Mercedes Failure

Well, what an interesting and I would have thought unusual failure: a lot of clonking from under Florrie yesterday so had a looksie and the rear offside solid leaf spring has snapped clean through about 12" behind the axle. Been speaking to Northside Mercedes Hull who wanted me to recovery it to them to see if it is warranty. You can make a good guess at my response 15 months old and only 8200 miles and a bust spring.

They didn't want me to call mercedes recovery, not sure why 

Waiting their return call with interest.

Good luck with your van repairs John.
Boaby

Thanks both. Yes, called mercedes recovery and were brilliant. Were coming tonight but I said as not a panic leave till morning if easier. So, have a girt big low loader that takes coaches calling at ours tomorrow morning.

Peter, (or some one else with a Merc chassis), is your rear axle sitting on the rubber bump stops? I would expect it with the broken spring but not the other one as well?

Brilliant, thanks for that Peter. My axle is firmly against the bump stop on both sides even with the good spring side with the unit almost at basic weight so will be interesting to see what is what with a new spring fitted on the other side.
I will 'attempt' a picture ha ha.

Jaytee wrote:Brilliant, thanks for that Peter. My axle is firmly against the bump stop on both sides even with the good spring side with the unit almost at basic weight so will be interesting to see what is what with a new spring fitted on the other side.
I will 'attempt' a picture ha ha.

As far as I'm aware shouldn't springs or shocks always be replaced in pairs? Therefore I would expect both sides to be replaced, in fact I personally think I would insist upon it!

Also, if your axle is touching the bump stops I would have Air Suspension fitted as soon as your new springs are fitted to take the weight off your new springs. Why ever don't Auto-Sleepers fit air suspension as standard on all coachbuilt motorhomes?

Hope you are soon back on the road, great to hear that Mercedes came through good for  you, will have to go and check that mine are ok, and many thanks to Peter for the photos.
Don

Hi Jaytee,
Just looked under my van (Malvern - 3800kgs  and slightly later than Peters) and I can concur with Peter's photos which show both bump stops well clear of the rear axle - if anything mine have slightly more clearance but then I have the rear steadies lowered at the moment so some of the weight is on them. 
I would also agree with Admins comments regarding both springs being replaced - after all with one failing it may have exerted extra (beyond spec)  twisting stress to the remaining one which could contribute to a future failure!
I guess air suspension is one solution but it does add to the overall weight - which may be one reason A/S do not fit it - that is, apart from the additional cost!
Hope it all goes well.
Liam

Very very good point re 'insisting' on both being replaced. 

Pics of bust spring: Cannot get my head around adding pics with the IPad so hope this works 

https://i.servimg.com/u/f38/18/63/03/53/image11.jpg



https://i.servimg.com/u/f38/18/63/03/53/image13.jpg

Interesting photos - I would have said that the spring has been partially fractured for some considerable time! 
If you look at the photo there is a clear sign of rust over half of the surface area which would suggest that it has been exposed to the elements for a long time. 
The remaining portion looks fresh and has little or no rust. Looks like a manufacturing fault to me - a boundary layer failure (very straight) which would have been caused in the forging process. Bad QA by Mercs supplier!!
Liam

That is shocking for a vehicle of it's age - I also second (third or forth) the fitting in pairs. 

These look like assisters Peter. The bit of spongy tape is probably to hide the stress fracture 

This is what you call a recovery truck   Can recover up to 60 tonnes !!!!!! Bit wasted on my lille ole 3.5

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Liam wrote:Interesting photos - I would have said that the spring has been partially fractured for some considerable time! 
If you look at the photo there is a clear sign of rust over half of the surface area which would suggest that it has been exposed to the elements for a long time. 
The remaining portion looks fresh and has little or no rust. Looks like a manufacturing fault to me - a boundary layer failure (very straight) which would have been caused in the forging process. Bad QA by Mercs supplier!!
Liam

Hi there,

Agree entirely.

On the photograph there appears to be an "indent" that goes across the full width of the underneath of the spring about 2mm in on the axle side of the spring.

If it is there (as opposed to there being a photographic anomaly) then it will probably have been made during the forging process and it will have stressed the spring to such an extend that it was almost certain to fail at that particular point.

Bad manufacture followed by bad QA.

I hope you retained the spring to send it to Mercedes to try and get a rebate! 

Best regards,

Thanks Dutto. Yes, I noticed that 'mark' as well. MH is at Mercedes in Hull so waiting to see what they say. Already told them I Want both springs changed regardless but wait and see. Have been wondering if it has been broken for a while as there was very little 'sag' noticeable on that side (as both sides have always been fairly low) and the ride has always been very harsh on rough roads but recently more so. And coming back up from Bournemouth last week I noticed a slight vibration when easing off the power when going over 60mph on the motorway so all adding up.  All good fun and thank goodness for warranty (I cannot possibly believe they can call that user error ).

Hi there,

As Liam pointed out, all the indications are that the "fail" has happened over quite a long time.

If you look at the rust marks on the break you can see "old" rust (the black bit at the top left of the fracture), "new" rust (the orange speckles across the break) and "no rust" (the pale grey bits).

This pattern gives all the indication of a failure that has happened over quite a long period of time and not something that has been caused by a single "event" such as hitting a speed-bump too hard due to inappropriate operation.  (It is critical to prove this otherwise they will blame the driver!!)

In synopsis, from the photographs, it looks as if:

o  There was a groove made in the spring during the manufacturing process.

o  The groove affected the performance of the spring and it started to fail on the top of the spring, opposite the groove, with a small crack that allowed water to enter.  (Old rust.)

o  The failure was a gradual process that allowed the crack to widen and the water to spread across the face of the crack.  (New rust.)

o  The final failure was picked up and photographed almost immediately.  (The grey areas.)

This last bit ties in with your description 


Hope this helps. 

Best regards,

Very good point about speed bumps and definitely not something I would have done. My cab cam has a G meter in it so I will back up the recordings. The grey bits are actually white and there were no grey fresh break marks which is odd. I cannot imagine it has been broken for too long as we only heard the loud clonking last trip out but the ride has always felt as if it had solid tyres at the back 

Good luck getting this sorted Jaytee  

Will be interesting to see if they do indeed replace both sides... keep us updated.

I've started using my corner steadies when the Broadway is parked up on the drive with the thought that it will lift some of the weight away from the springs when its sitting idle, (not sure if this theory will actually work) as we have no air suspension on this motorhome... I don't want to see them sag like our Nuevo had before we fitted Air Rides which lifted the back end and corrected the sagging leaf springs.

I wouldn't use the steadies to support weight - they're only there to steady the van from rocking!
The subframe they're attached to is pretty flimsy in the monocoque  Clubman and if supporting any weight affects the habitation door operation!

It also looks like the weight of the van is being supported purely by the anti roll bar assembly - I'd be asking for that and the propshaft  to be checked,  almost certainly the source of the vibration.

Jaytee wrote:Very good point about speed bumps and definitely not something I would have done. My cab cam has a G meter in it so I will back up the recordings. The grey bits are actually white and there were no grey fresh break marks which is odd. I cannot imagine it has been broken for too long as we only heard the loud clonking last trip out but the ride has always felt as if it had solid tyres at the back 

Curiouser and curiouser!!  

If there were no fresh break marks then where did the "white" come from?

If the "white" area hasn't been caused by the final fracture then it looks as if the spring failed sometime before it was detected; and yet somehow clung together and showed no symptoms.

If this had happened then I would expect to see a fairly uniform pattern of rust across the face of the break or some indication that the two ends had been rubbing together.  Could the two ends rubbing together have caused the "white" bits?

I'm really intrigued with what Mercedes come up with!  Anyone want to bet that it isn't put down to "Driver Error"? 

Best regards,

Dutto wrote:

Jaytee wrote:Very good point about speed bumps and definitely not something I would have done. My cab cam has a G meter in it so I will back up the recordings. The grey bits are actually white and there were no grey fresh break marks which is odd. I cannot imagine it has been broken for too long as we only heard the loud clonking last trip out but the ride has always felt as if it had solid tyres at the back 

Curiouser and curiouser!!  

If there were no fresh break marks then where did the "white" come from?

If the "white" area hasn't been caused by the final fracture then it looks as if the spring failed sometime before it was detected; and yet somehow clung together and showed no symptoms.

If this had happened then I would expect to see a fairly uniform pattern of rust across the face of the break or some indication that the two ends had been rubbing together.  Could the two ends rubbing together have caused the "white" bits?

I'm really intrigued with what Mercedes come up with!  Anyone want to bet that it isn't put down to "Driver Error"? 

Best regards,

I still reckon Peter should look under his spongy tape 

dandywarhol wrote:I wouldn't use the steadies to support weight - they're only there to steady the van from rocking!
The subframe they're attached to is pretty flimsy in the monocoque  Clubman and if supporting any weight affects the habitation door operation!

Thanks for the advice Dandy..  
I've not actually jacked it up as such, but just to the point where its about to take up the weight?
(another turn or two would probably lift it though) Just thought while on the drive it would help stress the springs less, was just a thought...

I'm often in and out of the van most days and have weekly guitar lessons inside it anyway (even watch the TV in it some days) So will probably leave them out as they are...
(As I'm no lightweight)  No issues with Hab door luckily, but that could be because its an End Lounge, the door is at the front not the rear which obviously helps with this

CC

Update:
Just spoken to Northside Truck in Hull and they confirm that it is a broken spring , that was hard.
Anyway, have confirmed they are changing both springs and I asked if they had any idea of cause of break, I.e manufacturing fault etc, nothing yet but will get back to me.
Springs in on Wednesday and will advise.
Can't grumble at service that's for sure