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Discussion Starter #1
Just installed my engine and tranny with a new CenterForce I clutch in the Shelby. There seemed to be about 2-3 inches of free play in the clutch pedal so I adjusted it per the shop manual. Now the clutch pedal doesn't go to the floor when you step on the pedal. It stops about 2-3 inches from the floor. Is this normal for CenterForce clutches? It feels really weird to have the pedal stop so far from the floor. The previous clutch was the long style, so I'm wondering if there is supposed to be that amount of free play in it. The car is not finished yet so I can't do a road test. Any CenterForce clutch users out there experience this?
 

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Diaphram clutches are not supposed to have any free play. (I presume the CF 1 you have is a diaphram unit) In fact, they require a slight preload. IIRC it is 1 - 1 1/2 turns of the adjuster after the free play is taken up.

I have a clutch cable, so I am not sure how the pedal travel would work with standard linkage and a diaphram clutch.
 
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I have a Centerforce II and there is no free play. The clutch pedal goes all the way to the floor. In fact I keep hanging the floor mat on the pedal. Don't use the shop manual adjustment procedure since the Centerforce is a diaphragm style clutch rather than the old 3-finger style.
 

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While I don't have one of those, I did investigate the prospect of using one and having a lot of Chevy's with diaphragm clutches gives me a perspective on installing one. Not wanting to have the throwout bearing preloaded on the pressure plate for somewhat obvious reasons, I would: change the overcenter spring (reduce its tension), set the "free play" so as to have only the slightest separation between the throwout bearing and the pressure plate, and if the fork angle at this position was angled on the back side relative to the back of the bell housing, then to add a spacer between the fork mounting bracket and the bell housing. Note: the fork should be parallel to the back of the bell housing when properly adjusted. Note Also: the throwout bearing should not be more than 1/16" inch away from the pressure plate tines when properly adjusted. For this reason a fork pivot spacer sometimes becomes necessary.
 

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Discussion Starter #5
Yes it is a diaphram clutch with original linkage. I ran into trouble when I removed the free play from the pedal. I adjusted it so there was about a 1/2" of free play. When I pushed it down, the pedal stopped about 3 inches from the floor. So I put more free play in and then the pedal went down to about the normal height when depressed. This has me stumped. Now mind you I did all this without the engine running. Does that make a difference?
 

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Perhaps the best thing to do would be to call Centerforce. I am sure they have a tech line.

3 finger clutches require free play so the throw out bearing will not ride on the pressure plate.

Diaphram clutches and their throw out bearings are different. (atleast for Modern T-5 w/ clutch cable) They do require a preload. I was told this by a good buddy that is a Ford service manager and D&D performance transmisisons.
 
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You don't need to have the engine running. I forgot to mention that Centerforce says to remove the clutch helper spring inside the car which I did. I wouldn't think there is much if any difference between our cars with respect to set up the clutch so I guess I am stumped about the problem you are having.
 

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I called Centerforce technical assistance about the clutch adjustment in my '66 with T5Z, and they told me to use the Ford adjustment proceedure. They never said anything about preloading the clutch. When I adjust mine per the manual, I get about 1" to 1.5" of pedal freeplay, and it will got all the way to the floor. Note, I have the new-style bellhousing bolted to the Shellby 289 motor. If you are using the original bellhousing, perhaps it's a problem with the clutch arm pivot point not allowing the correct working ratio.
 

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I have a Centerforce Dual Friction clutch in my 1967. Sounds like you had the clutch adjusted about right before you started your adjustments. The spring on my clutch linkage is just marginally strong enough. Sometime I have to give the pedal a slight nudge with my toe for the pedal to fully rise; this is after the clutch is fully engaged. I also have problems with my new floor mat shifting up enough to catch the pedal and hold it fully down. The 11" clutch controls very easily the 400 HP 351W (aluminum heads, etc.) engine.
 

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I don't agree with the clutch preload.... If you do that, the throwout bearing will spin constantly, fail early, plus any pressure on the pressure plate fingers will reduce the clamping force.
I've installed several C.F. clutches, never saw anything about preload...
 

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I did fail to mention the my clutch is the King Cobra clutch and not a CF, that is why I deferred to calling CF.

I did check some old information that I had and for the King Cobra, a preload of 7 lb is specified. Per D&D, 1/2 to 3/4 turn on a clutch cable adjustment nut is about right.

Here is an excerpt out of a Ford Service Bulletin "

Clutch Pedal - Vibration Heard or Felt Article No. 00-24-1 11/27/00

VIBRATION HEARD AND/OR FELT AT CLUTCH PEDAL FORD: 1990-2001 MUSTANG ISSUE
THIS VIBRATION NOISE WILL EMIT FROM EITHER THE CLUTCH PEDAL AREA OR FROM WHAT APPEARS TO BE BEHIND THE DASH OR BOTH.

Some vehicles may exhibit a vibration that may be heard or felt at the clutch pedal between idle and 2300 rpm, and goes away when depressing the clutch at least 25 mm (1"). This may be caused by the lack of reserve, quadrant binding, improper clutch cable routing, *****lack of preload on the release lever*****, improper or failed release bearing, improper pressure plate-to-flywheel bolt torque, or out-of-parallel finger height on pressure plate. ACTION Check, inspect and correct above items as described. Refer to the following Service Procedure for details.

Here is a second opinion from an esteemed VMFer http://forums.vintage-mustang.com/forums/showthreaded.php?Cat=1&Board=forum&Number=171808&page=&view=&sb=&o=

Best advice is to check with the clutch manufacturer and follow their instructions.
 

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I have a CF Dual Friction diaphram clutch in the Fastback. I'm using the original 66 clutch linkage, Z-bar, clutch fork, throwout bearing, and 157/160 tooth aluminum bellhousing. I can adjust the clutch to produce a range of freeplay from 0 to over 2". In all cases, the pedal will still go all the way to the floor. I ended up adjusting it to have about 1" free play. I run the idle up to about 2000/2500 rpms in neutral and slowly depress the pedal until I feel the throwout bearing "slightly vibrate" indicating that it has contacted the pressure plate. This is harder to detect at a dead idle or engine off. This adjustment produced a clutch engagement/disengagement at about half pedal. In street driving, this has been very comfortable with good clutch "feel". This weekend, I'm going to try a few timed runs at a dragstrip. The one remaining question is whether the CF pressure plate generates enough force at high rpms to overcome the "over-the-center" heavy spring under the dash and return the clutch pedal back up. These clutches increase clamping pressure in proportion to rpms, so while the pedal returns OK in normal driving, it may not at 6000 rpm shifts. Some recommend removing the over-the-center spring, but I hope that I don't have to.
 
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