Chassis Modifications Brisbane – Certified & Customised Vehicle Engineering
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Looking for trusted chassis modifications in Brisbane or across South East Queensland? At Stewart & Sons Engineering, we specialise in ADR-compliant and VASS-approved chassis modifications, engineered for performance, safety, and certification across a wide range of vehicles.
Whether you need to extend your chassis, upgrade suspension systems, or carry out axle conversions, our team brings over 75 years of fabrication and vehicle engineering experience to every job. From commercial fleet trucks to one-off custom vehicles, we deliver reliable, roadworthy results—backed by full compliance with Queensland Department of Transport requirements.
We proudly issue VASS modification plates and handle all legal documentation, so you can stay focused on the road ahead.
Why Choose Us for Your Chassis Modifications?
✔ Registered and certified engineering shop
✔ Over 7 decades of experience in truck and ute modifications
✔ VASS plate issued for road compliance
✔ Local expertise for Brisbane and Queensland conditions
✔ Custom fabrication in-house for superior turnaround times
Brisbane Chassis Extensions – Engineered to Last
A chassis extension may be required if you’re upgrading to a longer tray, converting a vehicle’s purpose, or shifting your axle placement for better weight distribution.
At Stewart & Sons Engineering, we perform precise chassis extensions on a variety of commercial and fleet vehicles. Each job is custom engineered using high-quality steel, ensuring structural integrity, longevity, and compliance with Queensland regulations.
Our wheelbase modifications include:
- Chassis lengthening
- Wheelbase extension or reduction
- Tray repositioning for custom builds
- Reinforced crossmember fabrication
- Lazy axle installations
Truck Chassis Modifications Queensland
Truck configurations often need to be adjusted for legal payload limits, performance improvements, or specific commercial applications. We provide tailored truck chassis modifications throughout Brisbane and regional QLD.
Our Services Include:
- Trailing and leading third axle conversions
- Spring and air suspension upgrades
- Lazy axle supply and installation
- Heavy-duty welding and fabrication
- Crossmember and brace reinforcement
- Suspension kits for load management
- Custom truck body mounting brackets
Whether you’re converting for freight, farming, or trade use, we’ll optimise your truck’s chassis to suit local road conditions and load requirements.
All modifications are performed in accordance with the Queensland Transport & Main Roads modification standards and certified with a VASS modification plate.
Fully Compliant with Queensland Transport Standards
We understand the legal requirements for roadworthy modifications in QLD. As part of our service, we’ll:
- Engineer your chassis modifications to spec
- Issue a VASS (Vehicle Assessment Signatory Scheme) modification plate
- Supply all documentation for your vehicle registration
- Advise on load ratings and suspension impacts
We work closely with transport operators, farmers, government bodies, and trade vehicle owners to ensure all modifications are fully compliant and documented correctly.
Get a Free Quote on Chassis Mods in Brisbane
Ready to modify your vehicle’s chassis for performance, safety, or new commercial uses?
📞 Call Stewart & Sons Engineering on (07) 4151 3977
📩 Or contact us online for a tailored quote
We serve clients throughout Brisbane, Logan, Ipswich, the Sunshine Coast, and beyond. Our Bundaberg-based workshop delivers chassis upgrades that hold strong—on-road and off.
Frequently Asked Questions
We work on utes, trucks, trailers, and specialty vehicles used in agriculture, trades, transport, and logistics.
Timeframes depend on the complexity, but standard extensions typically take 1–2 weeks. We’ll confirm timelines during your consultation.
Absolutely. We offer full third axle conversions and install both spring and air suspension kits to meet load requirements.
While our workshop is located in Bundaberg, we regularly complete jobs for Brisbane-based clients and can coordinate vehicle transport if needed.