Take the 2-minute tour ×
Motor Vehicle Maintenance & Repair Stack Exchange is a question and answer site for mechanics and DIY enthusiast owners of cars, trucks, and motorcycles. It's 100% free, no registration required.

I just had my car serviced and they discovered that the front, near side coil spring is "incomplete" and needs replacing. I'm getting conflicting advice about whether I need to replace both front springs at the same time, or whether it's OK to just replace the one that's failed.

So - do I need to replace both, or just the one that's failed?

share|improve this question

1 Answer 1

up vote 7 down vote accepted

It is always recommended to replace suspecsion and braking components on both sides of the same axle at the same time, wherever possible.

Both will currently be the same age - if one has failed, it is likely that the other is in a similar condition and so could easily fail soon. In the case of springs, the constant flexing of the metal can eventually lead to fatigue, which is presumably the cause of the first failure - the other spring will be similarly fatigued. Similar arguments apply to other components such as shocks and bushes, which all wear out over time.

Additionally I suspect (although I'm not a metallurgist, so this is just speculation) that the spring rate will change over time and use, so a new spring would be slightly harder than the old one - if that is the case then it would result in uneven handling, which would be very dangerous. This is certainly the case with shock absorbers, which lose their damping ability as they wear - one side well damped and the other not would be deadly!

share|improve this answer
1  
+1 This is the key quote: "if one has failed, it is likely that the other is in a similar condition and so could easily fail soon" –  Bob Cross Mar 21 '12 at 15:50
1  
I consider it case by case. Standard logic is that both wear at the same rate. However, that doesn't take into account side specific loads and/or damage. Most cars have springs that should last a lifetime in normal use. If you nick one, you've significantly shortened its lifespane. Might consider doing just 1 in that case. Racecars, 1 side only is standard (as the load is asymmetrical, even on road courses (as they're primarily right hand turns and the driver is typically alone and on the left side of the car)). –  Brian Knoblauch Mar 21 '12 at 16:10
    
One cause of spring failure is insufficient dampening.Worn struts or shocks allow the spring to over compress and overextend which shortens the life of the spring.In most cases the struts have to come out to replace the spring .It makes sense to replace them then. –  mikes Mar 22 '12 at 0:43
    
I'd also add that if one has failed, then you've transferred a good deal of its load to the other one, placing it under higher stress. Another good reason to replace both. –  TMN Mar 29 '12 at 15:24
    
It is also possible that the camber will be changed on the 'not replaced' side - as a well used spring will be shorter than the new one - you can't just adjust camber on most road cars. –  user5012 May 7 at 16:00

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.