why I hate previous owners - rounded 5mm bolt

BMW intake cam position sensor, the 5mm bolt is rounded off. I can barely get vice grips on it and couldn't get the bolt to turn. Any suggestions or words of encouragement?

Torx bit hammered in?

Always hammer in a new socket?

Oup, too late for that. Hammer in a 5.5mm or 7/32 socket? (Same difference)

JtspellS wrote:

THIS!!!!!!!!!! Life-changer.

fritzsch wrote: Torx bit hammered in?

^ This. Or try a standard size allen and see if its slightly larger, like a 7/32".

Go back in time and don't buy German cars that use soft allan head bolts.

Hammer in a torx or an EZout. Every German car mechanic needs a good selection of EZouts for this very reason.

I'm buying that set of tools, just because.

Was able to get a dremel in there and grind some flats. Removed the power steering reservoir which gave me a straight shot with a big screwdriver. In retrospect removing the PS reservoir was key - I had though about (and tried) hammering something in but there was not enough room to get a mean swing.

Appreciate the help guys.

fritzsch wrote: Torx bit hammered in?

Into the fubared fastener, or the previous owner???

Oh, and nothing was going in. I mean it was round. I have no idea how that happened upon the last time someone's tool touched it. I would have had to start trimming plastic away to get something completely over the head. I had just enough space in one orientation to lock vice grips onto it as my first try.

grafmiata wrote:

fritzsch wrote: Torx bit hammered in?

Into the fubared fastener, or the previous owner???

You sure don't want my opinion of that right now.....

I really don't understand the German fascination with allen head/internal wrenching bolts. They strip/round much more easily than traditional bolts, partly because it's difficult to visually tell if the socket is seated properly or if it's only a couple mm in. Plus they require much more clearance behind them to fit a socket in, no box-end-wrench capability.

So... why do they do it?

codrus wrote: I really don't understand the German fascination with allen head/internal wrenching bolts.

Internal drive fasteners take up a little less room than a conventional bolt, that would be my guess as to whey they're used.

codrus wrote: I So... why do they do it?

The engineers have determined the optimal method. There will be no discussion.

codrus wrote: I really don't understand the German fascination with allen head/internal wrenching bolts. They strip/round much more easily than traditional bolts, partly because it's difficult to visually tell if the socket is seated properly or if it's only a couple mm in. Plus they require much more clearance behind them to fit a socket in, no box-end-wrench capability. So... why do they do it?

torx and allen head bolts are easier to load onto and install with tools on a moving assembly line- if they can save a third of a second on the installation of each bolt at the factory, that adds up to a lot of extra time to install more fasteners.

plus, they just look high tech, and those Germans loves them some stuff that looks high tech.

Blame zee Germans!

In reply to Streetwiseguy:

Our on-going office joke about German cars is "It isn't designed incorrectly - you're using it wrong!"

novaderrik wrote: torx and allen head bolts are easier to load onto and install with tools on a moving assembly line- if they can save a third of a second on the installation of each bolt at the factory, that adds up to a lot of extra time to install more fasteners.

This. Time is money and German workers are expensive... In addition to a good collection of removal tools, it's also a good idea to keep a selection of Allen head bolts in stock so you aren't forced to reuse a partially buggered bolt, which is likely what happened in the OP's case. It was buggered during removal and the then more so again during re-installation.

novaderrik wrote: plus, they just look high tech, and those Germans loves them some stuff that looks high tech.

And yet they also seem to be stuck in the 80's with regards to fashions and mullet hair styles...

Those damn 'triple square' bolts they love make no sense to me either.

At least the Japanese finally got away from Phillips and JIC screws in motorcycles, I nearly wept with joy when I saw that my XR400 was assembled with 8mm flange head bolts just about everywhere.

Ian F is right on the money, the Germans also seem to be stuck about 15-20 years behind the planet on clothing and hairstyles, the ones I met at the indie Mercedes shop were pretty much 1980's. The Scorpions band publicity pics are also a testament to that.

Curmudgeon wrote: Those damn 'triple square' bolts they love make no sense to me either.

Gah! Thanks for reminding me... I'll be dropping the trans on the TDI in a month or two and the bastards at VW used those to attach the inner CV's to the output flanges... I've already broken two triple square tools the last time I removed some.

maybe it is the german in me.. but I like allenheaded screws and bolts. I have never stripped one out...

As an owner of several saabs.. I have become very accustomed to Torx. I have actually begun to appreciate them

codrus wrote: So... why do they do it?

Look at the sensor in the OP. Those are procured from Bosch with the webbing around the bolt hole to add strength to the plastic. Do you think you could get an external hex into that little space? It is the same exact internal hex size as used on Bosch wheel speed sensors for exactly same reason.

Then, look down and to the right of it where there is a an area where there is enough space for a hex head on a in-house designed and manufactured part. What did they use?

I think we can probably mark this one solved.

Giant Purple Snorklewacker wrote:

codrus wrote: So... why do they do it?

Look at the sensor in the OP. Those are procured from Bosch with the webbing around the bolt hole to add strength to the plastic. Do you think you could get an external hex into that little space? It is the same exact internal hex size as used on Bosch wheel speed sensors for exactly same reason. Then, look down and to the right of it where there is a an area where there is enough space for a hex head on a in-house designed and manufactured part. What did they use? I think we can probably mark this one solved.

they could have used a bolt with a smaller hex head on it that uses a socket with an outside diameter smaller than the flange of the head of the bolt- and on that other fastener that you point out, they used a stud with a nut on it... kind of hard to do an internal socket or torx head on a nut. i guess they could have done a 12 point nut instead of a boring old hex nut, but costs become a consideration...

Giant Purple Snorklewacker wrote: Look at the sensor in the OP. Those are procured from Bosch with the webbing around the bolt hole to add strength to the plastic. Do you think you could get an external hex into that little space? It is the same exact internal hex size as used on Bosch wheel speed sensors for exactly same reason.

Put a little bit more materal on the part to raise the bolt head up to the level of the webbing, then use a normal hex-head bolt. Now you don't need all that specially engineered clearance outside of it because you can use a box-end wrench on the bolt.

The germans are still mad about the war...