Star headed wheel bolts

[EmilysDad]

My 'new' ML has the chrome covered star shaped wheel bolts. I see that on the Interweb there's a specific star shaped socket available, however the Merc supplied cheapo brace in the boot is a standard flat faced hexagon. Is this correct or should there be a matching star shaped brace? Or do I just buy one of these myself?

TIA

 

[daveenty]

I didn't even get the cheapo wheel brace with mine Andy.

According to the salesman it's fitted with run-flats so I don't need one. In the real world it has normal tyres but still no brace. A standard 17mm socket will undo them but a proper socket like this would be the preferred route: -

 

[EmilysDad]

I didn't even get the cheapo wheel brace with mine Andy.

According to the salesman it's fitted with run-flats so I don't need one. In the real world it has normal tyres but still no brace. A standard 17mm socket will undo them but a proper socket like this would be the preferred route: -

Thanks Dave. I'll keep the standard brace for the locking wheel bolt key then ...

 

[rifiki]

Yet another type of bolt/stud?

 

[alexanderfoti]

You can use a 17mm socket on them, but over time, it deforms the steel cap on the bolt, that makes the "Star" pattern and they get stuck.

Which is annoying, as when you have the right star socket, they also get stuck once deformed.

Once again, a cost saving measure, stainless steel cap instead of galvanised or phosphated bolts that don't rust.

 

[EmilysDad]

You can use a 17mm socket on them, but over time, it deforms the steel cap on the bolt, that makes the "Star" pattern and they get stuck.

Which is annoying, as when you have the right star socket, they also get stuck once deformed.

Once again, a cost saving measure, stainless steel cap instead of galvanised or phosphated bolts that don't rust.

Thanks for that. I suppose stainless caps are better than plastic

 

[Blobcat]

I'd be taking the locking wheel bolt out, assuming you have the little plastic "briefcase" in the boot with the 4 standard wheel bolts and replacing them with those. Few things more frustrating than not being able to get a wheel off because of a mangled locking wheel bolt

 

[EmilysDad]

I'd be taking the locking wheel bolt out, assuming you have the little plastic "briefcase" in the boot with the 4 standard wheel bolts and replacing them with those. Few things more frustrating than not being able to get a wheel off because of a mangled locking wheel bolt

Not a bad idea. I have the 'briefcase' but have yet to open it

 

[brandwooddixon]

My CL has these.
You don't need a specialist socket, just don't use a bi-hex one.
I use a standard hex socket and you'll find that it works just fine. In fact MB themselves don't use a specialist socket for them.
The shape is to improve retention of the chrome cap.
Just be aware that over time the bolt may rust within the chrome cap causing it to expand.
I replaced those that had been mangled by bi-hex sockets and expanded by rust after I acquired my car. I recall that they're quite pricey from MB at around £10 each.

 

[EmilysDad]

....

I recall that they're quite pricey from MB at around £10 each.

How much? You'd not want to replace them all then

 

[Botus]

Yet another type of bolt/stud?

been about since at least 2006... "strangely" its virtually unknown in Mercedes circles even though its there own proprietary security device that's in addition to locking wheel nuts

a sloppy worn 17mm impact socket by the local animals at the tyre centre goes on and knocks the stainless cap for six, so even your own the security socket no longer fits properly, an unworn conventional socket will not fit on an undamaged one, as "until its been vandalised by the tyre fitters its only 16.8mm between flats"

 

[EmilysDad]

been about since at least 2006... ..

My 07 R Class had the standard OE rusty bolt heads .....

 

[ajlsl600]

You can use a 17mm socket on them, but over time, it deforms the steel cap on the bolt, that makes the "Star" pattern and they get stuck.

Which is annoying

, as when you have the right star socket, they also get stuck once deformed.

Once again, a cost saving measure, stainless steel cap instead of galvanised or phosphated bolts that don't rust.

think that kind of rot started same time the star on bonnet dumped.a yr ago i had a 2 day annoying experience after a tyre firm overdid my security bolts and sheared the fitting from the socket since then i dumped all security bolts for std ,yr right tho the plated jobs are rubbish after a yr. crap on the prices these cars are...sign of the times i keep thinking to send mine off for decent plating ,yet to get around to it ,prob find cant get socket on/off after tho?

 

[brandwooddixon]

I tend to use a Bahco "Six point dynamic drive" socket - the internal faces aren't truly flat, instead being slightly convex, so that no pressure is applied to the points of the bolt but instead to the flats.

 

[Craiglxviii]

You can use a 17mm socket on them, but over time, it deforms the steel cap on the bolt, that makes the "Star" pattern and they get stuck.

Which is annoying, as when you have the right star socket, they also get stuck once deformed.

Once again, a cost saving measure, stainless steel cap instead of galvanised or phosphated bolts that don't rust.

It isn’t a cost saving, stainless is wayyyyyyy more expensive than selective passivation...

 

[alexanderfoti]

It isn’t a cost saving, stainless is wayyyyyyy more expensive than selective passivation...

Surely a small stainless cap is cheaper than a whole phosphates bolt?

If not, then what is the design choice behind it?

 

[Craiglxviii]

Surely a small stainless cap is cheaper than a whole phosphates bolt?

If not, then what is the design choice behind it?

It’ll be a lifetime performance thing. Stainless fixings vs coated carbon steel are around 6x the cost.

 

[alexanderfoti]

It’ll be a lifetime performance thing. Stainless fixings vs coated carbon steel are around 6x the cost.

Yes, but the only stainless bit on the 221 bolts are the pressed cap:



VS the zinc plated ones I use aftermarket:

 

[EmilysDad]

Perhaps Merc should start designing wheels with some kind of centre cap that covers the bolts/nuts too instead of having rusty bolts on show.

 

[daveenty]

Perhaps Merc should start designing wheels with some kind of centre cap that covers the bolts/nuts too instead of having rusty bolts on show.

Something like this perhaps: -



They're an absolute nightmare to get off due to the (plastic) adapter which they supply with them which slips readily. They're also a pain to get back on due to their ability to cross thread at the slightest opportunity. Mine already has one new rim due to Mercedes being unable to put the thing back on correctly, I'd hate to do one at the roadside in anything less than perfect weather.

You can turn it to start the thread a good couple of turns, after that it either goes straight on or locks up solid leaving about a 10mm gap between the centre and the rim.

Horrible things, especially when you're used to whipping wheels off regularly for cleaning purposes, I find myself putting this job off all the time now.