Brake systems
Brakes diagnosed fast. Fixed right the first time.
Slack adjusters, air lines, chambers, drums, shoes, and full brake system rebuilds for box vans and trailers. Parts in stock. Techs who know the work.
Brake problems on a trailer don't get better on their own. A slow leak becomes a fast leak. A worn shoe becomes a damaged drum. A sticky slack adjuster becomes a DOT out-of-service violation. Knox Trailers diagnoses brake issues the day you bring the trailer in, fixes them right, and gets you back on the road without the second trip.
Brake work we run every day
Slack adjuster service
Manual and automatic slack adjusters inspected, adjusted, or replaced. Stroke measurement, ratchet function, clevis pins, and S-cam alignment all checked.
Air system repair
Air line leaks traced and fixed. Glad hands, gladhand seals, air valves, relay valves, and air dryers replaced or rebuilt as needed.
Brake chamber replacement
Service brake chambers and spring brake chambers diagnosed and replaced. Type 20, 24, 30 brake chambers in stock for common applications.
Drum and shoe replacement
Drums turned or replaced based on wear measurement. Shoes replaced with quality friction material. Hardware kits standard with every shoe replacement.
Hub and bearing service
Wheel bearings inspected, repacked, or replaced. Seal replacement standard with hub work. Oil bath hubs serviced for trailers equipped.
ABS diagnosis and repair
ABS warning light diagnosis. Wheel speed sensor replacement, ECU testing, modulator valve service. ABS ring inspection during regular brake work.
Schedule the work or get a quote.
Mon–Fri 7am–6pm. Same-day appointments most weeks.
What good looks like
When you bring a trailer to Knox Trailers, here's what you should expect.
- Diagnosis within 30 minutes of dropping the trailer off
- Quote with photos and explanation before any work starts
- Most common brake repairs completed same-day with parts in stock
- DOT-compliant work documented for your records
- Brake stroke measurements and air leak-down test results provided
- Follow-up call within 30 days to verify no issues
Why fleet managers send brake work to us
Brake work is what separates real shops from places that just turn drums. We measure stroke, find air leaks with proper soap testing, check the suspension components that affect brake performance, and document our work. When you get your trailer back, the brakes work the way they're supposed to — and you have paperwork showing what we did.
We also stock the parts. Type 20 and Type 24 brake chambers, slack adjusters from the brands you trust (Haldex, Bendix, Meritor), brake shoes with hardware kits, ABS components. Most brake repairs don't require an overnight wait for parts.
Common questions
Can you do brake work on a tight schedule?
Most brake repairs are completed same-day or next-day. If the trailer is already at the shop, we can usually have it back to you within 24 hours. Emergency brake work for our regular fleet customers gets priority routing.
Do you use OEM parts or aftermarket?
Both, depending on your preference and the application. We default to OEM-quality friction and air system components from Haldex, Bendix, Meritor, and similar. We'll quote alternatives if cost is a factor.
What about reefer trailer brakes?
Reefer trailer brakes use the same air system as dry vans. The reefer unit doesn't affect brake work. We handle brake jobs on dry vans, reefers, flatbeds, and box vans equally.
Related services
DOT Inspections
Annual inspections, follow-up corrections, fleet PM programs. We get your trailers compliant and back on the road without the runaround.
Learn more →Mobile Service
Mobile service trucks dispatched same-day for trailer repair at your yard, the highway, or wherever you broke down. We carry common parts. We bill less than your downtime costs.
Learn more →Structural Repair
Frame straightening, floor replacement, wall and door repair, rear-frame rebuilds. Welding, alignment, and refurbishment done in-house by techs who know structural work.
Learn more →Ready to get it fixed?
Same-day appointments most weeks for fleet customers. Call or request a quote and we'll get you scheduled.