thread/screw size

[photoboy]

Anyone know the thread size of the screws that hold the front disks onto the hub? I've found a company on ebay selling them but screwfix do a similar looking screw, was planing on changing disks/brakes this weekend. Screwfix is 5 mins from me. Thanks in advance.

Link/pic of ebay screws

http://tinyurl.com/c534bxq


Link screwfix screws

http://tinyurl.com/bpsytwv

[geoff]

I would just take one of the screws down to screwfix and get them to match it up, that way you'll get the job done this weekend. I doubt the postman will get the Ebay screws to you by this weekend.
I'd guess on M6 but don't quote me.

[photoboy]

I would just take one of the screws down to screwfix and get them to match it up, that way you'll get the job done this weekend. I doubt the postman will get the Ebay screws to you by this weekend.
I'd guess on M6 but don't quote me.

I'm going to have to drill he screws out, as their never coming out.

[evdama]

Generally a 5mm Allen key fits an M6 Screw.Get some coppaslip while youre there too...

[pidgeonpost]

I'm guessing here, but if the screws pass through plain holes in the disc you may be able to drill the heads off the screws. Is that what you had in mind? If that's the case then you should be left with the stubs of the screws sticking out of the hub once you lift the disc off. You may then be able to use Plus Gas/heat/Mole grip to get the stubs to shift. Maybe you can beg or borrow a set of stud extractors?

If you really still can't shift the screw stubs you will, as you say, be faced with drilling the blighters out. Trouble is that you'll have to be very lucky to be a good enough shot with a hand-held drill to follow the axis of the screw. If you drift off course you'll damage the threads in the hub, though they may clean up OK if you can run a tap through them.

There are other work-arounds, but let's not go there yet!

When you get the old discs off give the face of the hub a good clean off to remove any rust scale or muck otherwise the shiny new disc may run out of true giving you judder when you brake or steering shimmy.

And definitely go with the Coppaslip as evdama says.

Good luck - sounds like you have a fun weekend ahead!

:thumbsup:

[jericlin]

Had just the same problem. No motor factors including ECP could supply them and referred me to Citroen. ( they had none in stock )
Got a set of SS ones ( 10 in a bag ) on eBay for not a lot. Didn't arrive in time and old ones drilled out. Good S/H used in meantime and will be replaced with the new ones soon. In reality they do little other than line up the disk to hub holes for wheel fitting. You could drill out C/S part leaving stub then remove disk and fit new one as only the hub has thread tapping. Why they should be " special " is hard to say, could be thread, diameter , length , countersink angle , counter sink depth , who knows ( at least one ebay seller does ) easy way to keep holes lined up - fit wheel bolt through disk to hub, apply brakes and keep applied, remove bolt fit wheel with all bolts, release brakes. Tighten up wheel bolts
Ask and I will dig out ebay info.

[evdama]

I'm guessing here, but if the screws pass through plain holes in the disc you may be able to drill the heads off the screws. Is that what you had in mind? If that's the case then you should be left with the stubs of the screws sticking out of the hub once you lift the disc off. You may then be able to use Plus Gas/heat/Mole grip to get the stubs to shift. Maybe you can beg or borrow a set of stud extractors?

If you really still can't shift the screw stubs you will, as you say, be faced with drilling the blighters out. Trouble is that you'll have to be very lucky to be a good enough shot with a hand-held drill to follow the axis of the screw. If you drift off course you'll damage the threads in the hub, though they may clean up OK if you can run a tap through them.

There are other work-arounds, but let's not go there yet!

When you get the old discs off give the face of the hub a good clean off to remove any rust scale or muck otherwise the shiny new disc may run out of true giving you judder when you brake or steering shimmy.

And definitely go with the Coppaslip as evdama says.

Good luck - sounds like you have a fun weekend ahead!

:thumbsup:

A trick that sometimes works is attempting to actually tighten the screws first.
Sometimes the tiniest movement is enough to crack the crust while keeping the heads drive surfaces ok for the anticlockwise direction afterwards.
Obviously the tapping size for M6 internal thread is 5.0mm so dont drill any bigger than that

[photoboy]

Thanks for the replys guys, I had a look at the screw the other night, the garage who changed the disk the last time have damaged the screw that is currently fitted, it's made of a very soft metal, so my plan was to just drill it out. I'll post up the screw size when I figure it out.

[Rustscrat]

Hi, 6mm x 14mm Countersunk. There are used just to locate and hold the disk in position while you fit the brakes etc. They don't have to be that tight (10Nm) as it's the wheel bolts that clamp the disk. :thumbsup:

[pidgeonpost]

When considering metric threads it's worth remembering that there are two in common use - metric fine, and metric coarse. They will almost certainly be metric coarse on your hub.
As these screws are rarely removed and replaced it's unlikely that the thread will be in bad shape, but if you want to clean the threads out and don't have a tap you can cut a slot in the end of a spare bolt/screw with a hacksaw and use that as a 'tap'. Put a smear of grease in the slot and any rust or muck will be collected in the slot you've cut. Take it easy when using it though - no more than a full turn clockwise, then half a turn back, as cutting the slot will weaken the screw and you really don't want to break it off in the tapped hole.
Ah! The memories of grovelling under a wet vehicle in semi-darkness trying to undo seized components come flooding back! Thank God I don't have to do it any more! Well, not if I can help it anyway!
Good luck!

:thumbsup: