[DeTomaso] Clutch effort reduction redo...
MikeLDrew at aol.com
MikeLDrew at aol.com
Tue Jul 29 06:00:36 EDT 2008
Hey guys,
I've let numerous people drive my Pantera over the years, and to a man
they've all said, "Nice car! But, your clutch SUCKS!"
And suck it did. The whole thing was new, a McLeod three-finger replacement
clutch with Kevlar disc from Pantera Performance Center, actuated by one of
PPC's McLeod internal hydraulic throwout bearing. It was supposed to be Da
Bomb, but it was a bomb all right....it sucked!
My car has the clutch effort reduction kit, which is supposed to introduce a
non-linear clutch response. It actually raises initial effort as you start
to depress the pedal, then as you go over-center, the effort drops down, making
it easier to hold the pedal to the floor at stoplights etc.
Anyway, my car didn't behave particularly well. You would depress the
clutch, put the car in gear, then slowly lift your foot off the floor, and lift and
lift and lift....and nothing would happen. Then right at the top of the
pedal travel, all of a sudden the clutch would grab RIGHT NOW.
The clutch engagement was exactly at the most critical point in the clutch
linkage curve, where there was the most clutch motion for a given amount of
pedal movement. The total pedal movement from fully engaged to fully disengaged
was probably no more than an inch, making for some very tricky maneuvering
when leaving from a stop. More often than not I'd have to rev the nuts off of
the car, slipping the clutch like a two-stroke dirt bike to get under way
without stalling.
I've whined about this to Dennis Quella off and on for years. Finally this
year in Las Vegas, I remembered it, and lassoed him and put him into my car
and had him operate the clutch. Without even running the engine, he said,
"This clutch SUCKS!"
Well, thanks for that...but what do I do about it?
"I have a feeling the main component of your clutch effort reduction kit was
installed backwards," he said.
Huh? I thought that piece was shaped like a simple "T"? That's what it
looks like in the parts book anyway?
http://www.panterasbywilkinson.com/webpages/catalog/ill8b.html
Nope, it turns out that this piece is irregularly shaped and has a distinct
orientation. Dennis said he'd send me a diagram, and true to his word, after
I reminded him a few weeks later, Becky e-mailed it to me.
I did what I normally do when faced with a maintenance issue--I ignored it
for weeks. Finally, today, I got a wild hair and decided to examine under my
dash, and lo and behold, the piece was installed backwards! Eureka!
Oh, wait. This whole thing is kept together with a bunch of tiny snap
rings, none of which are easily accessed. And I'm not willing to start chopping
bloody great holes in the car for a once-in-a-lifetime maintenance fix. So, I
rolled up my sleeves (well, it was hot here today, so I was wearing shorts
and a T-shirt, but I figuratively rolled up my sleeves) and went to work.
The clutch master is bolted to the pedal support bracket (plate), and the
effort reduction kit is supported on a pin opposite the one that supports the
throttle pedal. The only way to address the situation was to slide the pedal
support bracket forward a few inches, which would give the requisite access.
Doing so is a non-trivial affair, however. Sure, some of the fasteners are
simple nylock nuts on studs. Those are a breeze (except for the one that
comes to touch the clutch master reservoir; the nut can't be removed off the stud
until the plate is moved forward a bit). However, there are three fasteners
that are simple bolts, meaning one person has to be on the outside turning a
wrench, while the other person has to be upside down, under the dash, holding
another wrench.
As I was one people short, I had to go into McGyver mode to figure out how to
do both jobs at once. I couldn't get any forward motion with the brake
booster/master still attached, so I had to detach the brake lines from the master
and unbolt the booster, remove the pedal pin and remove the assembly.
Eventually I was able to get the plate broken free (you have to remove the gas pedal
also) and slid it forward a few inches.
Getting the snap rings off to turn the offending piece around wasn't easy, as
my smallest snap ring pliers were still too big. A bit of quality time at
the bench grinder sorted them out, but then one of the snap rings simply went
missing. I set it down, and it moved by itself to places unknown.
So I had to dash to the Ace Hardware to get replacements, and it turns out
there was a monthly cruise night at the Fosters Freeze next door, so I spent an
hour or more checking out hot rods and cruisers and drag cars, before
returning home to finish the job.
I got everything buttoned up, bolted up, got behind the wheel triumphantly,
depressed the pedal....
...and it wouldn't move. So, I pushed it harder, and then with a clunk it
went down about an inch, stopped, then with more pressure, continued to the
bottom of its travel.
Huh?
I cycled the clutch several times, and it was the same each time. Enormous
effort, a little movement until it hit a stop, then more movement.
I had no idea that simply flipping this piece around would so adversely
affect the clutch action. With disgust, I made my way into the house to ponder
the situation.
Then the big A-ha hit me. As one who routinely advocates RTFM, I had failed
this simple task. I remembered that the TSBs have a specification for the
clutch master cylinder rod length when the effort reduction kit is installed,
so I dug mine out and there it was--2.91 to 2.95 inches.
What was mine? I had no clue, but I suspected it was probably longer.
The only practical way to adjust the pushrod length to a given measurement is
to remove the master cylinder, which meant completely undoing everything I
had done earlier.
Hooray.
Fortunately I had learned a few lessons along the way, and round about
midnight, I had the plate out again. I disconnected the pin which let the pushrod
clevis free from the linkage, unbolted the master from the plate, then pushed
the plate back in position. My clutch line has enough flex room to let me
move it around without disconnecting it, so I was then able to get a
measurement, and determine that in fact the rod was too long. I chose to set it to the
shortest end of the spectrum, 2.91 inches, and then got everything buttoned up
again.
Now, the clutch seems to be working properly for the first time since I got
the car back from Vermont in 1995. It still doesn't impress me too much, and
there is still a hell of a squeak coming from the fingers/springs in the
pressure plate, but it does feel much better than before I started this project.
I haven't hooked up the brake lines yet, so I decided not to start the engine
to fully ops-test it yet. I quit working around 1:45 a.m.
I have to tell you that one-man
removal/installation/removal/installation/removal/installation of the brake booster, clutch master and booster/master
mounting plate is among the most miserable jobs you can do on a Pantera. I feel
like I'm now the world's foremost authority on the subject, and I really wish I
wasn't!
As always, what should have been a fairly straightforward process turned into
an epic battle. My car is the most combative Pantera on the planet, as
anybody who has ever worked on it will attest. Absolutely every obstacle that
you can imagine will present itself, often more than one time! But this time,
I think I've got it licked.
Here's a few photos taken during the course of the project....
http://members.aol.com/mikeldrew/ClutchLinkageFix.jpg
Mike
P.S. One bummer associated with this project--a neighbor stopped by for a
few minutes just as I was finishing the first install. I depressed the clutch
pedal to test it, and as I did the car started rolling backwards.
Instinctively I jammed on the brake pedal, and since the master was disconnected and
the lines were pointing straight up, two geysers of brake fluid shot high into
the air. I freaked out, but he said that all the fluid had landed on the
trash bags that I had used to line the front trunk. He mopped it up with paper
towels and chocked the wheels, and work continued.
After he left, I had gone into the house, but my Little Voice forced me to go
back in the garage and check, and I was horrified to see that brake fluid had
showered the outside of the front hood, and numerous streaks could be seen
running the full length of the hood.
AAGGGHHH!!!
I grabbed the Windex and a new cotton shop towel, and quickly scrubbed the
brake fluid off. I gave the hood several runs with Windex, then one scrubbing
with straight Simple Green, and a final Windex wipe.
I think, I THINK that I got to it before any long-term damage was done, but
it's too soon to tell. Only after the car is brought into the sunlight will
any flaws be revealed. I really hope that it's okay...thankfully the car had
a good coat of wax on it. I will need to wax the hood again for sure--but
since the car is covered with bugs from my last dusk drive around Lake
Berryessa, I'll give it a good wash and wax once I get the brakes hooked up and
bled....
**************
Get fantasy football with free live scoring. Sign up for
FanHouse Fantasy Football today.
(http://www.fanhouse.com/fantasyaffair?ncid=aolspr00050000000020)
More information about the DeTomaso
mailing list