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Chassis Shield™ Underbody Sealant
The underbody seal that changed 4WD care forever. Salt, sand & mud rinse straight off: spray on, let it bond & hit the tracks!
- Extreme hydrophobic & Sand-phobic properties: mud & clay just fall off
- 100% transparent film: see your chassis, no oily sticky mess
- Up to 12 MONTHS of protection (PRO)
- Made for underbodies: chassis, suspension, tow bars, diffs, bullbars & arches
- Cheap resale insurance: a rusty underbody can knock thousands off any 4WD
- Made, bottled, engineered & tested in QLD, Australia
or 4 payments of $9.72 interest-free
- Same-day dispatch on orders before 11am AEST, Monday to Friday
- Free shipping over $200 · express 1-3 business days available
- Click & Collect Brisbane · ready in around 2 hours at Geebung HQ
Quick answers
← swipe the questions →
350,000+Litres sold
70,000+Aussie 4WDers
4.8 ★4,800+ reviews
QLDMade & tested
See the difference
One scratch is all rust needs
Rock rash & stone chips crack open your chassis paint on every trip. Broken chipped paint is all salt water needs to reach bare metal... So we gouged two painted steel plates & let 30 days of corrosive water do its worst!
1
The setupTwo painted steel plates, both gouged. ✗ stays bare, ✓ is sealed with Chassis Shield.= rock rash on your rails
2
The abuseBoth submerged in salt water, then left outside for 30 days straight.= a beach run, then a month in the driveway
3
The result✗ is eaten alive by rust. ✓ is still glossy & rust free.= your next look underneath
30-day salt exposure timelapse
Pick your protection
Original or PRO? Here’s the honest difference.
Same QLD-engineered, sand-phobic transparent film, two strengths. Original is the trip seal you spray before each run; PRO is the same blend on steroids, protecting for up to 12 months.
| Side by side |  Original |  PRO |
|---|---|---|
| Best for | Before every trip | Set & forget |
| Beach protection (salt & sand blasting) | 2 weeks | 3 months |
| Protection window | 6+ months on-road | Up to 12 MONTHS |
| Bare steel | Painted & lined surfaces | ✓ Handles bare steel too |
| Finish | Transparent film | Hard-drying ULTRA gloss |
| Touch dry | 24-48h bond | 4 hours (24h bond) |
| Removal | Easily, with Salt Exterminator | Wears down, then re-coat |
| Sizes | 1L to 20L | 1L to 20L |
| Cost per coat (5L) | ~$7 | ~$14.33 |
| From | $38.90 | $79.90 |
The one that changed 4WD care
The original underbody seal. Copied by many, matched by none.
Chassis Shield was born on the job. Justin, founder, was detailing 4WDs 24/7 with pre-trip protection part of the service, so every blend was designed & proven in the real world on customer rigs first. No copy cat can say that.
In 2021 it changed the 4WD care market forever & every copy cat rust spray since has borrowed its claims from this bottle. We bench test them all: theirs never dry, sitting wet & tacky and grabbing the very sand they claim to repel. Ours repel everything. Customers who've tried the rest put it best: they don't compare durability wise.
| The difference | Chassis Shield | Copy cat rust sprays |
|---|---|---|
| Finish once applied | Clear gloss, never oily or sticky | Never dries: wet & tacky |
| What sticks to it | Nothing: sand & salt rinse off | Soft sticky film grabs sand & dust |
| Protection window | Your choice: trip seal to 12-MONTH season seal | Big label promises, same wet film underneath |
| Sizes & value | 1L to 20L · from ~$6.50 a coat | Small bottles only |
| Track record | The original · 70,000+ 4WDers | New labels, borrowed claims |
The old school fixes
Lano glues sand on. Bitumen hides the rust.
Before Chassis Shield you had two choices: coat it in something sticky, or paint it black & hope. Both hide what's happening to your chassis.
| Old vs new | Chassis Shield | Lano & fish oil | Bitumen rust proofing |
|---|---|---|---|
| Sand & salt on the beach | Repels it, rinses off with water | Glues it to your chassis | A bit tacky: sand sticks more than factory paint |
| Can you SEE your chassis? | 100% transparent gloss | Brown sandpaper effect | Solid black: rust spreads unseen |
| Appearance | Matte factory black turns high gloss | Sticky, dusty film | Flat black, permanent |
| DIY in the driveway | Spray on, done | Messy but yes | Workshop job, $800-$1,200 |
| If damage ever starts | You see it early & treat it | Hidden under residue | Hidden until it's bad |
| When you sell | Torch test passed: clean, glossy chassis | Sticky film is a hard sell | Buyers assume it's hiding something |
Chassis Shield is made to apply OVER existing aftermarket lining too, adding sacrificial gloss protection to a rustproofed rig.
Trusted by the 4WD community
The gear the 4WD 24-7 crew runs on their own rigs
The crew from 4WD 24-7, the biggest 4WD channel in the world with over a billion minutes watched, run 4WDetail on their own rigs. Watch Chassis Shield get put up against salt water, fish oil & real pre-trip prep below!
Chassis Shield PRO · “vs salt water test”
Graham Cahill · 4WD 24-7 · “tests the NEW Chassis Shield PRO”
Chassis Shield PRO · “vs old school protection”
Pre-trip protection · “Do NOT go on your next trip without applying this first!”
← swipe the clips →
Got footage of mud falling off your sealed chassis? Send it to help@4wdetail.com. Best clip each month gets a free 5L.
Why underbodies rust after washing
Think hosing underneath is enough? Unfortunately not...
There's a variety of different salt compounds in the ocean. Some wash away with water & some do NOT. These water insoluble compounds are called Ionic Salt compounds & their structure cannot be broken up with just water! They sit in your chassis rails, seams & bolt threads, drawing in moisture & corroding your 4WD from the inside out. That's why almost every beach-driven 4WD has some degree of surface rust!
The old fixes all share one flaw: you can't see what's happening underneath them. Lanolin & fish oil bury your chassis under a sticky brown film that grabs every grain of sand. Bitumen & rubberised rustproofing paint it black: tough at first, but once it chips, moisture wicks underneath & rust spreads where you'll never spot it.
And rust doesn't just cost repairs, it butchers resale. Used-car valuation guides put the discount for rust at 10-20% of the price, 20% or more once it reaches the chassis: on a $60,000 tourer that can be $6,000 to $12,000 gone. Used-4WD buying guides tell buyers to crawl underneath with a torch before paying a cent, & rusty, mud-packed rails kill the deal on the spot.
Sources: Motorway, “How does rust affect car value?” (2026) · Club 4X4, “Your Guide to Buying a Used 4WD” (2025)
That's exactly why we engineered Chassis Shield as a 100% transparent gloss film: it physically blocks corrosive ionic salts & acidic mud, repels the sand that blasts your underbody on the beach & still lets you inspect your actual chassis at every wash!
Protection you can see through is protection you can trust!
Clear physical barrier
A transparent film between your chassis & the corrosive ionic salts & acidic mud.
A transparent film between your chassis & the corrosive ionic salts & acidic mud.
Hydrophobic & sand-phobic
Salt water beads off & beach sand won't bond, so it rinses away with just water.
Salt water beads off & beach sand won't bond, so it rinses away with just water.
Ultra gloss you can inspect
Rejuvenates the chassis to showroom condition & keeps it visible at every wash.
Rejuvenates the chassis to showroom condition & keeps it visible at every wash.
100% transparent · Made, bottled & tested in QLD
How to use it
The pro detailing tried & tested method
1
Wash & dry
Salt Exterminator the underbody & topside, pressure rinse, then let it dry. You're sealing a clean, dry chassis, never sealing salt in.
2
Spray & leave
Coat chassis, wheels, axles, sliders & arches. DO NOT rinse off after application. The film IS the protection.
3
Bond & go
PRO: touch dry in 4 hours, bond 24 hours, extra THIN coats 12 hours apart. Original: bond 24-48 hours before the trip.
← swipe the steps →
THE GOLDEN RULES
Apply to: clean, DRY underbody · paint, lining or bare steel (PRO)
Leave uncoated: rubber bushes & joints · engine · exhaust · shock shafts
Never: rinse off after applying
Before a trip: allow 24h (PRO) or 24-48h (Original) to bond
Layering (PRO): thin coats, 12 hours apart in low humidity
After the trip: rinse with water; mud gets a Salt Exterminator soak
Fresh start (Original): removes easily with Salt Exterminator
30-Day Guarantee
Use it as directed before your next trip. If you’re not happy with the results, email us within 30 days and we’ll refund your bottle in full*.
350,000+Litres sold
70,000+Aussie 4WDers
★★★★★ 4,800+ Reviews
*The fine print (it’s short)
First purchase of Chassis Shield or Chassis Shield PRO, sizes up to 5L. One claim per customer, household and delivery address. Use as directed. Email help@4wdetail.com within 30 days of delivery with your order number and a quick note on how you used it (surface, coats and bond time; a photo helps). We'll try to make it right first. If we can't get you the result, the full product price is refunded within 5 business days. Original shipping not refunded. 20L trade drums excluded. AU & NZ orders. Claims we reasonably believe are fraudulent may be declined. In addition to your Australian Consumer Law rights.
FAQ
Your questions, answered
Thousands of real 4WDers. Here’s what they reckon.
✦ WHAT REVIEWERS SAY
Reviewers consistently say the dirt just falls off: red clay rinsed away 150km later without a wash, barely any mud stuck after bog runs, & the chassis comes up like new after K'gari, the High Country, bush tracks & saturated farm paddocks alike. PRO users call out the hard, dry finish with zero oily residue & the gloss holding for months, & those who've tried other brands say they don't compare durability wise. A handful note the included trigger bottle can play up, so keep a spare quality trigger handy.
Summarised from verified Loox reviews of Chassis Shield Original & PRO
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