Quick answer: A universal swivel seat base is a component for a custom conversion, not a vehicle-specific bolt-on kit. Every installation needs a lower mounting platform and an upper seat connection. Compare the approximately 43mm single base and 100mm slider assembly only after checking the complete mounting height, rotation clearance and installation requirements with your fabricator.
Want the front seat to face the living area when you stop for a break? The swivel mechanism is only one part of that conversion. A comfortable result also depends on the seat’s final height, the space it needs to turn and a properly designed connection to the vehicle.
Is a universal swivel seat base right for your conversion?
The EVparts4x4 360° seat swivel base is a steel, handle-release mechanism for custom projects. It can be considered for different vehicle types, including cars, SUVs and campervans, but each seat-and-vehicle combination needs its own mounting assessment.
“Universal” does not mean the original seat holes will line up, the existing pedestal can be reused unchanged or the conversion will be approved for road use. Establish these three points before choosing a base:
- Mounting design: who will make the lower platform and the upper seat adapter, and how will they connect?
- Space and seating position: is there enough headroom, legroom and clearance through the intended rotation?
- Use and assessment: will the modified seat be occupied during travel, and what evidence will the assessor require?
Brief the workshop before buying the mechanism
Provide the seat model, vehicle details and photographs of the seat underside, floor or pedestal, belt attachment and under-seat wiring. A fabricator needs this information alongside dimensions; a make/model selection alone is not a mounting design.
43mm single base or 100mm slider assembly?
The two options solve different packaging needs. The single base is the lower-profile component; the slider version adds integrated fore-aft adjustment. Neither includes the custom parts that connect it to your seat and vehicle.
Swipe sideways to compare all columns on a small screen.
| Check | Single Swivel Base | Swivel Base with Slider Tracks |
|---|---|---|
| Approximate component height | 43mm | 100mm, including the slider assembly |
| Integrated fore-aft tracks | Not included | Included |
| Worth considering when | The mounting plan needs a lower-profile swivel without integrated tracks | The plan needs fore-aft movement and has room for the taller assembly |
| Custom mounting parts | Required | Required |
The listed component-height difference is 57mm. That is not automatically the difference in final seat height: the two installation plans may use different platforms, adapters or retained rails.
The listing describes four 90° locking positions for the slider option. Confirm the supplied unit’s locking arrangement and the required driving position; parking detents are not approval to travel in every orientation.
Plan the lower platform and upper seat adapter
Every vehicle requires custom mounting connections. The lower frame provides the support, height and attachment suited to the vehicle; the upper connection matches the seat underside. Both form part of the complete seat-mounting design.
Below the swivel
A fabricated platform or frame connects to the assessed floor structure, pedestal or suitable rails. Its height and fixing positions must suit the vehicle, not just provide a flat surface for the turntable.
Above the swivel
An adapter plate or bracket arrangement connects the selected base to the seat. The mounting pattern, seat underside and operating clearances determine its shape and fixing positions.
The supplier identifies steel plate or angle steel as possible fabrication materials. Have the qualified installer specify the material dimensions, reinforcement, hole positions and joining method. Welding is an option only after assessing the structure, materials and mechanism.
Swipe sideways to read the full table on a small screen.
| Part | Included or arranged separately? |
|---|---|
| Selected swivel mechanism | One unit included; slider tracks are included with the slider option only |
| Vehicle seat | Not included |
| Lower mounting platform or frame | Custom part, not included |
| Upper seat adapter plates or brackets | Custom parts, not included |
| Installation fasteners | Not included; specified for the mounting design |
| Fabrication, fitting and assessment | Arrange separately |
Measure the final seat height and rotation clearance
Do not treat 43mm or 100mm as the amount your seat will rise. Ask the fabricator to compare the complete old and new mounting stacks using the same floor reference and the same seat.
Plan the complete mounting stack
Estimated height change = added mounting height − removed mounting height.
Add the new platform, swivel, upper adapter and any new rails. Count integrated slider tracks once. Subtract the height of parts removed; unchanged retained parts cancel out and are excluded from both sides.
- Seat and base interfaces: seat-hole spacing, underside shape, both swivel mounting faces and the required fixing access.
- Occupied seating position: head-to-roof space, legroom, pedal reach where relevant, sightline and access to controls.
- Rotation envelope: console, doors, handbrake, furniture and the rear of the seat through the intended movement.
- Slider movement: clearance over the full planned travel, including release-handle access.
- Floor structure: proposed attachment areas and anything underneath, including wiring, pipes and other vehicle components.
- Restraints and cables: seatbelt attachment, buckle, pretensioner and airbag wiring; no pinching, snagging or stretching through movement.
Request a dimensioned drawing and operating details for the selected base before the workshop finalises the adapters. Do not copy hole spacing or slider travel from another swivel that looks similar.
Agree the installation and approval route
Use a qualified fabricator or installer experienced with vehicle seating. Agree the mounting design and required assessment before fabrication, especially if the seat carries a belt anchorage or contains restraint-system components.
- Assess the existing seat and vehicle. Record the mountings, restraints, wiring and intended travelling position.
- Confirm the component and evidence. Match the chosen variant, dimensions and locking details to the proposed installation and assessor’s requirements.
- Design both mounting connections. Specify the lower frame, upper adapter, reinforcement and fixing or joining methods for this vehicle.
- Trial-fit the complete stack. Check occupied height, rotation, slider travel, handle access and cable clearance before completing the work.
- Complete the specified installation. Use the designed fasteners and procedures; obtain the installation-specific torque values rather than guessing.
- Inspect, assess and hand over. Check mounting security, locking and affected restraint systems, complete the required assessment and retain the fitting records.
Australian road vehicles
Confirm the applicable seating and anchorage requirements with your local registration authority or approved signatory before work starts. For example, the NSW modified-vehicle guidance explains certification for significant modifications. Other Australian jurisdictions have their own approval arrangements.
New Zealand road vehicles
The LVVTA seat-swivel guidance identifies aftermarket swivelling front-seat bases as requiring LVV certification and supporting testing documentation. Discuss the exact base, seat and mounting design with an LVV Certifier before ordering for road use.
Rotate only when parked. Before moving, return and positively lock the seat in its assessed driving position. A working swivel or locking detent does not establish that every direction is an approved travelling position.
If the seat has integrated belt loads, airbags, pretensioners or sensors, have those systems assessed as part of the conversion. Do not bypass restraint equipment to make the seat turn.
Compare the complete conversion cost
The base price is only one line of the job. Obtain a workshop quote that includes the lower platform, upper adapters, installation fasteners, fabrication, fitting and any required inspection or certification.
Allow for additional work if the plan affects a handbrake, pedestal, restraint wiring or existing seat rails. The finished height and approval route can matter more than the price difference between the two mechanisms.
Check the selected variant’s current price and currency on the product page, then review the shipping policy and returns policy. Do not treat a catalogue installation-time estimate as the time needed for a complete custom conversion.
Ready to discuss a base option?
- The workshop has a route for both mounting connections.
- The complete seat height and movement envelope have been checked.
- The selected unit’s dimensions, locking details and required evidence are available.
- The applicable assessment and full conversion cost are understood.
View the swivel base configurations
For component questions, send your measurements and photographs to EVparts4x4. For other adaptable components, browse the Universal Fit collection; each part still needs its own installation assessment.
Frequently Asked Questions
Is this a direct-fit swivel seat kit for my car, SUV or campervan?
No. Universal means a component for custom adaptation. Every vehicle needs a suitable lower platform and upper seat connection. The vehicle name or VIN alone does not establish that the seat, mounts, clearances and approval requirements are suitable.
Which version should I choose: the 43mm base or the 100mm slider?
The single base has an approximately 43mm listed component height and no integrated slider tracks. The slider assembly is approximately 100mm and includes fore-aft tracks. Choose after your fabricator has planned the complete mounting stack, required adjustment and clearances.
Will the swivel raise my seat by exactly 43mm or 100mm?
No. Those figures describe the listed component heights. The platform, upper adapter, retained or added rails, and any original mounting parts removed determine the change in seat height. Compare the complete new and old mounting stacks using the same reference points.
What is included with each option?
The Single Swivel Base includes one swivel mechanism without integrated slider tracks. The slider option includes one swivel base with its slider-track assembly. A seat, vehicle-specific platform, upper adapter plates or brackets, and installation fasteners are not included.
Do I need a custom platform underneath the base?
Yes. The lower mounting frame or platform must suit the vehicle floor, pedestal or suitable rails and provide the required support, fixing points and height. Its design and connection to the vehicle must be specified for the individual installation.
How does the top of the swivel connect to my seat?
An upper adapter plate or bracket arrangement must match the seat underside and mounting dimensions. For bolted connections, the hole positions and fasteners are specified as part of the complete mounting design; a matching-looking plate is not enough.
Can steel plate or angle steel be used, and can I weld the base?
The supplier identifies steel plate or angle steel as possible fabrication materials. A qualified installer must decide the dimensions, reinforcement and joining method. Welding is only an option after that assessment; it is not permission to weld to any seat frame or floor.
Will the seat rotate through a full 360 degrees once fitted?
The base is designed as a 360-degree mechanism, but the installed seat can be restricted by the console, door, handbrake, furniture or wiring. Check the complete rotation envelope and handle access before fabrication. Slider travel also needs clear space.
What if my seat has an airbag, belt buckle or seatbelt anchorage attached?
Have the restraint-system layout assessed before work begins. The design must address any seat-mounted belt loads, pretensioners, sensors and wiring affected by movement. Do not bypass restraint equipment to obtain clearance or make the seat rotate.
Does universal fitment mean the finished installation is road approved?
No. Check the approval route and required evidence before purchasing for a road vehicle. Australian requirements depend on the relevant jurisdiction; LVVTA specifically identifies aftermarket swivelling front-seat bases in New Zealand as requiring LVV certification.
Can I rotate or use the seat sideways while driving?
Rotate this product only when parked. Before moving, return and positively lock the seat in the assessed driving position. Mechanical parking detents do not make every facing direction an approved travelling position.
Is there a published load rating or a fixed installation time?
The public specification does not give a tested load rating for this component. Obtain the evidence required for your design before ordering. Measurement, fabrication, restraint-system work and inspection also make the total installation time specific to the project.
