Nerd bolts of the week

[Burnerman]

This is maybe of interest to those of you who intend to do some work on some VAG cars.....
Had to replace a rear hub bearing on a Seat Leon the other day (ABS light on, sensor fine so it was the magnetic reluctor on the bearing itself that had failed). The bearing and hub come complete.
The hub bolt is actually a 16mm spline bolt, and is ferociously tight. I was using a 16" Halfords Professional breaker bar, and couldn't shift it.....I supported the breaker bar and extension on a trolley jack and stood on it - promptly shearing the bar knuckle clean off
Fortunately a long pipe on a Britool ratchet managed to shift it, but I was convinced that those splines were about to strip - and then I'd be in real bother!
The caliper bracket also uses these spline bolts (14mm this time), again, fiercely tight and access was poor.
If you come across these spline bolts, heat them up if you can to soften the locking compound, and always drive them in to the bolt head before trying to undo them. If the splines strip, or the spline bit cams out you'll get hours of fun trying to shift them!
Have a good day everyone
John

 

[KingboyD]

Rear hub bolt factory torque is stupid!! 180Nm + 180deg!!!!! Last time I did one (on a MK5 Golf) I managed 180Nm + 90 deg before I decided something was going to snap

 

[Burnerman]

My concern was that the splines on either the bolt or the spline bit were about to shear.....then I'd really be up the creek minus paddle.
'That'll be a new hub, missus......sorry!'
John

 

[Dave54]

That 180Nm +180' sounds like madly (or something) tight. No wonder it's a pig to shift. I haven't seen one of these (I had a look on the web to see what the parts were like ) Another great piece of production engineering with little thought of future disassembly. Couple of things occur to me. Those ridged bolts on the front callipers of old Passats used to be awkward, as the hex was shallow and access awkward. I used to clamp a socket and bar on to the bolt with a big old G clamp I have for the first "crack" to get it started. Stops the socket camming off the hex. Might help here if there is access behind / big enough clamp?
Also would welding a socket on to the bolt through the socket drive square be strong enough if the spline in the hub bolt failed?

Finally I don't have a VAG car at the moment, and I only do my own, if I do get one in the future I'll nip up to Northumberland and get you to do it. Easier than doing it myself I reckon!

 

[Burnerman]

Nice to hear from you Dave!
Certainly this hub bolt was at the limit of my strength and its own, and you can imagine the relief when it finally started to give.
The spline hole isn't very deep, and the appropriate bits were rather a 'rattly' good fit (I have a Halfords Pro set and a Laser one - the Laser bit seemed to be the better fit of the two).
My thoughts were if I was to make a mess of this, maybe I could angle grind a couple of flats on the bolt head and shift it that way.....it is slightly recessed and I don't know if my welding would be good enough - also the ABS gear is close by. No matter - job done.
The caliper bolts were bloody tight too - and with the rust maybe taking the edge off the splines I thought the battle was to continue. Heat certainly helped there!
John

 

[Dave54]

Always nice to chat mate.

Anything that tight is always going to be a pain. Some of those hub nuts in general feel as if they need a 1" drive set and a tame gorilla to free them!

Those spline bits always seem a bit rattly to me too. I've got a "No Name" set that came from the local factors ages ago. The strength is fine, but I'd be happier if they were a few thou' bigger. I've got one odd Laser one and that does seem a better fit IIRC.

I don't know if my welding's up to that sort of thing either. It's one possible way out though. Whether it'd do for the ABS gear or not is another matter of course!

And a bit of "Charlie Warmington" (as an old mate of mine calls it) to free off sticky bolts is a life saver!