How to Rebuild the Front Suspension on your 1997-1999 OBS 4X4: Step by Step

[1998Suburban]

After 18 years and 177K miles the front suspension on my '98 K1500 Suburban was starting to hurt. She wandered on the interstate and I found myself aiming in a general direction as opposed to actually steering her. I looked for a good rebuild thread but couldn't find an all-in-one that specifically covered control arm bushing and ball joint replacement. I figured I'd write one based on my rebuild experience.

As my truck was blessed by living in MA, ME, CT, and NY during her early years I had some pretty crusty looking suspension parts:



I now live in area that doesn't use much road salt and has 2 u pull it's within a reasonable driving distance. I decide to keep an eye out for a good donor so I could start with rust-free components. This beauty showed up and was exactly what I needed. This '99 even had the HD torsion bars:

After a long day with hand tools I had everything I needed. Rust free Upper control arms, lower control arms, torsion bars, keys, adjuster, and a pile of bolts and associated fasteners. I'll get into the specifics of stripping the front end a bit later on as I didn't take many pictures here. You can see it was a muddy mess that day.

Anyway after a trip to the car wash I cleaned up my new control arms:



I was pleased with them. Little to no rust and they cleaned up well. Next stop was Rock Auto to order Moog parts for the rebuild. FYI the '97-'99 uses a stamped lower control arm with a high press force design ball joint. GM sweetened the pot by using green Loctite on the lower ball joints so they are tight.

I picked up the ball joint service loaner kit from Advance Auto as it had 4x the adapters than Auto Zone's kit. The OE ball joints take up the entire shoulder of the LCA flange. In order to press these ball joints out I used the sleeve that has a "V" notch in it on the receiver end. This allowed the outer edge of the ball joint to move freely.


These ball joints are a TIGHT press fit! I ended up putting the control arms in my 20 ton press and I saw the press frame deflect as it loaded up.

I ended up making 4 tools for this project: I ground down an old CV axle nut so it fit inside the LCA bushing, fabricated 2 sleeves from an old ball joint service kit to support the LCA while removing and installing the bushing, and used a piece of conduit (silver) from Lowe's to service the UCA bushings:



Using the ground down nut and longer sleeve I removed the large LCA bushing. The sleeve with the "V" referenced earlier is visible in the tool tray


The shorter LCA bushing is crimped and these crimps must be ground off prior to removing the bushings. The photo of the crimped bushing is from the crusty LCA I removed:


Here's what the bushing looks like after the crimps have been ground off and the bushing has been removed.



At this point the LCA is stripped and the new bushings and ball joint are ready to be installed. To install the bushings I used a BFH (big $$$$$$$ hammer), the supports fabricated earlier, and the appropriate socket to drive them home. When installing the larger bushing the cutout should be installed near the torsion bar hex. The slot is visible on the old bushing:


Next are the UCA bushings and ball joints. The upper control arm is a wire form design. I started off by grinding the heads off the rivets holding the upper ball joint in place. Then i was able to separate the ball joint from the control arm:


At this point I ground, hammered, beat, and otherwise cajoled the rivets out of the upper control arms. Ultimately I ended up using a handful of grade 8 bolts and the press to press each one out. They were VERY stubborn:


The upper control arm bushings were fairly straightforward to remove using the sleeves in the loaner tool kit. At this point the control arm is stripped and ready for new components:


Using the piece of conduit from Lowe's the upper control arm bushings can be installed with the C clamp in the ball joint service kit. As mentioned the lower bushings were installed with the sledge:


Once the bushings have been installed the control arms are ready for new ball joints:


The upper ball joints are bolted in using the supplied bolts, while the lowers are pressed in. As mentioned the lower ball joints are a high press force design. I was unable to fully install them with the C clamp in the service kit and had to go back to the 20 ton press. When installing be sure to align the Zerk fitting with the depression in the end of the control arm.

The rebuilt control arms are now ready to go on:


In addition to having rust-free components to put on the truck pulling/rebuilding the control arms beforehand limited my truck's down time. I did add a coat of POR-15 for both longevity and aesthetics:

 

[1998Suburban]

Now it's time to tear into my front suspension. A cursory look at the front suspension shows why I wanted to get rust-free control arms. The uppers don't look good:



And the lowers are just as bad:


If you aren't using air tools I'd break the 36MM CV axle nuts loose prior to lifting the truck off the ground. If you can shimmy under the truck it's also a good time remove the lower nut from the sway bar end link. The LCA needs to be level in order to access the nut. When I removed the original end links I cut them as they were rusted solid. The replacements used a 9/16" nut.

Now it's time to get the truck up in the air. Once she's securely off the wheels you can break the 6 15MM CV joint to stub axle bolts loose. This is best done prior to pulling the brakes as you can stick a screwdriver in the cooling vanes of the brake rotor (new rotor shown). The screwdriver will strike the caliper and keep the brakes/CV joint from rotating:



Next remove the brake caliper, rotor and shock. You'll need an 18MM socket and combination wrench for the shocks. The larger bolt is on top and the nuts are on the passenger compartment side of the truck. At this point the front end looks as follows:



If you're planning to change the hub and bearing assembly now's the time to break the 3 15MM hub nuts loose. They can be quite stubborn. Here's what one of mine looked like after losing the fight with a bolt extractor:



If your hub and bearing assembly has never been out you'll need a slide hammer (27033) and suitable adapter to pull the hub from the knuckle. I'd already replaced mine and I reassembled with a liberal coat of anti-seize so they came right out.

To break the ball joints free from the steering knuckle you'll need a pickle fork type ball joint separator (27020) and a pickle fork type tie rod end separator (27025). Remove the 18MM nut from the tie rod end and separate it using the separator and a sledge hammer. If replacing the innner/outer tie rod end assembly separate the inner tie rod end using a pitman arm separator (27022). You may need to kiss the inside of the puller with a Dremel or die grinder so it can fit on the relay rod.

Remove the upper and lower cotter pins and loosen but DO NOT REMOVE the 27MM lower bolt and upper bolt. Clearance is tight between the upper ball joint bolt and CV joint so I used an adjustable wrench. I used the tension from the torsion bar to help break the ball joints free of the steering knuckle. This is why I loosened but didn't remove the nuts.

 

[1998Suburban]

Using the pickle forks and sledge hammer pop the ball joints loose. Before removing the nuts you need to relieve the tension on the torsion bars. The GM torsion bar tension adjusting tool (27278) fits in a dimple on the cross member and sits in the inner dimple of the torsion bar key. Tighten the tool until there's no pressure on the 18MM bolt that rests in the outer dimple. Remove the 18MM bolt and key, then relieve tension on the torsion bar tool.

Now remove the upper and lower ball joint nuts completely and remove the steering knuckle.


Remove the CV axle:


Now loosen the 24MM nuts/bolts on the lower control arm. One of my bolts rotted to the inner sleeve of the bushing and was a bear to break free. I used the impact wrench on one end and a sledge on the other to get it moving. If you're lucky the control arm isn't rusted to the torsion bar. One of mine came free and the other was rusted solid.

If your torsion bar is rusted to the control arm remove the torsion bar cross member (2 18MM nuts/bolts and 1 15MM nut/bolt on a Suburban, Tahoe/Yukon is a bit different). The torsion bar separates from the key and the key can be removed. Below are the torsion bar, key, 18MM adjuster bolt, and retainer:


As the lower control arm and torsion bar were fused together I had to remove them as a unit:


This torsion bar isn't budging:



Fortunately I didn't have to mess with this as I had the HD torsion bars from the donor '99:

 

[1998Suburban]

Remove the 21MM nuts/bolts and remove the upper control arm. Remove the lower jounce bumper if you're replacing it. At this point the front suspension has been completely stripped and you're down to the bare frame:


After some additional cleanup and a coat of POR-15:


If the frame knock outs for your upper control arms haven't been removed now is the time to push them out. Mine had already been done and one was off center. It was ugly but I didn't see a good way to clean it up:


Time for assembly!

First install the lower control arm. The bolts are fairly loose at this point (10-15 ft-lb). In order to easily install the torsion bars and sway bar end links the control arm should be level. I used a 2"x4" and a bottle jack to level the control arm. It's holding the arm in position but is not supporting any weight. After the lower control arm, jounce bumper, torsion bar, and end links are in place install the upper control arm. These bolts and adjuster cams are installed loosely as well

Wrap a towel, rag, etc. around the outer boot on the CV axle and install. The 15MM bolts are only finger tight at this point. Now install the steering knuckle and make the upper and lower ball joints snug. Install the shock and torque upper and lower bolts to 66 ft-lbs:

Next install the torsion bar key and use the tensioning tool to load the torsion bar. Install the bolt and keeper. Initial setting for a 4WD 1/2 ton truck is 34MM as measured from the bolt head to the keeper. Remove the tension tool.

Torque the upper and lower ball joint nuts. Uppers are 75ft-lb, lowers are 95 ft-lb. Install the supplied cotter pins.

Install the tie rod end and torque to 46 ft-lbs. Torque the hub and bearing assembly nuts to 133 ft-lbs. Install the brake rotor and caliper:


Use the screwdriver in the brake rotor to keep the CV axle from rotating and tighten the 15MM cv axle to stub shaft bolts. Put the wheel back on and lower the truck (assuming both sides are done), then torque the 36MM CV axle nut to 165 ft-lbs.

Check ride height and ensure the truck is level. The final setting on my torsion bar adjusting nuts was 25MM vs the 34MM starting point.

With the vehicle's weight on the wheels torque the Upper control arm bolts to 140 ft-lbs. Next torque the lower control arms to 121 ft-lbs. I put her up on ramps to access the lowers. Tighten the sway bar end links.

Your alignment will be awful until you make it to the alignment rack but you're ready for a test drive!

Here's the front end supporting the truck:


Take a test drive and treat yourself to a donut or frosty beverage! That was a lot of work!!

 

[TheAutumnWind]

This is a fantastic post, but I am not seeing any of the images!

 

[1998Suburban]

Hmm.. I'm not sure why you can't see the pics. I put them in Photobucket and the album is public. I can still see them after I log out. Maybe site admin can take a look and figure out what's going on?

 

[SunlitComet]

This is a fantastic post, but I am not seeing any of the images!

you're not special.

 

[TheAutumnWind]

you're not special.

Respectfully, my wife tells me that you are wrong sir.

Well... special-ed anyways.

 

[SunlitComet]

 

[Donnie Yukonie]

Great Post , Good Job with the pictures and torque specs! Ill sticky this