[6pack] DOT 5 leads to hydraulic component failures

[Greg Lemon]

I did essentially the same thing as Lou describes on my Austin Healey and 
drove it for many years afterwards with no problems, on the TR250 I started 
with all new parts and used Dot 5, no problems there either.  I tried to 
post to this topic earlier, but don't think it went through.  I have been 
driving brit cars for a long time, about 35 years, in the old days I had 
regular issues with this or that slave cylinder leaking or seeping past the 
seals, couldn't say exactly how often, but happened more times than I can 
remember, maybe once every year or two.

Since going to silicone about 10 years ago I don't believe I have had any 
issues whatsoever with leaks, hard to remember for sure that far back, but 
know I have not had issues for many many years.

--------------------------------------------------
From: "Lfmaol" <lfm614 at aol.com>
Sent: Sunday, February 10, 2013 11:00 AM
To: <6pack at autox.team.net>
Subject: Re: [6pack] DOT 5 leads to hydraulic component failures

> I respectfully disagree with the need to flush with alcohol. The reason I 
> say
> that is that I have been running DOT5 in a previous DOT3 system without 
> the
> alcohol flush for almost 4 years now with no problems what so ever.  I 
> rebuilt
> both master cylinders and clutch slave but not the wheel cylinders or 
> calipers
> as they were/are working great with no leaks, sponginess or binding.
>
> After reading a very good article on Buckeye Triumphs about fluids when I 
> was
> doing this, I decided to just replace the 3 with 5.  They don't mix at 
> all.
> If you put both in a jar, they will stratify in less than an hour with the
> DOT3 (and water) on bottom.   So what I did is I flushed the DOT3 with 
> DOT5 by
> bleeding the brakes starting from the furthest wheel first, etc. until I 
> saw
> dark purple fluid at all four corners.  After about 100 miles and 2 weeks
> later I repeated the process and got the rest of clear fluid which was 
> minimal
> out.
>
> I believe that if you are not very careful to flush just the lines and use 
> new
> rubber you can more damage that good by exposing the rubber seals to 
> alcohol.
> Look what E15 is doing to fuel lines and seals and why most car 
> manufacturers
> today say it will void the warranty to use it and that's only 15% alcohol.
>
> I think that the best thing you can do to ensure success during rebuild is 
> to
> use abundant Girling or other rubber grease to coat the seals and reduce
> friction, it will last as its not soluble to DOT5.  Also be real careful 
> when
> buying new masters and cylinders as there are lots on cheap imitations out
> there of not the best quality. This is why I prefer to rebuild unless 
> there is
> substantial pitting and so far I have had good luck with that approach.
>
> Not arguing, just presenting a different opinion from someone that's been
> there - done that.
>
> Here is the Buckeye article if anyone wants to read it :
> http://www.buckeyetriumphs.org/technical/Brakes/Fluid/Fluid.htm
>
> Lou
> 72 Pimento