Suspension faults are one of the top three reasons UK cars fail their MOT every year. The good news: most of them are cheap to fix if you catch them early. Here are the faults DVSA testers flag most often and what each one actually means.
1. Excessive shock absorber leak
A light film of oil on a damper body is allowed. A wet, dripping shock with oil running down to the spring is an automatic fail. Replace in pairs (both fronts or both rears) so the car stays balanced.
2. Broken or cracked coil spring
Most snapped springs fail at the bottom coil — corrosion plus pothole impact. A cracked spring is a major defect and an instant MOT fail. Always replace as a pair.
3. Worn top mounts and bearings
Knocking over speed bumps, vague steering return, clunks on full lock — usually a tired top mount. Cheap part, but you have to disassemble the strut to fit it, which is where DIYers get caught out (see our spring compressor guide).
4. Perished bushes
Lower arm bushes, anti-roll bar drop links and rear beam bushes all crack with age. Testers grab them with a pry bar — any visible play is a fail.
5. Excessive corrosion on a strut
If the strut tube is rust-flaked or pitted near the spring seat, it's an advisory at best and a fail if the seat itself is compromised. Common on 10+ year old cars in salt-grit areas of Scotland and the North.
The cheapest way to fix it all in one go
If you've been told two or three of the above, replacing the entire strut assembly is almost always cheaper than fitting individual parts at a garage. A pre-assembled unit replaces the spring, damper, top mount, bearing and bump stop in one bolt-on job — no labour for disassembly, no risk.
Tip: book your retest within 10 working days of the original fail and it's free at most DVSA test centres.