[Vwdiesel] front brake rotors (fwd)

Thu May 10 09:48:09 PDT 2012

The truth is I own at least a half dozen air chisels, but the tools I use
more on rusty fasteners are air impact and torch.  I live between Rochester
and Buffalo and we get our share of salt.  Some fasteners rust after one 
season.  I learned years ago, and periodically relearn, that using a 
conventional wrench is an invitation for things to break.  

Recently I saw the local garage mechanic tugging and breaking brake bleeders.
I loaned him my mouse (3/8" butterfly impact tool) and explained how to use
it, and a week later he had one and told me he wasn't breaking bleeders 
any more.  

I agree with James that an air chisel is great, impact wrenches are better
(this will be the issue we fight over).  And torch is best.  Here is why:

Rust is a matrix of iron oxide.  Oxides of metals are harder than metals,
and more brittle than metals.  So the structures tend to "bite" into softer
metal when a fastener is turned.  Impact causes mechanical failure of the 
oxide structures, and breaks up the rust matrix.

The brake rotor retainer bolt is a perfect example of the use of heat, because
with a small tip, one can heat the screw, and the thermal mass of the rotor
is great, therefore it heats slowly.  The hot screw expands in diameter,
crushing the rust, and when things cool, a impact tool or even a screwdriver
can be used to walk the screw out.

James is also correct when he suggests that we underestimate the value of 
mechanical impact.  I used a trusty breaker bar on the other side of the 
aforementioned Dewalt impact tool, and after 5 seconds, it fell apart,
with the parts (ball, spring, pin and 3/8" element) falling all over the place.
I've had that breaker bar for 40 years, and never was there any hint of 
it coming apart.  

James also makes a good point on the ARP tools, however, in my recent 
re-tooling, I decided to go LiIon, and in general that it a good path,
especially for those who infrequently use tools (better long term charge 
retention) but I would avoid them if your shop gets to -40C/F as LiIons
do not fare well those temps.  I have both, but buying new, LiIons are 
my choice.

Thanks for reading, and I'm glad we can make so much about a simple
rotor retainer screw.

Forwarded message:
> 
> And just to add to the pile, I would highly recommend buying a cheapie air
> chisel- if you have an air compressor that is...
> When you get one,  if there is no punch that is the same diameter as the
> chisel shafts (1/2 to 5/8" or so), immediately kill one of the mostly
> useless attachments that come with it by cutting off the end, so you have a
> blunt, broad faced punch.  In all my years of being a shop rat, there is
> NOTHING as effective as the vibration of an air hammer to loosen stuff up.
> Absolutely nothing.  An example- this spring I'm fixing the hopper trailer
> chutes- and had to cut remove a sprocket that opens the chutes- this thing
> has been in fertilizer, road salt, and is seized to the 1.25" shaft.
> Sprocket has a nice step in it, I could grab it with a puller- and promptly
> pulled the step off, didn't move the sprocket. Used heat, na da.  Touched it
> with the air hammer, with the big flat punch end, and it skitters off like
> it's machined to a slip fit, unscathed, I could reuse it even after touching
> up the step thing I killed.
> Frozen ball joints, tie rods, bolts, collars, bearings, you name it, it
> never fails to buzz right off, even the threads on those stupid GM split tie
> rod adjusters, the ones with the split in them so they retain maximum salt
> and rust.
> 
> Oh, and a note on Dewalt tools. I have the same 18V impact as Val, and
> drill, nut driver, etc... There are two distinct lines of batteries- 
> Buy the XRP ones if you can, and sometimes the tool is coming with an XRP
> (9096), sometimes with the not XRP (XRR?) which has half the Ahr rating of
> the XRP. If it doesn't say XRP on it, it's about half the capacity, and waay
> cheaper. Pretty good tools in the XRP line, had mine for 5 years already,
> just had one battery pack go south so far.
> I got 5 XRP batteries this winter for 40 a pop on ebay, so look around. They
> are 90 on sale at Depot here.
> -james
> 
> 
> 
> -----Original Message-----
> From: vwdiesel-bounces at vwfans.com [mailto:vwdiesel-bounces at vwfans.com] On
> Behalf Of Val Christian
> Sent: May-09-12 7:38 PM
> To: vwdiesel at vwfans.com
> Subject: Re: [Vwdiesel] front brake rotors (fwd)
> 
> Impact and heat are the way to go.
> 
> 90% of the time, I just use a screwdriver bit with the "mouse" (hand held
> 3/8" impact tool (NOT air ratchet)).  If I have a really snarly one, I heat
> it with a medium (for me, which means about 6 cu ft sized) oxy acetylene
> flame, let the head get red and then let it cool.  Most of the time, I avoid
> putting the screw back in, or I put it in with neversieze, which I am not
> sure really helps.
> 
> Like Loren says, you can use the hammer type impact tool, and if you don't
> have any impact tools, you should get one of those.  Usually they come with
> 3/8" hex bits for screws (slotted and phillips) and will drive 1/2" sockets.
> In my poor starving student days, I wore out one of these, on the cam,
> mostly working on my wife's Volvo.  Got rid of the Volvo and got better
> tools.  The replacement still looks new.
> 
> BTW, I have one of the LiIon Dewalt impact tools, and did wheel lugs with it
> the other night on a Jetta.  Wow.  Before you buy one, look at the torque
> rating, as there are several different torque ranges, and what works well
> driving lag bolts on a deck, might not be awesome enough to do wheel lugs.
> I used a Snap On one several years ago, and these tools, when sized right
> for 150 ft lbs or so, are really handy.  I imagine that rally crews use them
> now, but don't know for sure.
> 
> 
> 
> 
> Forwarded message:
> > 
> > Sometimes lining things up can sure be a pain in the butt, so it would 
> > be w= orthwhile to attempt to remove the screw intact.=A0 I seat the 
> > screwdriver = and then hit the handle of the screwdriver with a 
> > hammer.=A0 I learned a tr= ick of giving it 200 sharp hits, at the 
> > rate of approx 100 per minute.=A0 T= hat shock/vibration does a pretty 
> > good job breaking up rust and corrosion t= hat will likely be 
> > present.=A0 Spray it with PB Blaster before starting, ha= lfway 
> > through, and at the end.=A0 =
> > 
> > 
> > If the screw doesn't turn easily then, I will clamp locking pliers 
> > onto the=  base of the handle of the screwdriver.=A0 This allows me to 
> > lean on the sc= rewdriver with full pressure, and turn it at the same 
> > time.=A0 At that poin= t, it should either turn easily, or snap 
> > off.=A0 Either way you can change = your rotors.=A0 =
> > 
> > 
> > =A0
> > Dave Cook
> > 
> > 
> > ________________________________
> >  From: Travis Gottschalk <tgott at hotmail.com>
> > To: vwdiesel at vwfans.com; db53248 at windstream.net =
> > 
> > Sent: Wednesday, May 9, 2012 4:34 PM
> > Subject: Re: [Vwdiesel] front brake rotors  =
> > 
> > 
> > It is the largest one you will be able to find at a store. Sometimes 
> > they a= re rusted on and you have no choice but to just break 
> > off/drill out. Not ne= eded for install but it is nice when you put 
> > your wheels on to keep everyth= ing aligned. =
> > 
> > Travis G
> > > Message: 6
> > > Date: Wed, 9 May 2012 05:40:32 -0500
> > > From: "Pam & Doug Boes" <db53248 at windstream.net>
> > > To: <vwdiesel at vwfans.com>, <vwpickups-request at neubayern.net>
> > > Subject: [Vwdiesel] front brake rotors
> > > Message-ID: <001201cd2dd0$295890d0$7c09b270$@windstream.net>
> > > Content-Type: text/plain; charset=3D"us-ascii"
> > > =
> > 
> > > What is the size and pitch of the flathead Phillips screw that holds 
> > > the front brake rotors in position on the early 80s Caddy's or 
> > > Rabbits =
> > 
> > =A0=A0=A0 =A0=A0=A0  =A0=A0=A0 =A0  =A0=A0=A0 =A0=A0=A0 =A0 =
> > 
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> 
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