Must you replace in pairs

Author
Discussion

dieseluser07

Original Poster:

2,452 posts

116 months

Wednesday 15th November 2017
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Snapped coil spring, partners car she isent that bothered its just a run about.

Does it have to be replaced in pairs? In the past garages have never told me it should have both done but ive read on the web its reccomended.

Im more concerned about safety, will it be safe to drive with just the broken coil spring replaced?

curlie467

7,650 posts

201 months

Wednesday 15th November 2017
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Safe but it's recommended to do in pairs as you know.
I try to do any suspension component as a pair.

DuraAce

4,240 posts

160 months

Wednesday 15th November 2017
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Not mandatory.

I would do a pair on anything decent/quick etc.

My mum's shopping car that never goes above 40? Then no.

parabolica

6,712 posts

184 months

Wednesday 15th November 2017
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Changing in pairs is best practice but not necessary. Why did it snap? If it was fatigue then the other spring probably isn't far off so it would be ideal to replace both at once. If she whacked kerb or something and that was the cause, then depending on how old the springs are you can probably change just one.

dieseluser07

Original Poster:

2,452 posts

116 months

Wednesday 15th November 2017
quotequote all
parabolica said:
Changing in pairs is best practice but not necessary. Why did it snap? If it was fatigue then the other spring probably isn't far off so it would be ideal to replace both at once. If she whacked kerb or something and that was the cause, then depending on how old the springs are you can probably change just one.
Not sure how old springs are but car is 8 years old, she goes over bumps quick so potentially caused by that i dont know, its snapped at the top of the spring if that makes any difference.

She drives on the motorway most of the time or round town.

MNBrennan

118 posts

157 months

Wednesday 15th November 2017
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Yeah best practice but not strictly necessary. Might end up in the car looking a bit skew whiff!

edc

9,234 posts

251 months

Wednesday 15th November 2017
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Replace the pair and keep the good old one as a spare would be my approach.

jkh112

21,966 posts

158 months

Wednesday 15th November 2017
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In the past I have replaced a single spring and not suffered any noticeable issues. More recently I did change a pair on one of my cars, but only because one snapped through corrosion and the other one looked a bit rough.

227bhp

10,203 posts

128 months

Wednesday 15th November 2017
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Safety; replace as a pair. There is a possibility of mismatched springs and the car won't react as it should in an emergency.

thebigmacmoomin

2,798 posts

169 months

Thursday 16th November 2017
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Why would you want a brand new spring on one side & a potentially old and knackered old one on the other side. As one would be old & worn, it would not feel the same nor would it react the same when needed over bumps etc.

andyf1140

54 posts

110 months

Thursday 16th November 2017
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thebigmacmoomin said:
Why would you want a brand new spring on one side & a potentially old and knackered old one on the other side. As one would be old & worn, it would not feel the same nor would it react the same when needed over bumps etc.
I replaced a single spring on my wife's KA when it snapped and there was no difference in handling side to side so I would just replace the broken spring. BTW did the same on my roadster when a rear spring broke and it still handles the same as well.

E-bmw

9,195 posts

152 months

Thursday 16th November 2017
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Rule of thumb with suspension.

If one was worn/weak enough to break/fail so is the other.

dieseluser07

Original Poster:

2,452 posts

116 months

Thursday 16th November 2017
quotequote all
thebigmacmoomin said:
Why would you want a brand new spring on one side & a potentially old and knackered old one on the other side. As one would be old & worn, it would not feel the same nor would it react the same when needed over bumps etc.
Because unlike me my partner doesent really test the HANDLING of the car all that much. She just wants to spend the least on the car possible.

I was mainly concerned from a safety point of view and 3 garages ive asked say its fine to do one side and i imagine there are thousands of non pistonheaders who have only replaced one and suffered no ill effects.

GreenV8S

30,186 posts

284 months

Thursday 16th November 2017
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dieseluser07 said:
I was mainly concerned from a safety point of view
I'd have two concerns.

If one spring has failed for no obvious reason then the other spring, presumably from the same batch, is also suspect.

If the new spring is not exactly the same length and stiffness as the old one on the other side then you can end up with a car that has weight jacking. You might not notice it in normal driving but it could give the car some alarming handling in an emergency stop situation.

Given how cheap springs are and how much work is involved in ruling out those two concerns, I think the normal advice to replace springs, dampers, brakes, tyres in pairs is appropriate here.

CarsOrBikes

1,135 posts

184 months

Tuesday 21st November 2017
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changing just one is acceptable in my opinion if the other is not ancient, the rates and heights will likely be different, far worse if you put an aftermarket spring with an OE spring, that's poor practice but loads of people do it. They're not exactly expensive parts in the great scheme of things are they, but the labour is something people wish to avoid especially if problematic bolts and working outside I guess.

SebringMan

1,773 posts

186 months

Wednesday 29th November 2017
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227bhp said:
Safety; replace as a pair. There is a possibility of mismatched springs and the car won't react as it should in an emergency.
You assume the springs are perfectly matched.

IME stuff in the aftermarket rarely is unless you go with Sachs or the OEM, short of going genuine.