Brian, you undoubtedly have bad seals in the MC which allows backflow. I
have successfully used rerbuild kits, but if the bore is shot, get the MC
resleeved at White Post restorations, its much cheaper than a new -one, and
they use stainless steel.
From: LANOWAY, BRIAN <Brian_Lanoway@Standardaero.ca>
To: 'Triumphs Digest' <triumphs@autox.team.net>
Subject: TR6 sinking brake pedal
Date: Monday, July 07, 1997 9:19 AM
Hi List:
Isn't it amazing how our LBC's fall apart even when they stand still.
I need some help with a braking system problem on my TR6. I noticed
that a similar problem was raised last week but there's been no
response on that problem so far.
On an intermittent basis, my brake pedal will slowly sink two thirds
of the way down to the floor when steady pressure is applied. On
other occasions, it doesn't sink at all. When it does sink, it does
pump up with one stroke and then seems to stay up for a fair while.
I've bled both the front and rear brake circuits and found very
little air in them. I'm not losing any fluid from the master cylinder
and there's no evidence of brake fluid anywhere, including the floor
of the driver's area. The brake system is currently filled with
"Kleenflo" fluid - which is silicone based. I should point out that
this sinking feeling started after 6 months of winter storage.
Any ideas? I have a troubleshooting guide from "Motorhead" that
indicates that the English rubber seals in the braking system rot when
silicone based brake fluid is used. Has anyone else found this to be
the case? If it is the brake master cylinder, Motorhead advises
against a rebuild - indicating that rebuilds usually fail. Instead,
they recommend replacing the master cylinder which is a very pricey
option (Motorhead also sells TR6 parts). Any advice on this, if it is
the master cylinder? Could this be something else, like the brake
servo assist?
Has anyone else encountered this problem and cured it? Are there any
tests that I can conduct to isolate/pinpoint what the problem is?
Thanks in advance,
Brian Lanoway
73 TR6
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