Combined Allen hex bolts

[sarkie83]

I've been changing the cambelt on my arosa and the waterpump is attach by 3 hex bolts that also have an Allen insert. Like this:



Seems like a good idea -as if they get rounded off, you've got another way of removing it. I've tried searching around but can't find any generic alternatives. Anyone ever come across them?

[Rich]

I would imagine if they are tight enough to round off the main outer hex they are going to be too tight to undo with an allen-type key so I wouldn't waste too much time looking for them. I've only ever seen them as fitted OE on stuff.

[steveo3002]

bit of a strange idea...wonder whats thats about

cant be incase you round off the allen key bit , not like its bothered them on the 1000s of other fastners they fit

and why go to the cost of making it like that if a normal spanner/socket works anyway

[luckyseven]

Never understood this idea for the very reasons already mentioned. Mazda have a hbit of doing it, especially with bodywork fasteners only they put a cross-head screwdriver slot into the hex head which is even more pointless than an allen key one. To be fair, I've never got to round one off because the bolt head generally shears off long before it rounds

[lufbramatt]

They probably assemble it with the allen hole in the middle on the production line, but you need to use the external hex to break the threadlock on disassembly.

[usedabused]

An allen / alan type bolt is a cap head..

Car manufacturers spend as much on designing fasteners as on any other car component and key features are capability cost weight and application on a production line..

The funny shaped heads on automotive fasteners are a result of this..

[MrSpeedy]

They should stop trying to reinvent the wheel and concentrate more on making decent reliable cars

[colnerov]

Hi, They do it to make the car quicker and cheaper to assemble in the factory. They don't care how difficult it is for the owner to fix it, in fact they don't want you working on the car. They are trying to protect the main stealers who pay a not inconsiderable amount of money to be one. They also don't want the car to be too reliable that you don't have to replace it, but not so unreliable that you don't return to the brand.

Colin

[melle]

Bet the workshop information system states you need a special tool to undo them.

[93fxdl]

The technical term for making products not last too long is, technical obsolescence, it used to be rust that killed cars, now It's usually warning lights that condemn an otherwise ok car to the breakers
Ttfn Glenn

[melle]

What's that to do with funny bolt heads?

[93fxdl]

Funny bolt heads are part of the non user friendly systems, where you have to buy special tools to do the most minor service items, also there are self feeding tool systems which use funny heads to speed production.
Ttfn Glenn

[melle]

I don't have the impression these bolts inhibit DIY repairs in any way as they can be removed with generic tools and replaced with off the shelf standard bolts if needed. My first post in this thread was only meant as a joke.

[truckdoctor]

Aug 24, 2016 20:12:07 GMT sarkie83 said:

I've been changing the cambelt on my arosa and the waterpump is attach by 3 hex bolts that also have an Allen insert. Like this:



Seems like a good idea -as if they get rounded off, you've got another way of removing it. I've tried searching around but can't find any generic alternatives. Anyone ever come across them?

I came across these fitted where they were in close proximity to other moving components, they are "low profile" the internal hex adds to the outer hex surface area allowing them to be torqued up with out rounding over. They are inconvenient and require the correct tool that was in my case un-available and ended up removing a complete trans axle assembly to chisel them off. Good luck