[6pack] DOT 5 leads to hydraulic component failures

[Jerry Shaw]

Thanks to all for your help.

Ibve been working on this TR6 for 9 years, finally enjoying it the past two.
Because of the long history, the rear brake and clutch system were exposed to
DOT 4 for a couple years, and obviously the master cylinders as well, although
all were either re-kitted or new while still using DOT 4 .  I then decided to
go DOT 5 over 3 years ago, since I had repainted the car. Ibve experienced 3
hydraulic failures with DOT 5, with the leaks coming after I had installed new
brake lines and flushed out the brake and clutch system by multiple bleeding
with DOT 5.

The first failure was a rear cylinder and I didnbt do a post mortem, just
replaced it with new. A post-mortem on a recent failed clutch slave cylinder
revealed no rust or potential DOT 4 water damage.

After doing some post mortem on the most recent rear wheel cylinder failure
just today, I now believe that there was some remnant of DOT 4 water damage
(prior to DOT 5) or absorption of DOT 4 in the rubber seals, since the
interior bore of the wheel cylinder was rust-pitted and rubber chards were
detected in the back of the cylinder.

With the help of this list, it is now my opinion that DOT 5 is not the
problem, but the mixed history of the use of water absorbing DOT 4 .

Jerry Shaw
b74 TR6 http://www.triumphowners.com/977