Symptoms
Steering that wanders or clunks, the box moving on the rail, or cracks around the box bolts. It's most likely on lifted trucks with big tires.
The fix, step by step
- Clean the driver's-side frame rail and inspect it closely.
- If it's cracked, stop-drill the crack and weld in a repair plate first.
- Offroad Design sells a weld-on frame repair kit for 1973–91 GM trucks.
- Then fit a bolt-in steering-box frame brace, which ties the box mount across to stiffen the rail.
- Re-torque the box and brace bolts after the first few hundred miles.
Tools & part numbers
- Wire wheel
- drill
- socket set
- torque wrench
- MIG welder for crack repair
Where to buy the parts
Bolt-in steering box frame brace, 1973–1991 4WD GMC/Chevy full-sizeOffroad Design ↗Amazon ↗
Weld-on frame repair kit, '73–91 GM trucksOffroad Design ↗Amazon ↗
Hunting a used or discontinued part? Search eBay Motors for Chevrolet/GMC Suburban (1973–1991 square body) parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.