pulling an axle....90 cq

[isham-research.freeserve.co.uk at pop.pol.net.uk]

>> They are indeed allen head bolts, at least if audi haven't switched type.
>> But they are metric and the quality really sucks, audi has always used
>> really bad bolts for the drive chafts. Replace them with good quality bolts
>> if you can find them over there. Only use Audi bolts if you can't find any
>> good ones.

> Actually they are not the same as Allen Head bolts (6 Points). They are
> not Torx bolts either (8 points). They are Triple Square (12 point) and
> require a special internal wrench. Available at Pep Boys AutoZone etc.
> In sets of four,from 4mm thru 10mm if i remember correctly. Clean out
> the grit from the bolt head with a pick and then tap the wrench into the
> bolt head before applying any torque for removal. Works for me at least.

These bolts are made of some of the best steel on the car.

The reason they're triple square is that even Torx (itself vastly
superior to Allen) cannot be specified at this torque in a head so
small.  I use FACOM EV-208 and EV-210 drivers - the former in a FACOM
J.236 socket and the latter in a Draper 10mm driver socket.  I've
cemented both in place with epoxy because I got tired of them coming out
separately.  In my experience, triple square drivers are quite commonly
stocked in auto stores, but are usually labelled up for VWs, not Audis.
8mm for most if not all four-lug cars, 10mm by and large for five-lug.
Driver socket size is an issue - try and get a 3/8" driver socket for
the 8mm and a small 1/2" driver for the 10mm.  It has to be 1/2" because
of the torque, but a fat socket is hard to place against the boot.
Roger Galvin has an excellent set of drivers in which the bits are 1/2"
longer than normal - unfortunately he can't remember where he bought
them and they aren't marked.  Amazing, really - they're very good
quality.

Adding to the "scrape the bolt head out with a pick" comment above,
it's a good idea to flush the head out as well with some WD-40 or
similar - not to lube it, but just to wash out any debris.  Tapping the
driver home with a soft-faced hammer is essential - you can sometimes
need serious torque to undo them.  If you get just one sticking, undo
the one at the other end of its plate and shift the plate about a bit to
crack the seal.

The right driver, carefully placed, is the key to this job.

If the car is in the air, you'll need an assistant to stand on the
brakes.  I often use a yard broom, jammed between the brake pedal and
the headrest - it's more intelligent than some assistants.  Take it
out when you're done - you won't believe how fast the brake lights
can kill the battery.

Obviously cracking the seal on these bolts is much better done before
the brake caliper is removed ...

NEVER change these bolts for anything other than replacement approved
Audi bolts without taking serious professional advice.  There are
some pretty heavy warnings in the factory workshop documentation.  If
you check the way other fittings on the suspension and drive train
work, you'll find that most of them won't immediately fail if a nut
falls off - the design tends to stay together.  This is why the lower
ball joint clamp bolt has to be inserted from the back, for instance.
If you lose the hub retaining nut/bolt, the result will not be
immediate disaster.  But if the inner drive shaft bolts shear, you're
in trouble right away, proportional to the square of your speed at the
time.

-- 
 Phil Payne
 UK Audi quattro Owners Club
 Phone +44 7785 302803   Fax: +44 7785 309674