Professional Dinitrol Underbody Protection

Protect Your Vehicle From Corrosion – Properly.

At Shropshire Mechanical Services, we specialise extensively in professional vehicle underbody protection and corrosion prevention.

We are proud to be the Midlands’ Dinitrol Approved Application Centre, using market-leading Dinitrol corrosion-prevention products and approved application processes.

Being a Dinitrol Approved Application Centre isn’t simply about the products we use. Our preparation standards, processes and application methods are carried out to meet Dinitrol’s strict requirements.

Our comprehensive treatment takes two full days, with the first day dedicated almost entirely to preparation.

Our Two-Day Underbody Protection Process

We believe the quality of any corrosion-protection treatment is determined by what happens before the final coating is applied.

That’s why we don’t simply spray underseal over the underside of your vehicle. Here is an example of why the full 2 days are needed, and why to steer clear of people / businesses claiming they can do it on your drive for a few hundred quid!

Every vehicle goes through an extensive preparation and treatment process designed to protect both the areas you can see and the internal sections you can’t.

Day 1 – Strip Down & Preparation

Vehicle Strip Down

The first day begins by removing the relevant components required to properly access the vehicle’s underside.

Depending on the vehicle, this can include:

Wheels
Wheel-arch liners
Undertrays
Heat shields
Other removable components restricting access

Removing these components allows us to expose and inspect areas that are normally hidden and would otherwise be extremely difficult to treat correctly.

Rust & Surface Preparation

Once the underside is exposed, preparation begins.

We primarily use hand tools to carefully remove:

Loose surface rust
Flaking paint
Failed or loose existing coatings
Dirt and debris
Other surface contamination

Using hand tools gives us greater control and allows us to take a careful, non-abrasive approach rather than unnecessarily attacking the underside with aggressive power tools.

Where certain areas require more intensive treatment, bead blasting can be used selectively.

Our aim is to remove loose corrosion and contamination while retaining sound factory coatings wherever appropriate.

Dinitrol ML Cavity Injection – Before Any Water Is Introduced

Before the underside is steam cleaned, we carry out the Dinitrol ML cavity treatment.

Dinitrol ML is injected into chassis rails, subframes, box sections and other internal cavities to protect areas that cannot be reached externally.

Importantly, we carry out this stage before steam cleaning.

Dinitrol ML has excellent water-repellent and penetrating properties, so treating the internal sections first ensures they are protected before we introduce any water to the vehicle during the cleaning process.

The product penetrates seams, joints and difficult-to-access areas, helping to displace moisture and providing protection against corrosion from within.

This means we’re not simply protecting the visible underside of your vehicle – we’re treating corrosion-prone areas from the inside out.

Steam Cleaning

Only once the internal cavities have been treated with Dinitrol ML do we move on to steam cleaning.

The exposed underside is thoroughly steam cleaned to remove remaining:

Dirt
Rust deposits
Road salts
Grease
Dust
Surface contamination

Once cleaning is complete, the vehicle is left to dry overnight.

This allows as much residual moisture as possible to drain and evaporate naturally before we begin the second stage of the treatment.

Day 2 – Drying, Masking & Protection

Thorough Drying

We don’t rely on overnight drying alone.

On Day 2, the vehicle’s underside is thoroughly dried using our high-powered blower system.

Particular attention is paid to seams, cavities, joints and other areas where moisture can remain trapped.

We don’t begin applying the external protective coatings until we’re satisfied that the vehicle is properly dry.

Careful Masking

Before any Dinitrol products are applied to the exterior underside, areas that should remain free from coating are carefully and individually masked off.

This includes:

Brake lines
Brake discs and braking components
Exhaust sections
Rubber components where appropriate
Electrical connections and sensitive components
Other areas that should not receive the underbody coating

We specifically mask the brake lines rather than simply coating over them, helping to keep them visible for future inspection, servicing and condition checks.

Taking the time to mask these areas properly is another important part of our preparation process. It provides a much cleaner and more professional finished result while ensuring components that need to remain accessible and visible are protected from overspray.

Dinitrol RC900 – Rust Conversion

Where deeper corrosion remains but has not compromised the structural integrity of the vehicle, affected areas can be treated using Dinitrol RC900.

RC900 is a penetrating rust converter designed to react with existing corrosion and convert it into a stable protective surface.

It penetrates the rust and forms a protective lacquer, preparing the affected area for the next stage of corrosion protection.

It’s important to understand that rust converter isn’t a substitute for proper preparation.

Loose and flaking corrosion is removed first. RC900 is used specifically where appropriate as part of the overall treatment process.

Dinitrol 4941 – Long-Term Underbody Protection

Once preparation, drying, masking and any required rust conversion are complete, we apply Dinitrol 4941 across the vehicle’s underside.

Dinitrol 4941 is a tough, flexible and self-healing underbody wax designed to provide long-term protection against:

Water
Moisture
Road salt
Dirt
Winter road conditions
Stone impact
Further corrosion

Unlike hard coatings that can potentially crack and allow moisture to creep underneath, the wax-based protection remains flexible and has self-healing properties.

The result is a durable protective barrier designed specifically for the harsh environment underneath a vehicle.

Reassembly & Final Inspection

Once the Dinitrol application has been completed, all masking is carefully removed.

The components removed during preparation are then refitted, including arch liners, undertrays, heat shields, wheels and other relevant components.

The finished vehicle is inspected before leaving the workshop.

Final Exterior Wash

We don’t want you collecting a vehicle covered in residue from the preparation process.

Once the treatment and reassembly are complete, the vehicle receives a full exterior wash to remove any remaining dust, rust deposits or workshop residue.

Your vehicle leaves us protected underneath and presentable above.

We Don’t Simply Underseal Cars

There is a significant difference between spraying underseal onto a vehicle and carrying out a professional corrosion-prevention treatment.

Applying a coating over dirt, moisture, loose rust or deteriorating existing coatings can simply hide corrosion rather than properly address it.

In some circumstances, poor preparation can even trap moisture behind a coating.

That’s why so much of our two-day process is dedicated to preparation.

Preparation is the most important part of the job.

The final Dinitrol coating may be what you see, but it’s the work underneath it that determines the quality of the finished treatment.

See Exactly What We’ve Done to Your Vehicle

One of the difficulties with underbody protection is that much of the work disappears once the vehicle has been reassembled.

We believe you should be able to see exactly what you’ve paid for.

That’s why we document the treatment extensively.

Full Treatment Timelapse

Throughout the process, a tripod-mounted camera takes a photograph approximately every 10 seconds.

These images are combined to produce a complete timelapse of the treatment.

You can see the strip down, preparation, treatment and reassembly taking place rather than simply dropping off your vehicle and being presented with a freshly coated underside two days later.

Before & After Photos and Videos

We also take comprehensive before-and-after photographs and videos documenting the condition of your vehicle and the transformation throughout the treatment.

This provides a useful record of areas that will become hidden again once undertrays, arch liners and other components are refitted.

4-Year Written Guarantee

We’re confident in our preparation, products and application process, which is why our treatment comes with a:

4-Year Written & Signed Guarantee

But our involvement doesn’t simply end when you collect your vehicle.

Your treatment also includes a:

FREE Annual Underbody Inspection

We recommend returning the vehicle to us each year so that we can inspect the condition of the treatment and identify any areas that may require attention.

Vehicles operate in an extremely harsh environment underneath, and annual inspections allow us to ensure the protection continues performing as intended.

What’s Included?

Our comprehensive Dinitrol underbody protection treatment includes:

Two full days in our workshop
Vehicle strip down
Removal of relevant undertrays, arch liners and heat shields
Detailed underbody inspection
Extensive manual rust and surface preparation
Selective bead blasting where required
Dinitrol ML internal cavity and chassis-rail injection
Steam cleaning
Overnight drying
High-powered blower drying
Careful masking of brake lines, braking components, exhaust sections and other sensitive areas
Dinitrol RC900 rust conversion where required
Dinitrol 4941 underbody wax protection
All Dinitrol products and consumables
Complete vehicle reassembly
Final inspection
Exterior vehicle wash
Before-and-after photographs and videos
Full treatment timelapse
Written and signed 4-year guarantee
Free annual inspections

Pricing – POA

Every vehicle is different, and the amount of preparation required can vary considerably depending on its size, age, design and existing condition.

For this reason, our Dinitrol underbody protection treatments are individually priced – Price on Application (POA).

For an accurate quotation, simply contact us with your vehicle registration, make and model.

We’ll then be able to discuss your vehicle and provide you with a quotation for the complete treatment.

Booking Your Vehicle

Our comprehensive treatment occupies one of our workshop ramps for two full days, so a 50% deposit is required to secure your booking.

The remaining balance is payable upon completion of the treatment and collection of your vehicle.

Once your booking and deposit have been confirmed, we’ll send you your booking confirmation, directions to our workshop and everything you need to know before bringing your vehicle to us.

Complimentary Courtesy Car

We understand that being without your vehicle for two days can be inconvenient.

That’s why a complimentary courtesy car can be provided where required, subject to availability.

There is no charge for the use of the courtesy car. However, customers are responsible for arranging their own temporary comprehensive insurance cover for the duration of the loan.

Alternatively, if you would prefer us to arrange the required cover, we can do this for an additional £45.

Courtesy cars should be requested when booking and are subject to availability, so we recommend letting us know as early as possible if you require one.

Local Transport

If you don’t require a courtesy car, we can also help with local transport where arranged in advance.

Where possible, we can provide transport home locally or take you to nearby bus or railway connections, including Shrewsbury or Telford.

Our aim is to make leaving your vehicle with us for its two-day treatment as straightforward and convenient as possible.

Is Underbody Protection Worth It?

If you’re planning to keep your vehicle, professional corrosion protection can be one of the most worthwhile preventative treatments you carry out.

It’s particularly suitable for:

4x4s and off-road vehicles
Pick-ups
Vans and commercial vehicles
Campervans
Motorhomes
Classic and cherished vehicles
Japanese imports
Older vehicles worth preserving
Newer vehicles you intend to keep long-term
Vehicles regularly exposed to winter roads and road salt

Corrosion doesn’t improve with time.

Treating a vehicle while its structure is still sound can help prevent relatively minor corrosion from developing into expensive repairs later in its life.

Why Choose Shropshire Mechanical Services?

When you leave your vehicle with us, you’re not paying for somebody to simply spray the underside black.

You’re paying for the preparation, experience, products, application process and attention to detail behind the finished result.

With our treatment you receive:

✓ Midlands Dinitrol Approved Application Centre

✓ Genuine Dinitrol corrosion-prevention products

✓ Comprehensive two-day treatment

✓ Extensive strip down and preparation

✓ Internal cavity protection before steam cleaning

✓ Selective bead blasting where required

✓ Brake lines and sensitive components carefully masked rather than coated over

✓ Rust conversion where appropriate

✓ Professional Dinitrol underbody wax application

✓ Complete photographic and video documentation

✓ Full treatment timelapse

✓ Written 4-year guarantee

✓ FREE annual inspections

✓ Complimentary courtesy car when required – subject to availability

Protect It Today. Preserve It for Tomorrow.

Whether it’s your daily vehicle, workhorse, 4×4, campervan or something you simply plan to keep for many years, the best time to deal with corrosion is before it becomes a structural problem.

Give your vehicle the protection it deserves with a comprehensive Dinitrol corrosion-prevention treatment from Shropshire Mechanical Services.