Date:         Sat, 13 Jul 2002 21:06:05 +0100
Reply-To:     Clive Smith <clive.harman-smith@NTLWORLD.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Clive Smith <clive.harman-smith@NTLWORLD.COM>
Subject:      Rotor (disc) seizure on hub
Content-Type: text/plain; charset="iso-8859-1"

Correction to my last (badly worded) post - Clive
I think when you says rotors, we call them the discs (of a disc brake) in the UK

I think when you say anti-seize (compound) there might be many types and styles of this. As far as discs seizing in a hub rebate/ shoulder....
To avoid this type of corrosion seizure, particularly between dissimilar metals - the aircraft industry uses something called chromate compound; its a yellow paste and I beleive it contains zinc (maybe zinc chromate then).
One name I remember was JC5A (maybe an a/c industry spec.) jointing compound, I bet that'll slow it up a
bit, but then I don't know ehere to get it from now .
Wahtever you used that didn't seem to work for long, it must disperse, exclude or emulsify water vapour and prevent electrolytic potential between dissimilar metals, even if they both appear to be steels) of different alloy compostions.
Failing having anything else to hand, I think I'd also be inclined to use the anti-seize compound that is normally supplied and used liberally on the back of the disc pads, although the clearances here are somewhat larger and constant movement does occur.

Clive Smith
'88 Syncro Transporter

----- Original Message -----
From: "Richie Chunda" <Richiesbad@AOL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, July 12, 2002 7:01 AM
Subject: Re: No Subject


> In a message dated 7/11/02 11:40:21 PM, jcessence@HOTMAIL.COM writes:
>
> << I am trying to remove the rotors on my 87 syncro...   ... Does anyone
have
> any ideas? >>
>
> John,
>
> I have been through the misery which is now staring you in the face more
than
> once.  First, I will tell you what I found to be the source of the
problem:
> there is far too little clearance between the OD of the hub flange and the
ID
> of rotor.  I would guess this gap is about .030".  Whenever the ID of the
> rotor rusts, the exfoliating iron oxide fills this scant space solid and
the
> rusty rotor becomes one with the universe and, unfortunately, also the
hub.
>
> The first time I was confronted with this problem, I saturated the rotor
with
> penetrating oil, applied some heat and went at it with a 2 lb. copper
hammer.
>  After some abuse, it came off.  At the time, I did not realize that I
was,
> in some small way, lucky.  More about that later.  I saw what the problem
was
> and as I mounted the shiny new Brembo's I thought for sure by painting the
> mating surfaces with anti-seize that I would not get stung again.
>
> When it came time to renew the front wheel bearings, the anti-seize
slathered
> Brembo rotors would not even budge.  In the end, I removed the rotors with
> the hubs still attached.  The rusting was much worse than before.  I
descaled
> the rotor/hub joint as much as possible with every kind of pointed tool
> imaginable, then I soaked the assembly with penetrant and tried to press
them
> apart on my small press.  At the point that it appeared something might go
> bong and drop my sorry ass into a carefully dug hole in the ground, I
decided
> to try a different approach.  I placed a piece of plywood on the floor
with
> the rotor/hub (inboard side down) on it supported by a few blocks of
> hardwood.  I then heated the collar of the rotor with a rosebud tip in an
> oxyacetylene torch.  I wanted to heat the rotor as quickly as possible so
> that little heat would soak into the hub.  As soon as I thought it was hot
> enough, I held a 6" length of 2" AL round on the center of the hub and
gave
> it one hell-of-a smack with a heavy hammer.  It finally popped out.  In
> hindsight, I should have wasted away the rotors on the lathe; it would
have
> been quicker.
>
> Before, I mentioned that I was lucky the first time.  I was lucky because
the
> original rotors were OE and they rusted far less than the Brembo's.  When
I
> unpacked the Brembo's, I was duly impressed with the machine work on them.
> What I could not see was the metallurgy in them.  As pretty as they were,
I
> have never seen rotors rust to that extent.  So, if you have aftermarket
> rotors, you might have to cut them off.  Keep in mind, that the edge of
the
> hub flange is almost hard against the ID of the rotor.
>
> I have heard some guys talk about beating on the rotors until they break
> apart.  Given a big enough hammer, I guess anything is possible, but it
will
> also ruin your wheel bearings while you are pounding away at it.
>
> Although Syncro OE wheel bearing last a long, long time, if you think
yours
> will need renewed soon, now might be soon enough.
>
> Richie