Frequently Asked Questions About Kenworth W990 Drum Brake Parts

Will these drum brake parts fit my specific year model W990?

Most drum brake components for the Kenworth W990 are compatible across model years 2018-2024, as the brake system design has remained consistent. However, always verify the part number matches your VIN specifications. Key measurements to confirm include drum diameter (typically 16.5" x 7" for front and 16.5" x 8.625" for rear), brake shoe width, and S-cam spline count. If you're unsure, contact us with your VIN and we'll help identify the exact parts you need.

What's the difference between OEM and aftermarket brake shoes, and which should I choose?

OEM brake shoes typically use premium friction material rated for 23,000 lbs per axle and come with exact factory specifications. Aftermarket options from brands like Meritor and Gunite often provide comparable performance at 20-30% less cost. The main differences are friction material composition and expected lifespan - OEM shoes generally last 150,000-200,000 miles under normal conditions, while quality aftermarket options achieve 120,000-180,000 miles. For severe-duty applications or maximum uptime, we recommend OEM. For standard highway use, certified aftermarket parts offer excellent value.

Can I replace just the brake shoes, or do I need to replace drums and hardware too?

You can replace brake shoes independently if your drums measure within spec (no more than 0.120" over original diameter) and show no heat cracks, scoring deeper than 0.035", or out-of-round conditions exceeding 0.015". However, we strongly recommend replacing hardware kits (springs, pins, and bushings) with every brake shoe replacement - these $30-50 kits prevent uneven wear and premature failure. If drums are near maximum diameter or show any damage, replace them simultaneously to avoid comeback issues and ensure proper brake balance.

What tools and expertise do I need to install these drum brake parts myself?

Drum brake replacement requires specific tools including a brake spring tool, drum puller, brake adjustment gauge, and proper jack stands rated for commercial vehicles. The job typically takes 2-3 hours per axle for experienced technicians. Critical steps include proper shoe-to-drum clearance adjustment (0.020-0.030"), correct S-cam timing, and proper slack adjuster setup. While mechanically inclined owners can perform this work, improper installation can cause brake imbalance, premature wear, or failure. We recommend professional installation unless you have commercial vehicle brake experience and proper tools.

How do I know when it's time to replace my W990's drum brake components?

Replace brake shoes when lining thickness reaches 1/4" (6.35mm) at the thinnest point or if you notice increased stopping distances, brake fade, or uneven wear patterns. Drums need replacement when they exceed maximum diameter stamped on the drum (typically 0.120" over original) or show heat checking, deep scoring, or bell-mouthing. Other warning signs include slack adjusters requiring frequent adjustment, visible oil contamination, or any DOT out-of-service conditions. Regular 90-day inspections help catch issues early and prevent roadside failures.