pair of Rancho RS7000 MT shocks that are 2 inches longer than stock. Features include application-specific deflective disc valving, a 1.97-inch-diameter body, a high-pressure nitrogen gas charge, free-floating dividing piston, and double welded loops. These things help create a shock that is ideal for extreme off-road use and larger wheel and tire packages.
We used a floor jack to raise each steering knuckle, which helped with installation of the upper control arms. Leverage is your friend when wrestling with quality monotube shocks, and a medium size breaker bar was our tool of choice for assisting with shock installation.
Following installation of the new components a measurement at full droop with the truck still on jackstands revealed an almost 2-inch gain in downtravel, which is significant. The final step was to have the Suburban's frontend aligned. The end result of the modifications was vastly improved ride and handling and corrected CV shaft angles.

Sources

Rancho
800/325-8886
gorancho.com

Rough Country
800/222-7023
roughcountry.com