<VV> was synthetic oil, now silicone brake fluid

[N. Joseph Potts]

If you mean to transit BACK to glycol-type fluid from silicone, you may be
in for some trouble (possibly more than when making the first transition). I
would hesitate, for example, to rely on mere alcohol to remove the silicone,
which I believe CAN interfere with the operation of the system with glycol
even in VERY small amounts.
     There IS such thing as silicone solvent, but it is hard to get/find AND
expensive. And of course, you'd have to replace all rubber in the system,
which it may be time to do anyway. I believe this transition CAN be done,
but I don't think I've ever heard of it being done. Done right, I would
expect the process to be pretty exacting, at least as to materials used.

Joe Potts
Miami, Florida USA
1966 Corsa coupe 140hp 4-speed with A/C and DOT 5

-----Original Message-----
From: virtualvairs-bounces at corvair.org
[mailto:virtualvairs-bounces at corvair.org]On Behalf Of Kirby Smith
Sent: Saturday, July 09, 2005 1:50 PM
To: VirtualVairs at corvair.org
Subject: Re: <VV> was synthetic oil, now silicone brake fluid


I can provide the following anecdotal information:

I last rebuilt my brakes about 25-30 years ago and put in DoT 5 fluid,
expecting the car to sit for a while.  It has unfortunately been on
jackstands ever since in my garage (definitely not dry in summer, but
lightly heated in winter, limiting temperature variation to about 50F).
  Now that I'm back working on it, I thought it was time to bleed the
brakes, which I did a few weeks ago.

I put a considerable amount of replacement DoT 5 fluid through the
brakes and none of the waste fluid showed water globules.  One brake
cylinder was found to have an incomplete bleed passage (no idea how it
got fluid in it to begin with).  When I removed the cylinder to
investigate why it wouldn't bleed correctly, there was no sign of water
pooled in the brake fluid, or corrosion on the cylinder walls.

The brake system does have teflon brake lines, but there is potentially
water transpiring rubber at the cylinder ends and in the dual master
cylinder cover.

Putting the car on the road could lead to other results.  Since I won't
be driving this car hard until the rings are seated once I get it on the
road, I will keep it DoT 5 until then, at least.

kirby
__