I have an experience to share with the list. I've just completed the
installation of a new Pinion Seal in my TR4A IRS Differential. Thanks to
everyone who supplied the correct seal and Speedi-Sleeve part numbers.
The Differential unit mounts via 4 spots and is held somewhat rigid to the
frame. The front mounting bracket is held to the Differential case with 4
bolts. While it's not absolutely necessary to remove the bracket from the
Differential; doing so makes the whole job much easier and allows for better
cleaning of the whole assembly when on the bench. The 4 bolts use thin star
type lock washers instead of the more traditional and thicker spring style.
Mine were original and just fell apart when I disassembled the bracket from
the case. The word thin is a hint to what's coming.
When re-assembling the unit I used new spring style lock washers. Let me tell
you that's a mistake as the difference in thickness of the washers is critical
to later necessary clearances between these bolt heads and the 4 bolts / nuts
that connect the driveshaft flange to the Differential Pinion Flange.
Once the Differential was re-installed into the car and I attempted to bolt up
the driveshaft the head of the bracket mounting bolts interfered with the nut
on the bolts for the Pinion Flange attachment. It was caused by the difference
in thickness of the washers that I replaced. I fixed that problem by using a
thin washer under the Pinion Flange bolts rather than remove the whole
Differential Assembly again.
Lesson learned, even if it's not obvious, replace old parts with the same
style new parts, there just may be a reason why the engineers did what they
did. That was certainly the case in this example.
With all of the work I've done over the years it's still possible to learn a
lesson. This one will hopefully be remembered by me! It's amazing that so
little clearance was originally engineered into that system. Or was it a
mistake that was fixed by using a thin star type washer at the factory? I'll
never know but I suspect that someone passed by that turn in the trail before
me.
Jerry Van Vlack
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