Name this bolt?

[Carvice]

hello to all
Today I wanted to take out my siren box as it started to chirp on doing so I noticed a nut and bolt missing.
I’m not sure how long it’s been missing but from the dirt around the hole I’d say a little while.
I’ve looked all over the net trying to find the name or part no but can’t find any information on the part I need and it’s seems like a major bolt that needs to be replaced ASAP.

It’s a c class w203 2003
The bolt is connecting the top of the hub to the shock.

If you could tell me the part no or how I could locate one I’d be truly thankful.

 

[Richteo]

Pretty sure its

Bolt A0009902403
Washer x2 A1249903740
Nut A0019908454

Really should n't drive with these missing! The bolt is M14x1.5 pitch, 45mm long, i.e. fine thread. Don't know what grade this bolt is but I have seen 10.9 marked on the head of other merc bolts if you need something urgently from another supplier.

 

[Datadogie]

I would say very lucky you spotted that.

 

[Carvice]

Well I think I might know when it fell off, about 2 months ago I felt something hit and go round the arch (same side as missing bolt) I did a you turn just to see what it was and saw what I thought at the time was a wheel nut and having checked mine where all there I thought it wasn’t off my car. Now thinking back it’s quite possibly the nut that’s missing. Yes I feel lucky as I’ve done quite a few motorway miles since.

Can I go to Mercedes and show them the picture, will they be able to tell from a picture the parts I need?

 

[Datadogie]

They probably wont have one in stock. People will hate me for this. But I would go to my nearest car srapyard.

 

[bob6600]

For an important bolt like that I would just get it from MB

 

[Codger49]

As long as you also tell them the vehicle's VIN.

Have attached extracts from MB's EPC (Electronic Parts Catalog) for a 2003 C180 (203.035), and you can see from the footnotes that there was a part change in mid 2003. PS Don't see any washers on that diagram.

If you post up your VIN, many forum members have access to MB's EPC (Electronic Parts Catalog) and can tell you the part numbers for your specific car. (Caveat, as originally built.)

PS These nuts and bolts are usually described as not to be re-used as they may well be torqued beyond their elastic limit.

 

[Carvice]

Thanks very much, yeah looks like there should definitely be washers.
Good point about not reusing them, can Mercedes supply the correct torque setting when purchasing?

 

[Codger49]

If the dealer's parts man can be troubled to look up WIS (not all will).

As I mentioned above, post up your VIN and forum members can look up WIS (MB's workshop instructions) for your car and find out the torque settings.

 

[grober]

Check the bolt/selflocking nut/washer size from what's on the other front suspension strut.
torque setting here
Front axle shock absorber - WIS

Remove/install the suspension strut - WIS

 

[Carvice]

Yes this looks like the nut and bolt I need, sorry I’m not a mechanic, and can’t translate the correct nm that bolt requires. Also
Do you have a part number for that nut and bolt.

 

[Codger49]

I note the WIS extract posted states the Allen headed bolt, washers and nut are to be replaced by a round bolt and hex nut without washers. This would match the A 000 990 24 03 (bolt) and A 001 990 84 54 (nut).

The torque required for this nut is that given by BA32.25-P-1010-01B, i.e. Stage 1 100nM and then a further 90 degree (quarter turn) rotation.

Given the critical safety aspect of this connection and that 100nM +90 degrees is quite tight, especially if counterholding the bolt head is required, perhaps you should consider using an independent Mercedes specialist to replace the missing bolt for you. I don't know Norwich, but Googling reveals several indys, someone like AutoTechnic would probably do this at a low cost.

 

[Carvice]

Thanks for the info, yeah might get specialist to do it. Thanks for doing the research too. I’ll get the other side done at the same time.

 

[grober]

Sorry I missed your enquiry yesterday. Codger49 has given you good advice. Its essential with a safety critical component to have the right tools/experience for the job. Usually when Mercedes change a fastener spec/torque its down to a history of failures in the field- this can be due to an incorrect engineering spec [ unusual] but usually down to faulty installation either on the assembly line or retro fitting [ people re-using stretch bolts] An explanation of TORQUE AND ANGLE here.

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[Datadogie]

I hate to object about re-using bolts. I may be nieve, but what you are trying to say is that when you take your to Quickfit Halfords Budjet ect. to have new springs or struts fitted that they use new nuts and bolts. I don't think so.

 

[grober]

No what I said was its not good practice to re-use high torque safety critical bolts and self locking nuts and in particular stretch bolts which are "one use" only. That doesn't mean that this re-use doesn't happen more than people might care to think --- usually for expediency/turn around pressure in certain garages. Mercedes bona fide fasteners are possibly not stocked at dealership level but are usually next day delivery from central spares holding. Such reuse of old bolts may have resulted in the OP's present situation.

 

[Carvice]

Thanks for the info guys, going to Mercedes tomorrow to see if I can order the parts, and possibly the other side too. I recently had the wheels balanced and thought a was getting a wobble more and more on the steering, seems like that will be the reason.

Does anyone know if mb doesn’t stock the part can they mail it to me or is it collection only.

Thanks

 

[milleplod]

Does Mercedes not tell users, via WIS or whatever, which bolts should be renewed? I only ask because I've fitted new suspension to my BMW bike a while back - the factory workshop CD RePROM I have points out very clearly which bolts to renew. If it doesn't say to use a new bolt, or nut, I don't buy one.

Pete

 

[grober]

Some dealerships Edinburgh, Newcastle etc have an internet presence and you can buy direct and get stuff delivered. That doesn't mean they stock it--- just like your local dealer they will order it in and then send it to you.It would be no quicker than your local MB dealer parts counter. If not in stock parts to special order are usually non returnable and may require payment up front- policy varies.

Mercedes and Smart Newcastle | eBay Shops

mercedes-benz-perth on eBay

 

[Bellow]

Bolty McBoltface. And it has sailed.
Can hardly believe the suspension didn't collapse catastrophically with that bolt missing.

Re reusable. Generally, if the bolt is clamping and torqued to stretch - replace. If in shear, endlessly reusable as all tightening is for is retention.
In this case it is mainly in shear with a slight clamping to ramp up the friction between the upright and the strut so I'd have no qualms about reusing - if I actually had the bolt that is.