The HQ, HJ, HX, HZ and WB Holden range remains one of the most popular families of the Australian classic car market. From Kingswoods and Premiers to Sandmans, One Tonners, Statesmans and WB utilities, these vehicles have become highly sought after by collectors, restorers and enthusiasts alike.

The problem is that many of these cars are now more than 40 to 50 years old. While mechanical components are generally straightforward and relatively inexpensive to repair, rust, poor restorations and hidden structural issues can turn what looks like a bargain into a financial disaster.

A careful inspection before purchase can save thousands of dollars and months of frustration.

Start with the Body and Rust

Rust is the number one issue affecting HQ-WB Holdens.

Many cars look fantastic in photographs but hide significant corrosion beneath fresh paint and body filler.

Always inspect the body thoroughly before worrying about the engine or transmission.

Check the Windscreen and Rear Window Channels

These are among the most expensive rust repairs on HQ-WB Holdens.

What to Look For

• Bubbling paint around window rubbers
• Rust staining
• Cracked sealant
• Water leaks

Rust often develops underneath the rubber seal and remains hidden until the glass is removed.

If corrosion is visible externally, there is usually significantly more underneath.

Inspect the Plenum Chamber

The plenum chamber below the windscreen is a notorious rust trap.

Symptoms

• Water leaks into cabin
• Damp carpets
• Rust visible through vent openings

Repairs here can be labour intensive and costly.

Examine the Sills

Sills are structural and critical to vehicle integrity.

What to Check

• Bubbling paint
• Swollen seams
• Fresh underbody coating
• Crunching sounds when pressed

Fresh paint on the lower body should always raise questions.

Check the Floor Pans

Lift carpets wherever possible.

Look For

• Surface rust
• Previous patch repairs
• Damp insulation
• Fresh seam sealer

Water leaks from windows and door seals often cause floor corrosion.

Inspect the Boot Floor

The spare wheel well and boot floor are common problem areas.

Signs of Trouble

• Rust under mats
• Water pooling
• Fresh paint only in boot area
• Poorly welded repairs

Boot rust is often linked to rear window seal failure.

Examine the Chassis Rails

Although generally strong, HQ-WB chassis sections can rust internally.

Check For

• Rust scale
• Flaking metal
• Fresh black underbody paint
• Poor previous repairs

Never assume a freshly painted chassis is rust-free.

Inspect the Doors

Door repairs can become expensive.

Common Problems

• Rust along lower edges
• Swollen seams
• Blocked drain holes
• Bubbling paint

Open each door and inspect carefully from underneath.

Verify Panel Alignment

Poor panel fit often indicates accident damage or previous rust repairs.

Check

• Door gaps
• Guard alignment
• Bonnet fitment
• Boot or tailgate alignment

Factory panel gaps were not perfect, but significant inconsistencies are worth investigating.

Engine Inspection

Most HQ-WB Holdens were fitted with Holden six-cylinder or V8 engines.

The good news is that mechanical issues are generally cheaper to repair than body problems.

Check for Oil Leaks

Common Leak Areas

• Rocker cover
• Timing cover
• Sump
• Rear main seal

Minor sweating is normal.

Heavy oil leaks suggest maintenance has been neglected.

Inspect Cooling System Condition

Overheating can cause major engine damage.

Look For

• Coolant stains
• Rusty coolant
• Damaged hoses
• Overflow residue

Cooling system neglect is extremely common in older Holdens.

Listen for Engine Noise

Potential Problems

• Timing chain rattle
• Bottom-end knock
• Excessive valve train noise
• Exhaust leaks

A healthy Holden six or V8 should run smoothly without major mechanical noises.

Transmission Inspection

Most HQ-WB Holdens were fitted with:

• Trimatic automatics
• Turbo 400 automatics (some V8s)
• Manual transmissions

Automatic Transmission Checks

Symptoms to Watch For

• Delayed engagement
• Slipping between gears
• Harsh shifts
• Burnt transmission fluid smell

Drive the vehicle if possible and ensure every gear operates correctly.

Steering System Inspection

HQ-WB Holdens use recirculating ball steering systems.

Common Problems

• Excessive steering play
• Wandering at speed
• Worn linkage components
• Leaking steering box

A small amount of play is normal.

Large amounts suggest repairs are needed.

Suspension Inspection

Many original suspension components are now worn out.

Check For

• Sagging ride height
• Uneven tyre wear
• Clunks over bumps
• Worn bushes

Suspension rebuilds are relatively straightforward but should still factor into purchase price.

Electrical System Inspection

Electrical faults are common due to age.

Test

• Headlights
• Indicators
• Brake lights
• Wipers
• Heater fan
• Gauges

Many electrical issues are minor but can indicate poor previous maintenance.

Best Rust Detection Product

Recommended Product: Strong Rare Earth Magnet

Benefits

• Detects body filler
• Identifies hidden repairs
• Quick and inexpensive

Best For

• Panel inspections
• Verifying restoration quality

Verify Identification Numbers

Always confirm:

• Chassis number
• Engine number
• Compliance plate details

Check that the numbers align with the seller’s description.

This is particularly important for:

• Monaros
• Sandmans
• GTS models
• Statesmans

These vehicles attract significant premiums and are occasionally misrepresented.

Inspect Previous Restoration Work

Not all restorations are equal.

Warning Signs

• Excessive body filler
• Overspray
• Uneven welds
• Mismatched paint finishes

A poor restoration can be more problematic than an honest original car.

Best Rust Prevention Product

Recommended Product: Lanox MX4 Lanolin Spray

Benefits

• Long-term corrosion protection
• Penetrates seams and cavities
• Ideal for classic Holdens

Best For

• Newly purchased vehicles
• Rust prevention maintenance
• Ongoing preservation

Red Flags That Should Make You Walk Away

Consider walking away if you find:

• Severe plenum rust
• Extensive chassis corrosion
• Poor structural repairs
• Missing identification numbers
• Multiple hidden rust areas
• Significant accident damage

Mechanical problems are generally repairable.

Major rust repairs are where budgets quickly disappear.

Recommended Inspection Kit

Before viewing a vehicle, take:

• Digital borescope
• Inspection magnet
• LED torch
• Clean rag
• Tyre pressure gauge
• Notebook or smartphone

A small investment in inspection tools can save thousands of dollars later.

Buying a HQ, HJ, HX, HZ or WB Holden can be one of the most rewarding experiences for an Australian car enthusiast. These cars remain relatively simple to maintain, parts support is excellent, and values continue to remain strong for quality examples.

However, rust remains the single biggest threat to these vehicles. A mechanically tired car can usually be repaired without excessive cost, but extensive corrosion can easily exceed the value of the vehicle.

The smartest buyers focus on body condition first, structural integrity second and mechanical condition third. Engines, transmissions and suspension can all be rebuilt. Finding a rust-free body is becoming increasingly difficult.

Take your time, inspect carefully, and remember that the cheapest car is rarely the cheapest Holden to own.

Related Articles

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• Best Rust Prevention Products for Classic Holdens