Hummer H3 Mod: Improving Flex

Jun. 06, 2007 By Manny MacMillan
As many are discovering around the country, the Hummer H3 is a decently capable 4x4 right off the showroom floor.  Most off-road enthusiasts are quick to look for ways to improve their rigs’ off-road abilities.  As a driver gets more comfortable with the truck and learns how to push the limits with a truck, the ways to expand those limits become more and more apparent.

Rob Sutter has already fitted his 2007 Hummer H3 with 35’s and he has been wheeling his H3 regularly.  As he took on progressively more challenging trails, he began to notice something that many owners of “near-stock” vehicles encounter – limited flex. Obviously the independent front suspension has some more complex obstacles to overcome when it comes to improving the suspension articulation, but the rear is an old school straight axle configuration, and as such the H3 is a prime candidate for some classic modifications to improve flex in the rear.  Specifically, longer shackles to hang the rear springs, longer shocks to prevent the shock from being a limiting factor, and a set of quick disconnects for the rear sway bar.


There aren’t a lot of options out there for functional bolt-on H3 parts yet, but there are some parts out there that will work.  Rob made some calls and talked with some folks at a few different suppliers before settling on a handful of new parts that were designed primarily for use with Jeeps, and we went to work to make them fit. 


One advantage of working with an H3 is that none of them are very old.  With less than 30,000 miles on the ticker, the bolts on this truck all came off with relative ease.  Rob was able to swap out the four shocks and the shackles for the leaf springs in short order.  The whole job could be done with simple hand tools by even the most basic shade-tree mechanic.  An impact wrench and air ratchet will make the job go much faster, and your knuckles will thank you if you have some long extensions to work with as well. 


The quick disconnects presented a couple of challenges.  Getting the old OEM links off required vice grip pliers to keep the ball joint from spinning endlessly as the nuts were removed, but all in all getting them off was not a problem.  It was apparent that the new parts were designed for a different application, however.  The shaft of the parts was too long, and the offset from one head to the other was not perfectly lined up.  The ball joint at each end of the OEM sway bar links on a Hummer H3 allow for a diagonal position through much of the range of motion during regular operation.  The replacement parts had no such joint, using a straight pass-through bolt on each end, and lacking the flexibility to operate along the same diagonal lines.  Fortunately, we were able to scrounge up a few extra washers from around the shop to correct the spacing and make the parts work. 


Ultimately, the shafts on the disconnects will need to be shortened a few inches (nothing that a bandsaw and a drill press can’t fix in a couple of minutes), and the best way to tie the detached sway bar up and out of the way will probably need to be determined through some trial and error, but overall the results were excellent.  The on-road manners of the truck are excellent with the sway bar links attached, and as you might expect the improvement in flex on the rear of the truck is immediately noticeable when the links are disconnected.


Rob field tested the modifications the next day at an off-road trail event, and it performed very well – a significant improvement over stock that was apparent to driver and onlookers alike.  In Rob’s own words, “Crazy mad flex! …the best $300 mod any H3 driver could ever make.” Newsletter
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