Fieros with standard transmissions, particularly early models,
have clutch problems because: the clutch cross-shaft (fork) bushings are
You know something is wrong with your clutch when you experience
one or more of the following symptoms:
- clutch pedal gets hard to push
- transmission begins to grind going into reverse
- odd clutch release points (point where the car begins
to move varies, sometimes at the top of the pedal
travel, sometimes at the bottom, other times in the
- clutch fails to engage when cold (you push in the clutch,
select a gear, let out the clutch and nothing happens.
Several seconds or even minutes later, it engages and you
- transmission will not go into gear while engine running.
(If you turn off the engine, engage 1st gear, you can then
drive off. Gear changes are made on the synchros of the
transmission, not the clutch release.)
- clutch slips (Doesn't drive at all! Even a new clutch may
not last 60 seconds while slipping!)
- release bearing rattles. (Release bearing may normally
make a slight noise when pedal depressed but stop when
- sometimes the release bearing presses against the pressure
plate at all times. (The bearing is not designed to run
constantly. When it fails, it will burn a hole clear thru
the pressure plate spring fingers. You will not be able to
disengage the clutch if that happens.)
When GM engineers specified the clutch cross-shaft bushing
clearances, they evidently were not cognizant of some or all of
the following points:
- GM engineers assume that both bushing holes in the
bellhousing are drilled in a perfectly straight line. In
practice, perfection is seldom possible. If one or both
holes, are off even a few millionths of an inch, the shaft
may bind and the clutch slips.
- Temperature distortion. Metal expands and contracts with
temperature changes. The bellhousing distorts slightly when
subjected to temperature extremes. When the shaft binds, the
- Bolting the bellhousing to the engine can cause distortion.
- The bellhousing is a hostile environment, internal parts are
not bathed in oil, as inside a transmission. Dirt, from a
normal wearing clutch disc, gets in the bushings. You
guessed it--the shaft binds and the clutch slips.
- There are no dust seals inside the bellhousing. The
designers appeared unaware of clutch dust. There is however,
an external dust seal on the outer bushing. This is to
prevent dust, engine compartment dust, from entering. In
reality, it just makes it harder to grease the outer bushing.
- The bushings must be pressed in. This causes a slight
compression of the bushing, causing the shaft to bind and
the clutch to slip.
- Production tolerances. When GM orders a part, they specify
its design limits. They do not ask the supplier of what
tolerances he is capable. GM demands a perfect part and that
is impossible. Normal production variances cause, on
occasion, a tight fit and a slipping clutch. This could
easily be avoided if GM were to specify tolerances based on
the real world.
- If you have a tight fit and clutch dust, you must have a
grease fitting for each bushing. There are none.
The entire clutch system appears to be a one-off show car design,
never intended for production, because:
- there is no adjustment anywhere for pedal free play
- $200 worth of hydraulic parts are used when a $25
clutch cable would have been much more sensible.
Remember that the Fiero project was a design "exercise," viewed
as an interesting project or "busy work" by the designers. When
the project WAS scheduled for production, it was canceled 3
times. When the 4th go-ahead was given, the designers weren't
about to risk embarrassment and another termination of the
project by pointing out "glossed-over" designs. These people are
all gone now, so their strategy worked for them...sort-of...in
the short run...but may the "Ghost of Fieros Past" haunt them!
Back to tight bushings: When the clutch release cross-shaft
binds because of tight bushings, heat, mis-alignment, clutch
dust, etc., the clutch lever and the clutch pedal are both
overloaded. The lever flexes and cracks, the pedal bends--and
eventually, the clutch slips!
It should be obvious by now that just REPLACING THE CLUTCH
doesn't solve the problem. You must ALSO add clearance to both
bushings on the clutch release cross-shaft and, possibly, to the
clutch-release bearing shaft (the input shaft retainer.)
The Temporary Fix!
Early clutch failure can sometimes be postponed. This is how to
get by without replacing the clutch, if you're lucky!
You must lubricate the outer bushing (now and often). You should
squirt oil between the clutch lever and the bushing dust seal.
The oil should work its way in. If it doesn't, remove the lever,
pry out the seal and squirt in the oil. Skip this step and you
can go right to the $800 clutch job.
Why is this a temporary cure? Because you can't lube the inner
bushing without removing the transaxle!
The Ultimate Fix!
When your luck runs out, you will need a new clutch--and you must
add clearance in the proper places or the same problem will occur
The process of adding more clearance will extend a normal clutch
job about a half hour. A mechanic familiar with the procedure
will be able to do it much more quickly, probably about 10
minutes extra time.
You should talk directly with the mechanic, not just to the
service writer, and explain what is needed. Since the procedure
is a little out of the ordinary, a $10 tip before he starts and
another when the job is done (and he can prove there is
sufficient clearance) may be in order. Insist on seeing the
final clearance check (while everything is still apart).
Fix It Right The First Time - Add Clearance For The Permanent Cure
- Remove the release bearing
- Rotate the clutch lever (outside the transaxle) back and
forth while you slide the clutch-release cross-shaft out.
- Polish the clutch-release cross-shaft with a 1" by 12" strip
of emery cloth at the points where it fits into the bushings.
Wrap a piece of stationary around the shaft (Cut out the
guide on the back of this page) and try to slide the shaft
back into the bushings. If it won't fit, continue polishing
until it does! Be sure it slides into both bushings with the
paper before final assembly. That will give about .006"
clearance at both bushings!
- Clean the bellhousing to remove all clutch dust. Grease both
bushings with the best grease available.
- Check clearance on the input shaft retainer (the clutch
release bearing slides back and forth on this part.) This
should also be about .006" clearance (use the same "paper"
trick to determine it.) If it needs more clearance, either
hone out the clutch release bearing (with a brake cylinder
hone) or use emery cloth on the input shaft retainer. When
you install the release bearing, be sure to pack the release
bearing groove (where it slides on the shaft) with high-temp
grease, prior to assembly.)
Remember to remove the paper before assembly!
You should still squirt oil on the outer bushing every 3-6
months. With the larger clearances and lubrication it will take
a lot longer for the same clutch problem to occur again, if ever.
From: Fiero Secrets, the newsletter of Matt Gruber's Worldwide Fiero Club (now defunct)
Online Service Guide Main Page