Generations
451 — Second Generation
2007–2014
1.0 MHD
Top issues to watch for
The most serious Smart Fortwo Pulse Mhd problems ranked by severity. We track 5 known issues — here are the ones you need to know about first.
Dangerous
Brake pipe corrosion (451)
The brake pipes on the 451 generation Smart ForTwo are prone to premature corrosion, particularly where they run along the chassis rails and around wheel wells. The small car's low ground clearance increases exposure to road salt and water spray. MOT data shows this model fails brake pipe inspections at 7.8 times the national fleet average, with failures occurring across all mileage bands including very low mileage examples. This is a safety-critical failure that can result in complete brake system failure.
What happens if ignoredCorroded brake pipes can rupture without warning, causing complete loss of braking to one or more wheels. This creates an immediate danger to occupants and other road users. Replacement typically requires multiple sections of brake pipe and professional pressure bleeding of the system. The car should not be driven if brake pipe corrosion is suspected.
Independent garage
£200–£400
Specialist
£250–£500
Main dealer
£400–£700
Parts only
£50–£150
Major
Brake binding (451)
The brake calipers on the 451 Smart ForTwo are prone to seizing, causing the brake pads to remain in contact with the discs even when the brake pedal is released. MOT data shows this model records binding brakes at 7.2 times the national fleet average, particularly affecting cars between 40,000-60,000 miles. The problem is often caused by corrosion of the caliper slide pins or contaminated brake fluid causing the caliper piston to stick.
What happens if ignoredBinding brakes cause excessive brake pad and disc wear, reduced fuel economy, and can lead to brake failure through overheating. The affected brake may fade or fail completely under heavy use. Prompt repair involves caliper overhaul or replacement and brake fluid change. Continued driving risks complete brake component failure.
Independent garage
£150–£300
Specialist
£200–£400
Main dealer
£300–£600
Parts only
£80–£200
Major
Coil spring failure (451)
The coil springs on the 451 Smart ForTwo are prone to fracturing, particularly the front springs. MOT data shows spring failures at 3.2 times the national fleet average, affecting cars with 40,000+ miles. The springs can fracture near the end coils due to corrosion or metal fatigue. A broken spring affects ride height, handling, and can cause tyre damage if the broken end contacts the wheel.
What happens if ignoredA fractured spring reduces ride quality and handling stability. The broken end can damage the tyre sidewall or foul against the wheel rim during suspension movement. In severe cases, a completely collapsed spring can cause loss of vehicle control. Replacement requires both springs on the same axle to maintain balanced handling characteristics.
Independent garage
£200–£350
Specialist
£250–£400
Main dealer
£400–£600
Parts only
£100–£200
Minor
Front suspension bush wear (451)
The front suspension bushes on the 451 Smart ForTwo show accelerated wear, particularly the lower arm bushes and anti-roll bar bushes. MOT data shows suspension component wear at 7.0 times the fleet average for cars with 60,000-80,000 miles. The short wheelbase and urban driving patterns typical of Smart cars place high stress on the suspension components during parking manoeuvres and tight cornering.
What happens if ignoredWorn suspension bushes cause poor handling, uneven tyre wear, and increased road noise. While not immediately dangerous, continued use leads to accelerated wear of other suspension components and tyres. Replacement involves fitting new rubber bushes to the suspension arms, typically requiring specialist tools for pressing.
Independent garage
£200–£350
Specialist
£250–£400
Main dealer
£400–£650
Parts only
£80–£150
1 more known issues tracked
Including wear items, electrical niggles, and generation-specific problems. Check a specific car to see which issues apply to its age and mileage.
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Related
Smart Fortwo Pulse Mhd reliability FAQs
What are the most common problems with the Smart Fortwo Pulse Mhd?
The Smart Fortwo Pulse Mhd has 5 known issues across 3 severity levels. The most serious are: Brake pipe corrosion (451).
Is the Smart Fortwo Pulse Mhd reliable?
The Smart Fortwo Pulse Mhd has 1 dangerous and 2 major known issues. Most can be avoided with a thorough pre-purchase check and full service history.
How much does it cost to fix Smart Fortwo Pulse Mhd problems?
Repair costs range widely. The most significant issue (Brake pipe corrosion (451)) costs £200–£400 at an independent garage. Minor issues can be under £200. Always get a full inspection before buying.