W212 Rear Coil Spring Snapped / Broke Replacement

[pmcgsmurf]

Checking over the W212 (2010, 20k miles) for its MOT.

Surprised to see this.



New Springs ordered.

Anyone have the WIS handy for the W212? Save me searching torque settings.

I'll stick some updates on when I fix it as not seen much here for the W212.

 

[pmcgsmurf]

Spring out.

Official WIS says just to use an Internal Telescopic Spring Compressor without taking any of the suspension to bits.

Didn't have one to hand so:

1. Remove plastic cover on bottom of suspension arm.
2. Loosen bolt/nut at rear of suspension arm to allow it to swing.
3. Support arm with jack.
4 Remove bottom shock absorber bolt.
5. Remove bottom drop link bolt.
6. Lower arm out of the way gently and remove spring.

 

[Abb]

You could have always cut the other three down to match!

 

[pmcgsmurf]

You could have always cut the other three down to match!

You are not wrong, watch this space, found more doom and gloom today.

 

[pmcgsmurf]

Checked the other W212 today as well, same spring snapped in exactly the same place.

 

[clk320x]

That’s exactly how my one had snapped... at over 200k though

 

[pmcgsmurf]

When you get the spring out there is a shim on the bottom that goes into the suspension arm.
The part that Mercedes say to always also replace with the spring that most little garages don't bother with.

Both springs snapped in the same place, just above where the shim steps down.
I reckon either water, dirt and other poo stuff sits in here possibly along with the spring hitting this when compressed causing the coating to come off allowing the spring to corode in this area and ultimately fail.






I've only got an external MacPherson Strut style compressor.

Might go and buy an internal one now given that I'm gonna be doing 4 of these.

 

[pmcgsmurf]

That’s exactly how my one had snapped... at over 200k though

At that mileage I don't think many would argue.
The one on 20k I'm a bit peeved about, at least I've caught it though so not all bad news.

 

[Deleted member 113659]

Good work Pat.

 

[Abb]

Sorry to hear that Pat. MB springs really are shite! Almost as bad quality as their wheels that keep cracking! My 218 springs were found to be the same as yours (less than 50k miles), both rears cracked in the same place (albeit at the top). I replaced with H&R items!

 

[pmcgsmurf]

Edit to post 2, realised the way I described the arm would still be attached to the wheel carrier.
-------------------
1. Remove plastic cover on bottom of suspension arm.
2. Loosen bolt/nut at rear of suspension arm to allow it to swing.
3. Support arm with jack.
4 Remove bottom shock absorber bolt.
5. Remove bottom drop link bolt.
6. Remove bolt suspension arm to cheel carrier.
7. Lower arm out of the way gently and remove spring.
-------------------

 

[pmcgsmurf]

Sorry to hear that Pat. MB springs really are shite! Almost as bad quality as their wheels that keep cracking! My 218 springs were found to be the same as yours (less than 50k miles), both rears cracked in the same place (albeit at the top). I replaced with H&R items!

They certainly are crap, already done the front springs on one of these W212.
I've got Imp springs that are 50+ years old and have not snapped.

I had a quick look at alternates but nothing stood out so just went OEM.

 

[pmcgsmurf]

Ordered an Internal Telescopic Spring Compressor from Amazon to try, £60 delivered.
Got to be worth it for £15 per spring and we can also utilise this on our Imps.

 

[Trickythemerc]

I have had to replace springs for the last two MOT's. Both fronts failed and one rear, stay clear of aftermarket stuff they are not worth the bother and do replace the sacrificial shims in the lower wishbones.

 

[pmcgsmurf]

I have had to replace springs for the last two MOT's. Both fronts failed and one rear, stay clear of aftermarket stuff they are not worth the bother and do replace the sacrificial shims in the lower wishbones.

Yes, although the Merc. ones have failed they have lasted 10 years and the ride height etc. is correct.

I may look at adding some grease etc. to the bottom to protext that area of the spring.

 

[Will]

Pretty much all Mercedes springs corrode and snap like this and have done for years. I’ve had this myself on W201 (190Es), 203 C-class and 210 and 124 E-class as well as a Lexus some years back.

I don’t think mileage has all that much to do with it, they get wet and water runs down the spring settling at the bottom cup, which gets paint worn away due to friction etc, then they corrode away and snap. It’s always the bottom coil!

Does happen to quite a few other modern cars also to be fair.

Last one I changed on a 210 estate was around £60ish new from my local main dealer and they match them up to the vehicle options etc (colour coded) - not too bad. I understand your frustration at just 20k miles but it looks like it’s seen a bit of road salt/wet weather at some point?

 

[johnsco]

It's not just MB whose springs are poor.
I recently replaced both rears on Mrs J's Peugeot.
Both in the same place ... Bottom rung.
It's because they are coiled in manufacturing (as always) but are no longer properly stress-relieved and are therefore liable to suffer stress-corrosion.
The protective coating fails (as in photos above See post #7).
Corrosion starts on the surface.
Stress corrosion quickly makes its way thru the spring ... and BINGO ... The spring snaps.

 

[pmcgsmurf]

Pretty much all Mercedes springs corrode and snap like this and have done for years. I’ve had this myself on W201 (190Es), 203 C-class and 210 and 124 E-class as well as a Lexus some years back.

I don’t think mileage has all that much to do with it, they get wet and water runs down the spring settling at the bottom cup, which gets paint worn away due to friction etc, then they corrode away and snap. It’s always the bottom coil!

Does happen to quite a few other modern cars also to be fair.

Yes doesn't seem to be a Mercedes only thing, quite common now.
We've done quite a few as well over the years, even done the 211s before they snapped as I became paranoid about them.

Last one I changed on a 210 estate was around £60ish new from my local main dealer and they match them up to the vehicle options etc (colour coded) - not too bad. I understand your frustration at just 20k miles but it looks like it’s seen a bit of road salt/wet weather at some point?

Certainly seems to be where the dirt, water etc. gathers in that area coupled with the friction.

I'm not too worried, it's a 10 year old car after all and has served me well even if not that many miles.
Gives me a good excuse at the end of the day to take things to bits which is what really makes me happy.

 

[pmcgsmurf]

It's not just MB whose springs are poor.
I recently replaced both rears on Mrs J's Peugeot.
Both in the same place ... Bottom rung.
It's because they are coiled in manufacturing (as always) but are no longer properly stress-relieved and are therefore liable to suffer stress-corrosion.
The protective coating fails (as in photos above See post #7).
Corrosion starts on the surface.
Stress corrosion quickly makes its way thru the spring ... and BINGO ... The spring snaps.

It's quite easy to see how the stress corrosion happens with the protecitve coating having come off.

Two of the new springs have arrived, the other two wont be here till Tuesday so maybe leave it till then to collect. Give me some time to do other things as one still needs a B service.

 

[pmcgsmurf]

Spring Compressor arrived today, quick test, does the job and looks ok.