MOT Fail Or Fixable? Quick Answer
Imagine you find a fresh chip on the morning of your MOT — a commuter’s nightmare. In our experience most small chips are repairable if you act quickly. Damage in Zone A (the vertical strip in front of the driver) over 10mm will usually fail. Elsewhere in the wiper‑swept area, anything over 40mm is likely a fail. Outside the swept area, light marks are often acceptable so long as they don’t affect vision.
This guide is for drivers in Essex, Hertfordshire and North Essex who need a clear decision before an MOT. You’ll learn the size limits, quick checks to do, what repairs can save your test and when replacement — and ADAS calibration — is the right choice. If you’re in doubt, call Jay & Robs for a fast, practical assessment.
MOT Windscreen Zones Explained With Limits
Zone A is a 290mm wide vertical strip centred on the steering wheel and inside the wiper‑swept area. Chips or cracks over 10mm here usually fail the MOT. The rest of the swept area (Zone B) has a 40mm limit. Marks outside the swept area or in the top tinted band are normally acceptable unless they obstruct view.
A common issue we see is people underestimating size — 10mm is about a pencil eraser; 40mm is roughly two £2 coins side‑by‑side. Photograph damage with a coin for scale and use our windscreens repair page to check options.
Real‑World Examples: Will It Pass Or Fail?
- Small chip in Zone A (8–10mm): borderline — repair quickly.
- 12mm bullseye in Zone A: likely fail; replacement may be required.
- 40mm crack in the swept area: typically a fail and often replacement.
- Short crack outside the swept area: usually passes if visibility is unaffected.
- Two chips within 10cm: testers may treat them as a single damaged area.
- Chip at the screen edge with radiating cracks: high risk of fail due to strength loss.
Delay makes matters worse: vibration and weather can turn a repairable chip into an MOT‑failing crack. See our windscreen crack progression advice for more detail.
This image was generated with AI and may not always represent the product or service exactly.
Instant MOT Fails To Watch For
- Damage over 10mm in Zone A or over 40mm in the swept area.
- Long cracks, especially those reaching the glass edge.
- Chips with radiating cracks in the driver’s direct view.
- Obstructions (sat navs, stickers, permits) within Zone A.
- Heavy wiper scratches that materially restrict vision.
If you must travel, only go to a pre‑booked MOT or repair and only if it’s safe. If you’re unsure whether driving is legal, check our guidance on driving with a cracked windscreen.
When A Same‑Day Repair Can Save Your Test
Resin repair is often quick and effective. We clean the chip, remove air, inject optically clear resin, UV cure and polish — typically 20–30 minutes. In our experience this restores strength and clarity enough to pass most MOTs when the damage is within limits.
Call before your MOT or immediately after a fail to meet retest windows. We commonly provide same‑day visits across Essex and Hertfordshire. Repairs are unsuitable if the damage is at the very edge, through the laminate, or intrudes on ADAS camera zones.
Repair Or Replace: How To Decide
We prioritise repair when safe and within size limits because it’s cheaper and quicker and preserves the original glass. Replace the screen if the crack is long, at the edge, crosses the driver’s view or affects ADAS cameras or sensors.
For replacements we use correct bonding procedures and observe cure times. Many modern cars require ADAS calibration after a screen change; Jay & Robs handles both static and dynamic calibration methods to keep safety systems accurate.
What Most People Get Wrong
Most drivers assume a small chip “won’t spread” — but vibrations and temperature changes often make cracks grow fast. Acting within days, not weeks, keeps repair options open.
When This Doesn’t Apply
If the vehicle is used commercially with frequent long journeys or carries critical ADAS-dependent safety loads, replacement and professional calibration are often the safest choice even for smaller damage.
Costs, Insurance And Warranties
We’re insurer‑approved and assist with paperwork. Many policies cover chip repair with little or no excess; replacements usually carry an excess. Repairs generally don’t affect no‑claims — always confirm with your insurer first.
All work from Jay & Robs carries our lifetime workmanship warranty while you own the vehicle. Removed glass is recycled responsibly.
This image was generated with AI and may not always represent the product or service exactly.
Step‑By‑Step: What To Do Now
- Photograph the damage with a £1 coin for scale, inside and out.
- Note your vehicle make, model, year and any rain sensors or cameras.
- Contact Jay & Robs for a quick quote and to book our mobile service in Essex or Hertfordshire.
- Park on level ground and, if possible, provide shelter in poor weather before our arrival.
We commonly cover Bishop’s Stortford, Harlow and surrounding North Essex and Herts towns, often with same‑day slots.
Quick Checklist
- Photo with coin for scale
- Check Zone A vs swept area
- Call Jay & Robs for same‑day options
- Don’t drive unless it’s safe or pre‑booked
FAQs: Practical Answers To Help You Decide
Should I drive to the MOT if my screen has a chip?
You can drive to a pre‑booked MOT or repair only if the chip hasn’t worsened and visibility is safe. If the damage is near Zone A or the edge, call us first — in our experience it’s safer to arrange collection or a mobile repair.
Will a resin repair affect MOT results?
A professional resin repair that restores clarity and keeps damage within legal size limits normally passes the MOT. Provide photos to your tester if needed and keep the repair receipt.
How urgent is ADAS calibration after replacement?
Very. If your vehicle uses lane‑keep, adaptive cruise or automatic braking, calibration is required to maintain system accuracy. We offer both static and dynamic calibration services as part of replacements.
What information should I have when I call you?
Have your vehicle make, model, year and a description of any sensors or camera locations. Send photos with a coin for scale to speed up an accurate quote and booking.
Do you cover insurance claims for windscreen work?
Yes. We’re insurer‑approved and will help with the paperwork so you can use your policy for repairs or replacements where applicable.
Why Choose Jay & Robs
Local, mobile and practical across Essex, Hertfordshire and North Essex. We aim for same‑day visits for MOT‑threatening chips and deliver honest advice, quality glass, ADAS‑ready replacements and a lifetime workmanship warranty.
For repair or replacement options see our windscreen repairs page, our mobile windscreen fitters details, the areas we cover, our cracked windscreen safety guide, windscreen crack progression notes, ADAS calibration guide, and advice on whether it’s illegal to drive with a cracked windscreen.