Drive shaft bolts

[Corderoy]

I'm in a bit of a bind regarding the size of the spline bit to fit the drive shaft bolts.

I got onto the area Snap-On guy and he broke a kit to supply me with an M8 bit (8mm) and also a M12 (12mm) bit for the head bolts.

When I tried the M8 for size it was too big.

Got back onto the guy and he kindly agreed to swap for an M6 which is very close to the size of the torx plus bit which almost fits.
Brought that home and the bloody M6 is too small... it spins freely in the bolt head!

Bugger! Got the verniers out and measured the bolt head spline socket and it's 7mm.

Got back onto the Snap-On guy (we're old friends by this stage) and he doesn't list a M7 :(
He checked the kits he had and each of them go from M6 to M8.
That is also the case with the kits I've found online.

I've found references on here regarding M8's for the drive shafts so I'm assuming I don't have the only Seat in the known universe with M7's.

So given that I hadn't even heard of "spline" bits until a few days ago I'm a bit lost as to what is going on.

Any thoughts as to how I confirm what is what?

Pic included in case I'm talking about different bolts to everyone else

http://www.vwwatercooled.com.au/forums/images/imported/2009/02/Splinesocketbolt-1.jpg

[william]

i changed one on an ibiza gti and they were m8 multispline bolts
try lining it up and taping them in slightly.

[Corderoy]

i changed one on an ibiza gti and they were m8 multispline bolts
try lining it up and taping them in slightly.

Cheers mate, thanks for quick reply.

There's no way the M8's will fit... they don't come close. I measured the spline in the bolt head and it's definitely 7mm.

I guess I'm after confirmation that the pictured bolts are what are supposed to be M8's and from there I'll have to find an M7 spline bit :(

Do you know if "spline", "three square" and XZN's are the same thing?
I don't know for sure but as the Snap On bits are XZN's and the 12mm one fits the head bolts perfectly, I assume it's different names for the same thing?

[william]

dude i have three different bit sets in my box and not one has an m7 do they produce them?? get multis or a chisel and hammer to get them out atleast. btw i have a 2l long end shaft for sale near new for $50

[Corderoy]

No idea.

I 'spose I'll find out tomorrow, lol.

I found one reference (can't rem whether it was specifically M7) to spline sockets that are supplied only to certified VW repairers.

Anyhoo, the car isn't going to be sitting in the shed forever so something will have to happen ;)

[william]

usually those bolts are known to sheer off under heavy abuse as mine did on that gti i could turn two out they were that loose lol goodluck with it

[Corderoy]

i could turn two out they were that loose lol goodluck with it

Yeah thanks mate. I'll get 'em out one way or another but I'd prefer to start with the easy method ;)

[gtimk5]

I have been working on VWs ect. for well over 30 years and I have never had the need for an M7 multispline!! Your CV bolts are definately M8 and quite often you get dirt and rubbish in them. It pays to pick around inside them with a small screwdriver first and gently tap the socket into the bolt. New Snapon sockets are a firm fit, but when you use them in the trade constantly they wear pretty quickly which can cause "rounding out" of the splines in some cars. I am always keeping mine refreshed with new spline sections of the socket.

[Tim]

as above. Its most likley full of crap. Give them a good clean out

[Peter Jones]

M8 Trisquare for sure, I've pulled a few of hose boxes. http://www.vwwatercooled.com.au/forums/images/imported/2009/02/50pxScrew_splinesvgpng-1.jpg I don't think there's such a thing as an M7.

As above just tap it in, I usually give the bolt heads a blast out with degreaser and compressed air if they're gunked up.

Wikipedia says this -

Triple square, also known as a XZN socket, is a type of screw drive. They are commonly found on German (http://en.wikipedia.org/wiki/Germany) vehicles (http://en.wikipedia.org/wiki/Vehicles) such as BMW (http://en.wikipedia.org/wiki/BMW), Mercedes (http://en.wikipedia.org/wiki/Mercedes-Benz), and Volkswagen (http://en.wikipedia.org/wiki/Volkswagen)[1] (http://en.wikipedia.org/wiki/Triple_square#cite_note-0). These screws are used in high torque applications such as cylinder head bolts and drive train components. Triple square bolts are common to early Porsche (http://en.wikipedia.org/wiki/Porsche) and Volkswagen constant velocity joints (http://en.wikipedia.org/wiki/CV_joints).
Common sizes are 6, 8, 10, and 12 mm. Triple square drivers can be purchased at auto parts stores and through automotive tool distributors.
Increasingly, triple square screws are found on other European and Asian makes of cars.
Other names for triple square screws and drivers are "Double Hex", "Double Allen", and "Aircraft Screws". Despite this, "Double Hex" and "Double Allen" are misnomers (http://en.wikipedia.org/wiki/Misnomers). The recess in these bolts is actually (as the name suggests) made of three squares, not two hexagons. The corners are 90 degrees, not 120 degrees. They are not double hexes (http://en.wikipedia.org/wiki/Double_hex), and an Allen key will not fit them properly.


Pete

[Golf Loon]

They are M8 mate.
I get a long bar and the socket and sit out by the wheel and then tap em in with a hammer.
This seats em and loostens the bolt.

[Mischa]

lol i agree with the above. no such thing as an m7 afaik.

you'd be wise to believe the people above this post, lots of experience there :)

[brad]

When I did my clutch I'd never heard of triple square sockets..... so I butchered them out with an allen key & vice-grips. Not recomended as it added at least an hour to the job & then I had to source new bolts (got some HT Allen heads).

I would have got the right tool but the manual that I had showed them as an Allen Head.

[Corderoy]

Thanks guys...

Yeah, I'm very happy to listen to the voices of experience :)

Nothing else makes any sense.

I did clean the splines of the bolt I tried to loosen (and measured) but I I didn't try to tap the bit in.

I'll swap again with old mate Snap On and try it again.

I'm sure you're right... maybe I'm just being overcautious with regard to damaging them.

Cheers...

[DVR68U]

its not a allen key head and not a spline head. its a triple square (+other ones pete said) head bit. thats why yours didnt fit you must have had the spline in 8mm which is different. go for a tripple square . there sometimes hard to find in shops but once you have it you can use it again many times over. thats the good thing with buying tools. plus always try to use the right tool for the job. and that never includes a shifter lol ;)
cheers brenton

[Mischa]

its not a allen key head and not a spline head. its a triple square (+other ones pete said) head bit. thats why yours didnt fit you must have had the spline in 8mm which is different. go for a tripple square . there sometimes hard to find in shops but once you have it you can use it again many times over. thats the good thing with buying tools. plus always try to use the right tool for the job. and that never includes a shifter lol ;)
cheers brenton

i was under the impression a spline is a triple square??

[Corderoy]

its not a allen key head and not a spline head. its a triple square (+other ones pete said) head bit. thats why yours didnt fit you must have had the spline in 8mm which is different.

Thanks for that, Brenton.

That makes it a clearer for the struggling old brain.

I just measured the XZN '12' I got from Snap On and it is actually 11mm across the splines.

If that convention holds true the XZN '8' that I had (and should have again this arvo) must be 7mm across the splines which is what I measured the internal head spline to be.

That being the case it will fit.

Call me presumptuous but I have always thought that M8 meant "Metric 8mm".

As the haze of confusion clears I'm getting a lot more comfortable with the whole thing now :)

edit: Just phoned the Snap On guy and got him to measure the XZN '8" and it is indeed 7mm across the splines. Sorry for the storm in a teacup guys but I've certainly learned something from it.

edit2: As a by the by, I measured the XZN '6' and it is in fact "6mm", lol.

[Peter Jones]

I suspect you're not measuring them correctly.

My recollection is that an M8 is 8mm between opposite corners of any of the three squares. If you're using verniers to measure, rotate the tool to make sure you're reading at the widest point. Same logic applies to the other sizes.

Bear in mind that the tool is most likely slightly tapered too, you might need to take the measurement further up the shaft.

Tri-square and xzn are the same thing.

Spline, allen, double hex, torx, polydrive, bristol are all very different things although they might look similar.

I have a set of bristol bits but I've never found a use for them. Anybody actually seen these in the wild? I think these are also called RIBE bits.

I'll measure mine up tonight, I'm kind of curious now.

Pete

[gtimk5]

Ok, I will leave it up to you fellas to figure out the size.........:duh:

[Mischa]

apologies for saying that splines and triple squares are the same. wikipedia has schooled me!

[Corderoy]

I suspect you're not measuring them correctly.

Fair point, Peter

Across the points and 2/3 up the spline of the '12' I make it 11.5mm - which is reasonable allowing a clearance in a 12mm socket.

Same distance up the '8' I make it to be 7.1mm or maybe 7.2mm


I'll measure mine up tonight, I'm kind of curious now.

Always happy to hand out homework :)