ENDRUST® UB302B — Heavy-Duty Bituminous Underbody Coating

Professional Underbody Rustproofing for Long-Term Corrosion Protection

ENDRUST® UB302B is a professional-grade, high-build bituminous rustproofing coating designed to protect vehicle underbodies, chassis and running gear against corrosion and demanding operating conditions.

Based on polymerised bitumen and formulated with rust converters and corrosion inhibitors, UB302B forms a tough, flexible and adhesive protective barrier against moisture, salt, mud, gravel and road debris.

Its thixotropic formulation provides excellent seam penetration while minimising sagging and runs during application. The cured coating also helps reduce road and tyre noise through its sound-deadening properties.

UB302B is the primary coating used in Endrust’s heavy-duty bituminous underbody rustproofing systems.

Features & Benefits

• Heavy-duty corrosion protection: Forms a durable barrier against moisture and environmental contaminants.
• Rust converters and inhibitors: Suitable for direct application over properly prepared light surface rust.
• Flexible protective coating: Helps withstand vibration, road impact and normal vehicle movement.
• High-build formulation: Provides substantial protective film thickness.
• Excellent seam penetration: Reaches joints, seams and irregular underbody surfaces.
• Sound deadening: Helps reduce road and tyre noise.
• Versatile application: Suitable for vehicles, machinery, trailers and industrial equipment.

Recommended Applications

UB302B is suitable for:

• Passenger vehicles, 4WDs, utes and commercial fleets.
• Chassis rails and cross-members, including accessible internal chassis surfaces.
• Wheel arches, floor pans and underbody structures.
• Axle and differential housings, gearbox and transfer case housings.
• Trucks, trailers, caravans and recreational vehicles.
• Mining, agricultural and industrial machinery.
• Underbody repairs and maintenance.

UB302B is also used inside chassis rails in Endrust Premium Epoxy specifications, where ENDRUST® UB702 protects the external chassis and underbody surfaces.

Technical Information

Surface Preparation & Application

Surface preparation depends on the condition of the vehicle or equipment.

New vehicles and light surface rust: Clean and dry the surfaces, removing loose dirt, grease and contamination. UB302B contains rust-converting and corrosion-inhibiting components and can be applied directly over suitable light surface rust.

Moderate to heavy rust: Remove loose and flaking rust by mechanical preparation, then treat with ENDRUST® RCP150 Rust Converter, Primer & Sealer before applying UB302B.

Apply two to three coats, allowing each coat to become tack dry before recoating. Avoid excessive film build in a single pass.

Care must be taken around exhaust systems, braking surfaces, sensors and other components that must remain free of coating.

Refer to the current Technical Data Sheet and Endrust Work Instructions for complete application guidance.

Professional Endrust Rustproofing

UB302B forms the foundation of Endrust’s heavy-duty bituminous underbody protection systems, providing a proven combination of corrosion resistance, flexibility, seam penetration and sound-deadening performance.

It is particularly suitable for vehicles operating in harsh Australian road, coastal, agricultural and mining environments.

Q: Does Endrust UB302B contain a rust converter?
A: Yes. Endrust UB302B contains rust-converting and corrosion-inhibiting components. This means it can be applied directly over properly prepared light surface rust without requiring a separate rust converter or primer.

Where a vehicle has more significant existing rust, additional preparation and treatment with Endrust RCP150 Rust Converter, Primer & Sealer may be recommended before UB302B is applied.

Q: Can UB302B be applied to a vehicle that already has some rust?
A: Yes. Light surface rust is quite common, particularly on older vehicles, and UB302B is specifically suited to protecting these surfaces.

If more extensive rust is present, the condition is assessed first and additional preparation may be required before rustproofing. Rustproofing protects against further corrosion but is not a substitute for repairing metal that has already been seriously weakened by rust.

Q: Why choose a bituminous underbody rustproofing coating?
A: A quality bituminous coating such as UB302B provides a tough, flexible and water-resistant barrier between the vehicle underbody and the environment.

It is particularly well suited to areas exposed to water, mud, sand, salt, stones and road debris and remains flexible rather than forming a hard, brittle coating.

Q: Will UB302B protect against stone chips and road debris?
A: Yes. UB302B forms a durable, flexible coating that provides excellent protection against normal stone impact, abrasion and road debris.

Vehicles regularly driven on gravel roads, beaches or off-road can experience greater wear in high-impact areas, so occasional inspection and touch-up may be beneficial.

Q: Does UB302B help reduce road noise?
A: Yes. The heavy-bodied coating also provides sound-deadening properties, helping to reduce road noise and vibration transmitted through the vehicle floor and wheel arch areas.

Q: What parts of my vehicle can be protected with UB302B?
A: UB302B is designed primarily for the vehicle underbody and is commonly used to protect areas such as chassis rails, cross-members, floor pans, wheel arches and other exposed underbody steelwork.

A professional applicator will determine which areas should be coated and which components need to remain coating-free.

Q: Is UB302B suitable for 4WDs and vehicles used on beaches or off-road?
A: Yes. UB302B is particularly well suited to 4WDs, work vehicles and vehicles regularly exposed to coastal conditions, beaches, gravel roads, mud and off-road environments.

Its combination of corrosion protection, flexibility and resistance to stone impact makes it ideal for demanding underbody applications.

Q: How long does UB302B last?
A: When correctly applied to a properly prepared surface, UB302B provides long-term underbody corrosion protection.

The condition of any underbody coating will depend on how the vehicle is used. Vehicles subjected to frequent gravel, beach or off-road driving may experience localised wear or chipping over time, which can be easily inspected and touched up when required.