Country lanes and springs.

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Dieselman

Banned
Joined
Jul 13, 2003
Messages
34,206
Car
Peugeot 403 Convertible
A couple of mornings ago I was giving it full on beans down some twisty country lanes and a short while later heard and felt a sort of Bang/Twang noise.

Thought I'd better check, so jacked the car up and......

Spring from front side..

Picture001.jpg




Spring from rear side....


Picture006.jpg



Close up of break...


Picture009.jpg




Just waiting on a price now.....:crazy:
 
You might find that the springs are pretty cheap from the stealership. Shocks cost a bomb but the springs are well priced.
 
Just bargained a price to £80 inc the pair.
 
You might find that the springs are pretty cheap from the stealership. Shocks cost a bomb but the springs are well priced.

Got OEM BOGE dampers direct from BOGE at a price the trade wouldn't get, was very happy...:)
 
Make sure you get the sacraficial anodes for the bottom of the spring. (little aluminuim sleeves)
 
I was going to keep the originals, bad idea?
 
Normally they are in poor condition when removed (worn out) and sometimes get damaged in the removal.

I would say it is best to renew them.
 
Just done the job of replacing the springs and a full B service. Interestingly the car called ZERO miles to service on start up this morning...Spooky hey..:rock:


Had a hand from a Mate (Cheers;) ) which was a good job as it turned out to be 2 man job due to a faulty spring compressor.

Should have been really simple, lift car remove wheels, fit compressor, remove and replace spring.

Well it went ok to start with..:)

Car in the air compressor fitted.

FrontspringsCompressorready.jpg



Then disaster...the drive on the compressor gave out under the load so no more tension could be applied.:(

Spent a while looking for another compressor but to no avail so resorted to plan B, which meant propping the wishbone and undoing all the bolts holding it on, damper, anti-roll bar, inner bushes.


Wishbone propped

frontspringwithprop.jpg


Picture of old anode that sits under the spring, always change them with the springs. One was so corroded it was welded to the wishbone and had to be chiseled out.

Frontspringsanode.jpg



With the old spring out and a new one in it was seriously hard work getting the inner bushes to line up due to the wishbone being propped and under tension. By tension I mean the car was lifting off the ramp and still the spring wasn't compressed enough.

FrontspringsPuttingwishboneback.jpg



The only way to do it was to remove the prop completely so the spring wasn't under tension all. It can't quite come out but has no tension left in it so is safe.


Frontspringnosupport.jpg




After putting it all back together moved onto side 2, which was a lot easier due to learning the way to do it.

Prop the outer end of the wishbone and lower the ramp to compress the spring (the same effect as jacking the wishbone up at the outer end), then fit the spring compressor and do it up only as tight as it would go.
With the damper and anti-roll bar disconnected removing the spring was no problem.

Frontspringsside2.jpg




So what did we learn.


Well it is definitely possible to change the springs without a working proper MB spring compressor.


I would jack up the car by the outer wishbone joint and fit standard compressors and tighten them as much as I could.
There is space to fit them but you can't tighten them in situ hence the jacking first.
Then remove the damper bolt and anti-roll bar bolt and there should be enough space to withdraw the spring.

This contradicts anything you may be told about it not being safe to remove the spring without the proper tool, but I assure you the spring is under no tension once the damper and anti-roll bar are disconnected. Regular compressors will then have enough space to operate.
 
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How does the car sit now? A little high or just as before?
 
Just the same, but feels slightly tighter over bumps. I might consider doing the rears as well if I like the feel and it doesn't settle away.

I could tell one spring was slightly loose, but it was only half of the bottom coil broken off.

The trick to the ride height is to use OEM springs as I have.
 
Does the fracture on the spring look like a fatigue break or a shock failure? I only ask as it might indicate that your dampers are past their sell by date.
 
The dampers are only 13K old all round.

The break is a shock break, you can see it on the first post of this thread.
 
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I could see from the first post that the outside edge was a shock failure. I only wondered if there were any different signs on the parts of the failed area not visible while it is still in the car.
 
No, just a clean break all the way through, fresh corrosion on the broken ends but no evidence of previous stress or corrosion.
 
Good post. When I mentioned a while back it was possible to do the job without the Klann compressor most said it was not safe to do so but it clearly is, albeit somewhat slower !
My old W124 E320 had both front springs broken like that and it still got through the MOT twice !

adam
 
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Scc

Breakage is probably due to SCC stress corrosion cracking. http://www.npl.co.uk/lmm/docs/stress.pdf
Combination of unrelieved stress induced during manufacture or operation and presence of corrosive ions e.g. chloride can lead to unexpected failure. Can be combated with sacrificial anodes or by stress relieving components by heat treating as part of the manufacturing process. There was a rumour that H and R springs did this stress relieving but dont know. With the amount of salt spread on our roads now its almost a certainty your front ( most vulnerable to salt and coating damage) will fail at some point 100k+ miles ?? in your Mercedes lifetime. If on inspection your front springs have some corrosion on them or the coating appears broken particularly where they rest on the wishbone then your risk of sudden spring failure is markedly increased IMHO. Fortunately most fractures occur where the spring sits on the wishbone and failure does not present an immediate safety problem. Still worth checking on higher mileage cars tho.
 
Did you tighten the wishbone bolts when the car is off the ground ? I was reliably informed they must be tigntened when the vehicle is on the ground.The reason for this is because if you dont it will twist the wishbone bushes and wear then out prematurely.
 
Did you tighten the wishbone bolts when the car is off the ground ? I was reliably informed they must be tigntened when the vehicle is on the ground.The reason for this is because if you dont it will twist the wishbone bushes and wear then out prematurely.

You are correct.
We applied pressure with a stand to raise the wishbone to the correct operating angle before tightening wishbone and damper bolts.
 
How to waste and evening.!

Being pleased with the feel of fitting the new front springs I decided to do the rears as well as due to the fronts feeling better due to being a bit stiffer, which has improved the handling markedly.

Not having a MB spring compressor was going to make this 'interesting' but not one to pass up a challange...

Being lazy I wanted to do both sides together.
Reverse the car onto ramps and jack up under the differential.. Place axle stands under the inboard bushes for the suspension arms.

Rearspringsjack.jpg


Lower the car onto the axle stands and undo the nuts and withdraw the bolts.

Rearspringspivotbolt.jpg


Jack the car up so the suspension arms gradually drop away from the sub frame.

rearspringslowerarm.jpg


Pull down the arm and withdraw the spring.

Rearspringremovespring.jpg



At this point you can take a little time to wire brush and rustproof the inevitable corrosion on the upper spring cup and inside the wishbone...:D

Refitting is the reverse of removal.

Now just like every good story there is a twist....here it is...the dealer has supplied the wrong springs so the new ones are too long to fit into the wishbone clearance....Doh..!

So having put it all back together with the original springs I will do this job again when the correct springs arrive....
 

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