[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [New Search]

Re: Silicone Brake Fluid


On 2 Sep 98, at 11:42, Toby B wrote:

> Just to throw a wet towel in the ring,
> 	I used DOT 5 silicone (NAPA's, to name names) when I redid an older
> Datsun Roadster 5 years ago, and I was never really happy with the pedal
> feel.  It's a hard car to bleed, so I'm sure I never got all the air
> out, but even with S/S lines all around, the pedal had a really rubbery
> feel.  Not 'air bubble' rubbery, but 'dry rubber sliding on aluminum
> bores' rubbery.  I put DOT 4 in this spring, and have been much happier
> since.  Of course, this was a NON-TYPE-3 EXPERIENCE, but it really did
> happen!  

When I was looking into this many years ago, there were only two 
actual manufacturers of DoT-5, Dow-Corning and General Electric.
This may have changed by now, but there have always been many more 
brands than actual suppliers.

I believe you.  I don't know for sure what the cause of your 
observation was, but I believe that the compressibility of the 
silicone is not significantly different from std fluid.  I say this 
even though I understand that there are a million people out there 
who have heard otherwise.  I have also been through a car that I had 
a hard time bleeding properly, and I agree that it can certainly be a 
pain.

My experience is that each of us gets used to the feel of our brakes 
in our cars as they age and start to have problems.  One of the most 
common problems is frozen calipers, which means that the pistons 
don't retract as they are intended to.  One of the unexpected side 
effects of this is that our brakes get a higher pedal since the 
calipers have to go through less motion now that the pistons are 
usually already mostly in place.

So one of the first things people notice about their car after a 
brake rebuild is that there is "a lot" of pedal travel.  While this 
is perceived as a problem, in reality the brakes have just been 
returned to their normal, and proper, state.

I find that when I used the Girling LMA D0T-4 fluid, I could feel the 
MC rubber parts rubbing "squeaky clean" in the bore of the MC, and, 
sure enough, this rubbing caused the MC rubber parts to wear out in 
just a couple of years.  OTOH, the silicone fluid is such a good 
rubber to metal lubricant that these parts never seem to wear out.  
Yes there is a tremendous difference in feel, and I think it is 
wonderful.

Plus, the temp here gets down below -20F occasionally, and my brakes 
don't feel any different.  With std fluid the pedal felt like I was 
pumping molassas at that temp.

Jim
-
*******************************
Jim Adney, jadney@vwtype3.org
Madison, Wisconsin, USA
*******************************

-------------------------------------------------------------------
Search old messages on the Web!  Visit http://www.vwtype3.org/list/


[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [New Search]