[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....






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