Brake pedal sometimes is low on first
press but otherwise is always high
> I went to an autocross last Sunday.
Thought it would be fun to let my
> buddies see me slide around on the brick-like tires it is
> I launched, then made a few turns, accelerated, changed up
to second. Then
> I needed to use the brakes for the first time on the run.
The pedal dropped
> more than half the travel. The brakes worked fine, but it
felt really weird
>having such a long stroke to get to them. Scared me half to
death the first
>After the run, the brakes pumped right
up. Checked the reservoir. Fluid
>full, as normal.
>Brakes worked normally in the marshaling
lane and all the other times
Reply from: Jack W. Drews
I had the same problem with my TR4 vintage racer. It took three
years and trying LOTS of things before we finally tumbled to
the root cause. On the way to the
solution we tried everything -- including aftermarket residual
for the front circuit.
Something is happening with the front wheels to push back the
pistons in the calipers during cornering. With my car, this happened
only after a
left-right-left sequence of corners.
It could be loose wheel bearings, but that was not the case
in my car, and is
apparently not the case in yours. You could check to make sure
that the nut
holding the front spindle in the upright is still on tight. They
have been known
to loosen, hard as that is to imagine. In my case, the cause
was that the rotors
had been turned a couple times and were under spec on thickness.
solved the problem with new rotors. I have since found on my
car that this
problem will start with any irregularity in the rotors -- taper,
flatness, etc etc.
NOTE FROM TERIANN:
As Jack mentioned, low brakes on on a first
push can be caused by the front wheel bearings being set too
loose, which they will be if you follow the instructions in
the TR3 shop manual. The published instructions are for
the early drum brake TRs. Triumph issued a service
bulletin that provides instructions for
adjusting wheel bearings on disk brake Triumphs. Also
be aware that the current felt pads are initially thicker than
the old ones and will compress with use. After
replacing the felt pads it is a good idea to go back and reset
the front hub bearing clearances after about a 100 miles.
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