>Date: Mon, 28 Jul 1997 09:28:32 -0400
>From: Ken Streeter <streeter@sanders.com>
>Subject: Clutch pedal / pushrod hole elongation [was Re: Clutch engagement
problems]
>How do people typically fix this properly? The
>holes in both the pushrod and the clutch pedal
>have been "elongated" on my cars.
>
>There don't appear to be any bushings in the TR6
>clutch pedal or the pushrod that can be readily
>replaced.
>
>Suggestions?
>
>- --ken
>'70 & '74 TR6 Daily Drivers
I had similar problems on my TR-8 and wire welded a couple washers on both
outer sides of the "fork" portion. I then filled in the worn portions of
the original part with welding wire (using a Century wire welder). I
drilled the hole back out to the proper size and used a slightly longer pin
to account for the extra width from the welded washers. I now have more
than double the original material to carry the load and no free play. There
was no wear on the hole in the clutch pedal, it is much thicker than the
combined thickness of both sides of the fork. However, if it was worn it
would be easy to repair with the same method of adding metal with the
welder, then redrilling. Since it is already thick it wouldn't be necessary
to add washers. I don't know of any easy way to improve the original
design. A little lubrication might help, but the original design lasted
over 100,000 miles. If my repair lasts that long I'll be happy.
If you don't have a welder available it may be cheaper to just buy new
parts. They are readily available for the TR-8, but I don't know about the
other models. Yes, they will eventually elongate just like the original,
but one thing to keep in mind is that these cars were not designed for the
kind of miles and years they are now reaching. Current design practice for
most of the Big Three today is to design powertrains and most other parts
for 10 years/150,000 miles. There are active campaigns to take design
margins out of parts that will last longer than that if it will save money
(aka "value" engineering). As always, mistakes can be made and parts that
never broke mysteriously start breaking -- that $0.05/part savings suddenly
turns into a multi-million dollar warranty problem. All part of the pursuit
of making the "best" product for the "least" money. Somehow I suspect that
the design life targets for our cars (if there were any) were significantly
lower than 10yrs/150,000 miles, and worn clutch linkages in 20 year old cars
are really miracles of engineering :-) We're probably also fortunate that
the design tools weren't as good back then to let them take margin out of
the design as readily as we do it today (sometimes successfully).
Ben Zwissler, zwissler@mail.hsonline.net
Columbus, Indiana
1980 TR-8
1966 TR-4A IRS OD
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