Treating rusty coil springs

[PositronicRay]

While I fit new lower control arms should I tackle rusty springs?

I'm more concerned with preservation than aesthetics. Springs are quite rusty should I wire brush and use a rust convertor (I've 1/2 a bottle of hydrate 80 in the garage) and paint with something or other or just not bother?

[stevieturbo]

PositronicRay said:

While I fit new lower control arms should I tackle rusty springs?

I'm more concerned with preservation than aesthetics. Springs are quite rusty should I wire brush and use a rust convertor (I've 1/2 a bottle of hydrate 80 in the garage) and paint with something or other or just not bother?

have them blasted and powdercoated ?

Although any springs I've seen fail usually just break, dont think corrosion has ever been a cause of failure on any I've seen

[PositronicRay]

Thx

Blasting and powder coating sounds expensive, new ones are only £50 each. It was mentioned as an MOT advisory.

[andyiley]

Have a word with your local place that does it, as it isn't that expensive.

A few years ago it cost me £30 to do a sub-frame on a motorbike that was probably bigger than 2 springs.

[stevieturbo]

As above, it shouldnt be dear.

Although if you're really that concerned and are in there working already, just replace them.

A bit of preventative maintenance isnt a bad thing.

[b2hbm]

I had that as an advisory a few years ago because the paint coat had started to fail on the top coil. It turned out to be only surface rust & I just cleaned up and covered in waxoyl, it was never mentioned again.

If yours are rusty with noticeable pitting then I wouldn't blast & coat because you've already lost some of the working thickness even if it is minimal. Given the cost of new springs against what's effectively painted xx year old ones then I'd just throw them away and fit new.

[PositronicRay]

b2hbm said:

I had that as an advisory a few years ago because the paint coat had started to fail on the top coil. It turned out to be only surface rust & I just cleaned up and covered in waxoyl, it was never mentioned again.

This sounds sensible.

[HustleRussell]

Springs do sag and go out of spec over the years, even if they don't snap. For the price difference, just replace them. What are you/your mechanic going to do with a car with no springs while they go off to the powder coaters for a day or two?

[PositronicRay]

I've other cars I can use so being off the road isn't an issue.

New springs (Sachs) are only £50 each so I could replace them but the car sits level and drives nicely. I think I'll go with wire brushing and waxoil.

I'm replacing the control arms because I noticed a knackered ball joint the other day when fitting new dampers. If I have to do the springs @ a later date it's no biggie.

[Mr2Mike]

stevieturbo said:

have them blasted and powdercoated ?

Although any springs I've seen fail usually just break, dont think corrosion has ever been a cause of failure on any I've seen

They don't fail by rotting away. Surface pitting from corrosion encourages cracks to start forming, and eventual failure.

[stevieturbo]

Mr2Mike said:

They don't fail by rotting away. Surface pitting from corrosion encourages cracks to start forming, and eventual failure.

Point was, nearly every broken spring I've seen has had no corrosion. They just break.

[b2hbm]

stevieturbo said:

Mr2Mike said:

They don't fail by rotting away. Surface pitting from corrosion encourages cracks to start forming, and eventual failure.

Point was, nearly every broken spring I've seen has had no corrosion. They just break.

I agree, I've seen otherwise sparkly clean springs which have broken, the wife's Audi for one.

But Mike's quote is correct and any pits will form stress raisers & encourage fatigue failure. Hence the only practical thing the MoT inspector can do is highlight when corrosion starts because if left unchecked it will go down that route. Sometimes this will be heavy corrosion, other times it'll be like mine and just a light dust, so easily sorted.