Axle springer

I would like to raise a very serious issue over the safety of coil springs Last week, I was driving home from work at about 4 pm in my 46,000 mile 2004 reg car. I had gone about 1 mile (almost entirely dual-carriageway, speed limit 40 mph, but traffic doing about 35 mph in fairly heavy rain) when <> the front O/S tyre blew out. Luckily I was able to keep control. I fitted the 'space saver' spare and continued about 6 mikes to my local 'Kwik-fit'. They duly fitted a new tyre to the original wheel (while I drove 1/2 mile home to collect my credit card). On my return they removed the 'space saver' to fit the original wheel with its new tyre. But the fitter noticed that the suspension coil spring was broken in two. Moreover, it was obvious from marks in the tyre that the broken coil had CAUSED the blow-out by digging into the inner wall. 'Kwik-fit' were as horrified as I was. I have retained the broken spring and tyre. It is therefore my contention that the blow-out was the obvious, direct and immediate result of the coil spring failure. That major suspension components can fail at this mileage on a modern car is bad enough, but for a broken spring to cause a tyre blowout is a shocking design flaw. 'Kwik-fit' recommended that both front springs be replaced as a precaution. There is a tendency to blame this on 'speed bumps'. They obviously don't help (and I avoid them like the plague and take them slowly), Car makers should make their products 'fit for purpose' - and that includes reasonable driving over obstacles places in the road by local authorities.

Asked on 18 April 2009 by

Answered by Honest John

I have covered this about 500 times in e-mails and it has appeared about 10 times in my columns. These failures of European made coil springs fitted to all European makes and models for the past 10 years are extremely common. BMWs and Mercedes as well as Citroens, Peugeots and Fords. The fault seems to be that the springs are crudely finished off at the ends. To spread forces, a spring around a strut should be tapered or flattened at the ends and a standalone spring should be pigtailed (the end of the spring crossed across the bottom). The problem is compounded by the cups that springs sit in on MacPherson strut suspension as these harbour wet road salt, inducing corrosion at the ends. The corroded springs are then further weakened by the shocks of potholes and speed humps. Interestingly, they usually snap first thing in the morning. Yours is the first case I have read of one snapping at speed in traffic. But I agree, these cheaply finished springs are a cost-cut too much. You should inform www.vosa.gov.uk , and if your local authority has installed humps more than 100mm high, you have grounds to sue for the damage they inflicted on your car.

Tags: suspension technical issues owning