[A8] steel bolt in aluminum

[Kent McLean]

Rich, Jack wrote:
> I'm replacing my front axles, and the pinch bolt holding in the upper 
> control arms was a bear to get out on the passenger side.  The drivers 
> side is worse -- the head sheared off when I tried to spin it, and it 
> cannot be hammered out at all.  I'm going to have to drill it out.  
> But I can't help but notice that the bolt is magnetic, i.e. some sort 
> of steel, while the wheel bearing housing both looks like aluminum, 
> and is non-magnetic.
> 
> Do I have the correct bolt installed?  Is it supposed to be steel?

Jack,

I haven't seen much activity on the A8 list (this being the first posting I've 
seen in a while), so I'm taking the liberty of forwarding it to the V8 list (as 
I think they will have a vested interest as they move from their A8s) and the 
main quattro list (because there are a lot of knowledgeable people there).

A quick glance at the Family Album doesn't help, as it doesn't seem to give the 
materials of the items. For example, if I'm reading it right, Model A8Q, Year 
1998 (you didn't say), MG 4, SG 07, Illustration 407-10, shows bolt 27 as Part 
Number "N 101 312 03", "screw, hex. hd.", M10x105x32.

So, is it plausible to have a steel bolt in an aluminum casting? My guess would 
be yes, as an aluminum bolt would have to be real thick. But that's just a guess.

-- 
Kent McLean
1990 V8 w/5-speed and other mods
1991 200 TQA #3, with mods
1999 A4 Avant, V6 Tiptronic
gone: '91 200 TQA x2, '94 100 S Avant, '89 200 TQ "Bad Puppy"