Last week I posted some questions about grinding when shifting from 3 to 4
with O/D on. (No grind when O/D off during the same shift and no grind
during 4 to 3 shift regardless of O/D state). I also mentioned that I had
recently made changes to the clutch linkage. I received numerous replies and
suggestions on what could be causing it (including the suggestions that it
is normal for TR6 J-type O/D's to grind during the 3-4 shift). As well, I
posted that pressure test data suggests that even though the O/D solenoid
does not stay energized between gears, the pressure drop is only from 470psi
to 450 psi during the shift - not enough to dis-engage the O/D.
Well I thought about what I had done and here is what turns out to be the
solution. It has to do with the clutch linkage. One of the things I did was
to remove the pedal box and weld shut the hole for the pin on which the
clutch pedal rotates. Most TR6 owners are familiar with the pedal slop which
results from the "ovalization" of this hole and the corresponding
clevis/yoke of the clutch master cyl. I then re-drilled the hole to have a
round opening to perfectly fit the new pin I installed. Along with new
clevis/yoke and new pin and rod for the slave cyl, I removed all slop from
my clutch pedal.
However... upon re-installing the pedal box, I mistakenly tightened the 9
bolts at the top of the box prior to the bolts along the firewall which hold
the brake servo and clutch master cyl to the firewall. The tip off was that
my brake lights were always on - caused by the brake pedal not returning to
its original location. I suspected that my pedal box was not as far
"forward" as it was prior to my dis-assembly. Somehow this was causing the
clutch pedal to not push as far forward as it used to into the clutch MC.
I loosened the pedal box bolts and started with the clutch MC bolts followed
by the brake servo and finally the top 9 bolts. Prior to taking it for a
drive I tested the brake lights and they now worked as before. The test
drive confirmed my theory - no more grind in O/D shifting!
... So the moral is, when replacing the pedal box, do the front bolts first
(clutch, then brake servo) followed by the top bolts. The Bentley probably
states this sequence but once I had it apart I guess I neglected to read the
"reverse steps x through y" re-assembly instructions. Oh well...
Peter Zaborski
76 TR6 (CF58310 UO)
Calgary AB Canada
|