Commercial Trailer Repair & BIT Inspection FAQs

Yes. TruMac utilizes heavy-duty cribbing and 20-ton hydraulic jacks to lift fully loaded trailers (up to 80,000 lbs) on-site. We remove the damaged leg or sheared cross-shaft and install new Jost or Holland landing gear right in your yard. This saves you the cost of a heavy-haul tow and cross-docking fees.

Learn more about our mobile landing gear repair services →

See Rancho Cordova landing gear project →

Yes. We provide dedicated mobile service to the entire Rancho Cordova logistics corridor, including White Rock Road, Sunrise Blvd, and the Mather Airport Industrial Park. Our service trucks are stocked for emergency repairs at distribution centers and fleet yards throughout the 95670 and 95742 zip codes.

We serve major distribution hubs and logistics facilities in Rancho Cordova, Sacramento, Stockton, Modesto, Tracy, Fairfield, and throughout Northern California. Call or text (916) 320-2425 for same-day service.

View all mobile repair services →

The 60/40 rule states that 60% of the cargo weight should be loaded in the front half of the trailer (closest to the hitch/kingpin) and 40% in the back. This prevents dangerous trailer sway (fishtailing) and ensures proper tongue weight distribution for safe towing.

Why it matters: Improper weight distribution is a leading cause of trailer accidents, jackknifing, and loss of control. Overloading the rear causes the trailer to whip side-to-side, especially at highway speeds or during emergency braking.

Proper weight distribution also reduces stress on landing gear and suspension components, extending their service life and preventing costly breakdowns.

Learn about kingpin and coupling system maintenance →

The Basic Inspection of Terminals (BIT) is a California-mandated safety inspection required every 90 days for commercial vehicles with a GVWR of 10,001+ lbs. It covers critical safety components like brakes, lights, tires, and coupling devices. TruMac performs these inspections on-site to keep your fleet compliant with CHP regulations.

What's Inspected:

• Brake systems (air brakes, stroke adjustment, chamber condition)
• Lighting and electrical systems
• Tires and wheels (tread depth, damage, proper inflation)
• Coupling devices (fifth wheel, kingpin, glad hands)
• Suspension components
• Frame and body integrity

Schedule your 90-day BIT inspection today →

See West Sacramento brake repair project →

Technically, yes, if you are qualified. However, California law requires that the inspector understands the vehicle's systems and inspection criteria. Most fleets outsource this to TruMac to ensure unbiased reporting, liability protection, and professional documentation for CHP audits.

Why fleet managers choose professional BIT inspections:

• Third-party validation protects against liability claims
• Certified documentation stands up in CHP roadside inspections
• Professional mechanics catch issues before they become violations
• Saves time—your drivers stay on the road

Learn about fleet yard service programs →

Common signs include excessive heat coming from the wheel hub after driving, a grinding or growling noise, grease leaking onto the tire or rim, and noticeable wheel wobble. If you see smoke or smell burning rubber, pull over immediately—bearing failure can lead to wheel detachment.

What causes bearing failure:

• Lack of lubrication or contaminated grease
• Improper bearing adjustment (too tight or too loose)
• Water intrusion through damaged seals
• Overloading the trailer beyond capacity
• Normal wear after high mileage (100,000+ miles)

Emergency bearing service available 24/7. Call (916) 320-2425 if you suspect bearing failure.

A worn kingpin will show "slop" or movement when coupled, often felt as a clunk when starting or stopping. We measure the kingpin's diameter with a micrometer against the SAE standard (2.00" - 0.125"). If it is worn beyond tolerance or mushroomed, it must be replaced or resurfaced to prevent uncoupling accidents.

Kingpin Inspection Procedure:

• Measure kingpin diameter at multiple points using precision calipers
• Check for mushrooming (expanded top surface from repeated coupling)
• Inspect for vertical movement or excessive play in the fifth wheel
• Test coupling/uncoupling action for smoothness

A worn kingpin is a CSA violation and can result in an out-of-service order during CHP roadside inspections.

Learn about mobile kingpin replacement service →

It depends on the trailer's frame condition. For commercial dry vans, replacing worn leaf springs, torque arms, or air bags is significantly cheaper than buying a new trailer. However, if the sub-frame or hanger brackets are rusted through, the structural integrity may be compromised. We provide an on-site assessment to determine the ROI of repair vs. replacement.

Repair Cost Comparison:

• New Trailer: $35,000 - $50,000+
• Complete Suspension Overhaul: $3,000 - $8,000
• Air Bag Replacement (per axle): $400 - $800
• Leaf Spring Replacement: $600 - $1,200

If your trailer has less than 200,000 miles and the frame is solid, suspension repair is almost always worth it.

Air bag suspension troubleshooting guide →

The most common causes are dry-rotted air bags, leaking height control valves, or chafed air lines rubbing against the frame. In winter, moisture freezing in the lines can also cause valve failure. We use ultrasonic leak detectors to pinpoint issues quickly.

Leak Diagnosis & Repair Process:

• Soap solution test on all air bag seams and valve connections
• Ultrasonic leak detection for hard-to-find pinhole leaks
• Inspection of air line routing to prevent future chafing
• Height control valve calibration after component replacement

Most air suspension leaks can be repaired on-site within 1-2 hours. We carry OEM air bags for Hendrickson, Neway, and Reyco suspension systems.

Complete air bag troubleshooting guide →

No. TruMac is a dedicated commercial fleet service. We specialize in heavy-duty dry vans, reefers, flatbeds, and chassis used in logistics. We do not service recreational vehicles, horse trailers, or passenger cars.

What we DO service:

• 53' Dry Van Trailers (Wabash, Great Dane, Utility)
• Refrigerated Trailers (Thermo King, Carrier units)
• Flatbed & Step Deck Trailers
• Container Chassis (20', 40', 45')
• Dump Trailers & End Dumps

Our focus on commercial equipment means we have the specialized tools, parts inventory, and expertise your fleet needs.

Learn about our fleet yard service programs →

A "mobile mechanic" typically handles roadside emergencies for any vehicle. TruMac Fleet Maintenance partners with logistics yards to provide scheduled preventative care, BIT inspections, and yard-based repairs. We focus on fleet uptime and compliance, not just fixing breakdowns.

Fleet Maintenance vs. Mobile Mechanic:

• Fleet Maintenance: Scheduled service contracts, preventative maintenance programs, compliance tracking
• Mobile Mechanic: One-time emergency repairs, no ongoing relationship

TruMac offers:

• 90-day BIT inspection programs with digital record-keeping
• Preventative maintenance schedules (PMI) customized to your fleet
• Priority emergency response for contract customers
• Fleet analytics and failure trend reporting

View fleet maintenance programs →

Yes. TruMac is one of the few mobile services in Northern California that performs kingpin replacement at your yard. This rare specialty service eliminates expensive towing costs and keeps your trailers in service. We bring all necessary equipment including welding and pressing tools.

Why Kingpin Replacement is Rare:

• Requires specialized pressing equipment (20+ ton hydraulic press)
• Demands precise welding for structural integrity
• Must meet SAE J133 specifications
• Most shops require trailers to be towed in

We perform kingpin replacement on-site at fleet yards in Sacramento, Stockton, Modesto, Tracy, Fairfield, and throughout Northern California. Contact us for photos of recent kingpin projects.

Learn more about kingpin replacement service →

We specialize in fleet yards operating 100+ commercial trailers. Our contract programs are designed for logistics operations in Sacramento, Stockton, Modesto, Tracy, Fairfield, and surrounding Northern California distribution hubs. We provide parts and maintenance programs tailored to your fleet size and utilization patterns.

Fleet Services Include:

• Scheduled preventative maintenance programs
• 90-day BIT inspection contracts
• Parts inventory management
• Priority emergency response
• Fleet analytics and maintenance tracking

Request a fleet service proposal →

No. TruMac focuses exclusively on scheduled yard-based maintenance and fleet yard emergency service. We do not provide freeway or roadside breakdown service. This specialization allows us to deliver faster response times and better quality work in controlled fleet environments.

Why Yard-Based Service is Better:

• Safer working conditions for technicians
• Access to full tooling and equipment
• Higher quality repairs without time pressure
• Better diagnostic capabilities
• Lower costs compared to roadside emergency rates

View our service area coverage →