Help; W203 2004 Estate front under-frame rusted through

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DrBob35

New Member
Joined
Oct 5, 2020
Messages
14
Location
Malvern
Car
Mercedes Benz 2004 C-class 270 cdi estate auto
My car has just passed the MOT at 100,000 miles. It is 16 years old of course but I was horrified to receive the information that the Front- sub-frame which holds on the wheels has a rust hole in it. The only accompanying information was that it was not part of the MOT test!!!!!!!
Can anyone, please, shed light on what this part is and how this might add to my sleepless nights? Should I worry about the wheels falling off? If the rest of the under body is OK could it be worth replacing; after all the car is and has been going well and I am loath to scrap it for a replaceable part. Can any one enlighten me please.
Thanks in advance for any replies.
 
I think a few people have had success getting Mercedes to rectify the problem free of charge. Something about all Mercedes having a 30 year chassis warranty.

Worth a bit of research before approaching a Main Dealer.
 
I think on the W203 it's usually the rear subframe.
 
And jasonh, definitely worth booking it in for an inspection at your local MB dealer.

There may be various reasons why they won't cover the repair cost, I.e. it's not a given that they will, but definitely your first port of call should be the dealer.
 
[It has popped into my head that there was a warranty, I might even be able to find the original paperwork. However, I am not the original owner.]
It is a 4 year reliability package and a 30 year free breakdown assistance "mobilo-life*[ *terms and conditions apply.] I used that when a battery cell failed. I had to pay over the odds for a battery though.
It was an MB main dealer who did the service and MOT. Word of mouth said Front-sub-frame. I have got a quote now and it just says sub-frame. They did seem very reluctant to give a quote it took a second time of asking and waited a week; I suspect they were embarrassed.
I seem to remember that, in the old (and better days?) a Main Dealer could process a claim.
What's the point of contact at Mercedes UK for warranty discussions?
 
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[It has popped into my head that there was a warranty, I might even be able to find the original paperwork. However, I am not the original owner.]
It is a 4 year reliability package and a 30 year free breakdown assistance "mobilo-life*[ *terms and conditions apply.] I used that when a battery cell failed. I had to pay over the odds for a battery though.
It was an MB main dealer who did the service and MOT. Word of mouth said Front-sub-frame. I have got a quote now and it just says sub-frame. They did seem very reluctant to give a quote it took a second time of asking and waited a week; I suspect they were embarrassed.
I seem to remember that, in the old (and better days?) a Main Dealer could process a claim.
What's the point of contact at Mercedes UK for warranty discussions?

There's no harm in contacting MB UK, though chances are that they'll simply refer you back to the dealer.
 
I finally have the full story of my FRONT sub-frame rust hole; it is a very small hole, does not make the car dangerous to drive.
On my Mercedes the front sub-frame is covered so it cannot be seen without partial dismantling. If this had not been the case the car would have failed the MOT. It did not fail because the examiner could not see it and is not allowed to dismantle anything; so it passed!!! The rear sub-frame is A-OK.
A new front sub-frame is in excess of £900 inc VAT. Second hand ones are £50-£300.
I am told that with some old cars a welding process with plates to maintain the integrity of the structure of the car can be used. It should then be safe and an MOT should not be an issue. This method may, or may not be cheaper in the long run. Has anyone experience of this method?
 
I finally have the full story of my FRONT sub-frame rust hole; it is a very small hole, does not make the car dangerous to drive.
On my Mercedes the front sub-frame is covered so it cannot be seen without partial dismantling. If this had not been the case the car would have failed the MOT. It did not fail because the examiner could not see it and is not allowed to dismantle anything; so it passed!!! The rear sub-frame is A-OK.
A new front sub-frame is in excess of £900 inc VAT. Second hand ones are £50-£300.
I am told that with some old cars a welding process with plates to maintain the integrity of the structure of the car can be used. It should then be safe and an MOT should not be an issue. This method may, or may not be cheaper in the long run. Has anyone experience of this method?
Yes, had a W210 with the same problem. Had the existing piece welded up over the hole with same thickness of material, painted over with rust proofer and AFAIK the car is still on the road, many many years later. As you say the offending item is above the engine under tray so cannot be seen. It was seam welded not spot welded.
 
For those interested, I have now had this problem appraised by a Motor Structural Engineering Garage. It transpires that there is nothing wrong with the front sub-frame; incidentally this is reported as made of alloy. The offending part is a formed ferrous metal plate, a trivial part of the support for under-body components; for example the engine protection plate. It has a small hole rusted through.

The only problem now is to get the 16 year old steel bolts out of the alloy sub-frame. Otherwise cost is very reasonable and should take 2 hours for job done.
Lesson learned: Don't believe everything you are told from a casual observation of a 16 year old car which is, no doubt, a pain for MB main dealers. They, like Jackdaws, like shiny new things.
 
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The only problem now is to get the 16 year old steel bolts out of the alloy sub-frame. Otherwise cost is very reasonable and should take 2 hours for job done.
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If it's anything like my '04 203, be very careful. I needed to remove the anti roll bar and to cut a long story short the four bush retaining bolts (steel bolts into the alloy subframe) all sheared, despite liberal applications of Plus Gas the day before. It didn't need that much force to shear them either. Nothing in my tool box could shift the remaining 'studs', I ended up taking it to a local garage who spent over an hour under it with oxyacetylene.
 
Thanks Stratman. Noted. It's going to the garage anyway I am happy they know what they are doing. By the way Jackdaw should have been Magpie!
 
So did you try to get this assessed for warranty repair by the dealer and it was rejected? Or did you never go down the warranty route?
 
I did not go the warranty route Markjay because it isn't a sub-frame problem. It is a component support bent-up steel plate problem which can be replaced at very reasonable cost compared to a new sub-frame replacement. Saves wear-and-tear on the nerves.
 
To round off this thread I can say the deed has been completed. The car went into an (independent) garage and in 2.75 hours the new "Support Bracket" (£50) had been fixed, recalcitrant bolts and all. Total cost 18% of that quoted by Mercedes for the wrong part!
Thanks to all those who contributed to this thread with their knowledge and encouragement.
 

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