Clutch - soft and weak

[FMJ_Blazer]

Have a 1971 blazer...Just installed a rebuilt SM365 mated to a 350. I used centerforce II clutch/pressure plate and throwout bearing. When I press the clutch pedal, I feel very little resistance to the point it doesn't feel like it is engaging with pressure plate. Any ideas before I pull the tranny back? Does anyone know if I should have the short or long throw out bearing? Any help would be appreciated.

[LockDoc]

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Have you re-adjusted your clutch linkage? If I remember correctly you should have 3/4-1" of free travel at the pedal before the throwout bearing makes contact with the pressure plate. What throwout bearing was in it before?

LockDoc

[FMJ_Blazer]

There is no real difference in how the clutch feels once you press the pedal - free travel or not. You feel no "real" pressure at all. I can't remember what bearing I had in originally. It has been a while since I pulled out originally. I replaced with all new center force parts including the TO bearing - I believe it is the short version.
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[Lee H]

Light pedal feel is a characteristic of center force. Not like the old school muscle building clutches of old.

[Wrenchbender Ret]

I take it you still have the pilot tool in the clutch disc if you are disengauging the clutch with out the trans in. Other wise the disc will be out of possition. Some trucks with a heavy duty clutch have a overcenter spring on the pedal arm under the dash. This helps push in on the clutch. If it has this & you put a clutch with a lighter spring it will have a real odd feel & may not return. Use the TO brg that comes with the kit. The long TO brg. is for the old style clutches. I like a soft clutch but always thought performance clutches are real hard to push in.

[FMJ_Blazer]

I have the tranny in and the pilot is not in. I am breaking in the engine today and will try to put in gear and see what happens. My jeep with center force doesn't feel as light as this one does and just felt something must be wrong with out really testing it. I used the TO that I ordered and believe it is the shorter version. Crossing my fingers and wrenches for later today...will keep you updated. Thanks evenings help/input. If there is more - bring it on.
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[FMJ_Blazer]

I chicken'd out...i have not bled my brakes out yet and di not want to attempt putting into gear without brakes. Attempted to bleed brakes and the bled valve snapped off while trying to loose! I guess that is how it goes. I have a few questions after attempting to break in the new engine:

1) Temp running at 194-212 depending on where you shoot with infrared - hottest is on the heads facing the engine. does this feel right for break in?

2) I noticed a little smoke of some sorts coming from left inside of radiator - brand new radiator - just seemed weird. Any thoughts?

3) On this clutch thing - I removed bell hosing pan to look at fork, TO, and clutch. When you press clutch pedal it engages TO against pressure plate- barely. It is such that the bearing has about 1-1.5" of slide before hitting pressure plate springs and then it just snugs up to them and doesn't seem like it is doing anything. Any different thoughts now?

Will load pics as well. thanks for everyone's help

[dan76]

Is the correct side of the clutch disc facing the pressure plate?

[FMJ_Blazer]

I am pretty sure...any suggestions on how to make sure when it is installed - viewing from the bottom? I was very careful (i think ) about putting the clutch on the right way so pad was facing the pressure plate

[FMJ_Blazer]

Trying to attach general pic

[Wrenchbender Ret]

Have you adjusted the clutch linkage. The pedal should go down about 1/2 to 1 in and then the brg contacts the clutch.

[FMJ_Blazer]

Ok...this might be a dumb thing, but I was looking at a LMC catalog and noticed they show a clutch pilot bushing - I don't recall installing one when I put the TO and fork in. Could that be my problem? Does this advance the TO bearing further towards the pressure plate?

[Wrenchbender Ret]

The pilot bushing presses in the end of the crankshaft. The end of the trans. input shaft goes in it when the trans is installed. This keeps the shaft centered. Unless you changed from an automatic the pilot bush was in there, but is more then likely worn out. It must be in good condition or it can cause iratic clutch operation & damage to the trans. & or the clutch. It would not cause the problem you are discribing here though. There should have been a new one in the clutch kit.

[LockDoc]

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It sounds to me like you need the long TO bearing unless you have a lot of adjustment in the clutch linkage rod at the end of the clutch arm.

LockDoc

[FMJ_Blazer]

Nope - not enough linkage left. I will contact centerforce and see which one they recommend. Thanks for the input/advice. Really appreciate it.
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[LockDoc]

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No problem. Let us know what you come up with.

Be sure and check that pilot bushing that Wrenchbender was talking about in his last post. Very important as he mentioned...

LockDoc

[FMJ_Blazer]

Locdoc/Wrencher....can one of you explain the pilot bushing a little more detail for me. Sorry for ignorance, but need to know where it goes and how. Pictures are helpful.

BTW - I talked to Centerforce and they said that I should look at pivot ball extension and/or longer TO (N1466 model).

I am trying to cross off the list of possibiliies including bell housing. I took it off before sending tranny in for rebuild so I know it is the right housing and wouldn't be modifying my length to clutch/flywheel.

traveling but will check forum as often as i can.

[Wrenchbender Ret]

There are 2 kinds of diaphram clutches used by GM. The older style has the fingers parallel with the plate & are about half way inside the assembly. This one uses the long TO brg. The later one has the fingers extended outward & are about even with the edge of the cover. This is commonly called a beehive clutch. It takes the short TO brg. The short brg has the fork groove close to the back of the brg. The long brg has the groove about 1/2 in. behind the brg. Either will work as long as the corresponding TO brg. is used.
The pilot bush. is in the end of the crank. You cannot hardly see it unless the clutch is out. It is bronze in color. They can be ornery to remove. You are supposed to be able to pull it with a slide hammer puller but that seldom works. Some guys pack the recess with grease or TP or other cococtions & hammer the pilot tool in to remove it hydraulically. I take an air chizel & wack it up. Clean the recess good & tap the new one in with a drift being careful not to mushroom the opening.

[FMJ_Blazer]

Got it now. Thanks. I bought a blueprint engine...so nothing to remove...only to tap in. Pulling tranny this weekend to install pilot, recheck clucth and pressure plate, install adjustable pivot ball and potentially a longer TO. I hope this does it. Will follow up with the results after the weekend. Thanks for the help. Just ordered front and rear bumbers from tactical armor group in Georgia....The father/son project is getting close.