Hot Rods Clutch pressure plate issues

Wanderlust - That was my thoughts on the pilot bushing/bearing as well.
Good tips on assembly, thanks! My alignment tool is specific to this combo, so it's the most accureate I can get.
Fingers crossed, I'm heading out to the garage now!

 

Ok, I just put everything back together, and it is still stiff as hell and pops/oil-cans.
I know, the input shaft isn't in place so the throw out bearing isn't "exactly" centered. I do have an alignment tool inserted. I'm trying my best to make sure the throw out bearing is centered and that the clutch fork is centered and is snapped into the ball fulcrum.
I made two videos. Since I don't know how to post a video on this forum, I posted them to youtube.
(They published as "shorts" because they are both under a minute)
Anyway, take a look and see what you think.
Thanks
https://www.youtube.com/shorts/KEtWk42YrKk
https://www.youtube.com/shorts/n_6_V2UODuQ

 

My latest thoughts after watching the videos...and reading some missed replies. Are we over thinking this as a problem?

The plastic alignment tool that came with the kit is both a blessing and a curse. If it doesn't fit snuggly, the clutch will be out, off of center ever so slightly. I would double check that. Usually it sags slightly from the weight and the tool needing to be firmly pushed lifting it as it's bottomed out as the pressure plate is tightened down evenly. But it could be left to right as well, ever so slightly.

The amount the clutch lifts to disengage when the peddle is pushed...

I'm just saying...that isn't very much movement.

Thinking about the measured action of pushing in the clutch peddle...you'd expect more separation.

I'm not sure but I'm still betting money it's a clutch alignment issue. Pressure is being applied but unevenly in lifting the clutch.
Prices subject to change since HOTROD June 1989 gave that up.

I have a new clutch package in this combo. I'm almost certain that what your experiencing is mostly normal. Mostly. I've also almost convinced myself to cut back the plastic and make a video of it's fork in action. Almost. I won't... but I did think about it briefly.
That said, if that disc is out every so slightly, it'll most likely lift, and if not fully lifted, maybe slip and slide some until it wears funny, or self centers over time to some extent by or through pedal action. Or so I would think? Especially if you get those fingers bending, maybe that's what's happening?

 

Did you check your clutch fork and throw out bearing on the bell housing bolted to the gearbox making sure it is all centred and works properly on the input shaft. When everything is bolted back together on the engine, is there free play in the clutch fork, eliminating too long a Tob. Just eliminate one step at a time

 

This may sound Dumb as Hell but I'm going to put it out there anyway. Did your T.H.B. come assembled on the Carrier? I don't remember any T.H.B's with a ridge on the Face side contacting the Clutch fingers. To me this just visibly don't look right. Seems like the bearing face should be FLAT all the way across. I'm not sure I have a used one to go look at. Someone do it for me and post up a photo.

 

Is it possible the Bearing is on the carrier backwards?

 

Dude, I'm pretty sure your T.H.B. is wrong. I just slid this off my 4 Speed and it mounts to a Diaphram style P.P. Flat face all the way across as I thought. I think that Rib Fucked you up!

 

I agree with @Pist-n-Broke , I had mentioned the radius faced throw out bearing in an earlier post, it’s used with flat finger diaphragms. Go to your local auto parts store and look for a TOB with a gentle radius on the face.

 

NoelC- I agree with the plastic alignment tool sometimes not working as well as an input shaft. However, I have had the transmission installed in all of my previous attempts with the same symptoms. I was able to reenact the symptoms by pulling on the clutch fork with the engine on the stand in the videos.
The clutch gap is an interesting idea. Maybe I will use my other bell housing that already has a window cut into it and see if I can measure the distance.
Thank you for your thoughts and the information. I'll keep that in mind as I try to solve this problem.

Beater40- thanks for your ideas. Yes, I've had the transmission installed to the bell housing and had the engine transmission combo installed and removed in my truck several times, reworking the clutch linkage and trying to solve this problem. I did not bolt the transmission to the bell housing for this video so that I could show the action of it all.
Yes, there is free play in the clutch fork and I believe that I have the tallest throw out bearing available for Chevrolet with this flat pressure plate. All good thoughts

Pist-n-broke- thank you! At least I have hope that it's a simple throw out bearing mix up. This throw out bearing came with the pressure plate along with a pilot bushing. Like others have said in the past, whoever assembled that package at the factory could have easily put the wrong throw out bearing in the Box.
I'll do some searches on RockAuto to find a year and model that came with a tall flat face throw out bearing and call my local auto store. Hopefully I can pick that up today and see if that solves my problem!

Fordors- I remember you mentioning the face surface of the throwout bearing earlier in this thread. That was the reason I took the picture of it when I took pictures of all of the parts. Thank you for mentioning that as a possibility.

Does anyone know the year span and possibly model of cars that you would find a flat faced tall throughout bearing? I'm assuming most any inline six powered chevy passenger car from the 60s to the 80s?
Thanks!
I'll do a search on RockAuto right now and come back with my findings.
Thanks for this recent observation! Let's hope it works!

 

Okay, I just went to RockAuto and looked up Chevrolets with a 250 inline. 1972 Nova, 1970 Chevelle and a 1965 Bel Air. All of them showed the exact same throughout bearings (which they call a clutch release bearing)
Here is two examples of the ones I found. They look exactly like what you guys are describing and they appear to be tall as well.





I'll do some calling right now and find out who has one

 

I know that they make different ones that have different lengths, but I think they also make an adjustable one as well. The thing I would look at is when the clutch and housing are in place, is the clutch fork inside the housing angled back toward the transmission. Then when you get it to pop and release........is it still slightly back or is it now angled forward? What you want is for it to be slightly angled forward. During this movement, does the clutch fork make contact with the housing or the pressure plate? By that, I mean the area on the fork thats between the throwout bearing and the pivot.

If this does not look correct, you may need a shorter throwout bearing. There are 3 lengths.....or the pivot point needs to be changed somewhat.

I'd say your problem is not the clutch or the pilot bearing, but the relationship between the fork/pivot/bearing. One or more of those is incorrect.

Yes the adjustable fork pivot "might" solve the problem. I would just insure that the range of motion allows clearance and that you are starting "behind" the center of the pivot point where the to bearing and fork contact the clutch.

 

I can't understand the change? Why bolting it down with a clutch in place causes the fingers to flatten? That to me seems wrong.
Wrong as in somethings not right?


As for the protrusion on the surface of the clutch release bearing, how does it compare to the hole in the fingers? If it fits the hole, I don't see a problem.




Could be that's just a camera angle thing?
Ok...I done some digging. Dusty digging. If memory serves, this was out of a early 70's Nova, 250 6 cylinder 3 speed floor shift car.
The box under the housing holds the parts the 4 speed trans clutch package came in.

My parts look almost like your parts.

Clutch release bearing is different and flat faced, radiused outer face.



Also in hopes it's of benefit, an image with a part number, depth, and oddness.
My clutch fork has a broken spring finger it seems. I'll have to remember that and keep an eye out for another.





The clutch pressure plate was of a similar design to yours and required to much effort to drag out for pictures. But if you think they'd help you out let me know. I just might anyways, It will show the wear on the end of the fingers from the action of the clutch release bearing. It being a used part, my memory, about 0.093 - 0.125".

In recapping, correct way to install a clutch disc - Google Search

 

That’s normal. Think about what direction pressure plate travels and which way fingers go when a clutch releases?

 

^^^^. What Johnny says, the PP , in effect, is pushed into its housing, which is kinda like depressing the peddle.

 

Ekimneirbo- I think the answer to your first question about the clutch fork can be answered if you watch the videos that I made. I shared two YouTube links. I agree with you that it definitely has something to do with the fork the pivot or the throwout bearing. I just picked up the recommended throwout bearing and I will be trying that tonight.

NoelC- when the pressure plate gets bolted down to the flywheel, the friction ring is being pressed against the clutch disc. The diaphragm springs are pivoting on outer fulcrum rings. As the diaphragm springs get pushed in, or towards the engine, that leverages against the fulcrum ring and lifts the friction ring away from the clutch disc, or towards the transmission. It's hard to explain without a video but there are videos that explain the process. Trust me, I am more educated on how everything works now then I was a month or two ago! I had no idea I was going to be watching so many videos for research, lol!
The ridge on the surface of the throwout bearing did not rest inside the inner diameter of the diaphragm springs. It actually rested on top of those springs. And you are correct, the camera angle made the clutch disc look as if it was misaligned however, I have an alignment tool installed and once the pressure plate was torqued to the flywheel, the alignment tool slid in and out very easily.
Thank you for digging into your parts for me! That throw out bearing looks just like the one I picked up today. I will be starting with that first.

Johnny Gee and Budget36- thank you for the explanations. It is kind of hard to visualize it until you've done it six times in a row like I have! Haha!

So, I just got back from Napa and they had the part I needed! This thing looks like a beauty and I'm hoping I will have some good results with this tonight. Wish me luck!

 

I guess it is what it is... but it's not what I recall those fingers doing?
Flattening down is normal??? I'll be damned. I almost want to get dusty again.
Call me confused because it's not what I recall happening, yet I haven't touch anything related in years to solidly confirm or deny.
As it is, I have the parts. If it bothers me long enough I can always come back with a "you guys were right". But for now I'll just give it to ya.
The Monster's problem... sounds like the release bearing's going to do it. Good Luck!

 

@The_Monster all things being as equal to real life. Rather than using install tool for disc as a guide, install trans instead. Skim the snout of trans bearing retainer with a very thin amount of grease as well as the ball socket of fork and give it a try. Also there should be a groove inside throw out bearing. Add grease into it. Note, a grease that does not go runny or liquify.

 

Most of this has been covered already . . . but what the heck.

When the PP is not installed the spring(s) push the plate to it's full travel, allowing the fingers (or diaphragm) to move to a raised position. With the PP bolted in place to the flywheel, the thickness of the clutch disk restricts the full travel of the PP and the fingers will move to a more flattened position.

One of your earlier pics of the P.P. kind of caught my eye. The uneven wear pattern on the fingers just seems strange to me. Especially on a new pressure plate that hasn't seen any real road use yet.



This last part likely doesn't apply since you stated that the raised rib on the I.D. of T.O. bearing did NOT fit down into the opening of the diaphragm. But I'm just putting this out there anyways.

Consider also the diameter of the opening in the center of the diaphragm spring. This diameter will change slightly as the PP is cycled between fully applied and fully disengaged. With the pedal depressed to release the clutch the diameter of that opening will be smaller. The TO bearing you originally installed has that raised bead around the I.D. of the contact surface. I can imagine a situation when the pedal is depressed where the very tips of the fingers on the diaphragm (or at least some of them) are catching on the outer edge of that raised bead. Pressing the pedal further eventually forces the fingers over that lip and would likely give you the "oil canning" effect that you're feeling.

 

diaphram clutches are very hard to press, change to a 3 finger style pressure plate and it'll be much easier to depress. Bottom line GM pressure plates No Good, Ford 3 finger pressure plates Good.

 

NoelC- yea man, go get dusty this weekend and break out the tools. I had to wrap my head around it at first as well because you would think it would do the exact opposite until you realize that each one of those diaphragm springs is a lever. The area of the diaphragm springs that we see are the longest part of the lever. At the other end of the lever the spring is hooked underneath the friction ring. There is a fulcomb ring that goes around the outer diameter that the diaphragm rings pivot on. So as you push in on the diaphragm springs, the springs pivot on the fulcrum and the other end of the diaphragm spring lifts out the friction ring.
You can even look up components of a pressure plate or an exploded view of a pressure plate and there are some really great illustrations out there.

Johnny Gee- I definitely will mount the transmission to the bellhousing this time for a true alignment when I test it with the new throw out bearing. Good tips on the greasing. I was surprised to see some thick black grease on the inner groove from the factory. You can kind of see it in the pictures. I'll add some more on the inner diameter

ClayMart- the picture of the pressure plate is a little deceiving. Since this motor has not ran yet with this clutch on it, those are not a wear pattern. Those were grease marks from the throwout bearing and I had wiped some of the diaphragm springs off because I thought they were wear marks as well. Turns out it was just grease. That's why it looks strange that only some have marks and others don't. Good catch though!
Your theory on the throw out bearing raised edge and the inner diameter of the diaphragm springs becoming larger as the clutch fork is depressed is very interesting! I'm going to check that out tonight to see if that is a possibility. That's a very interesting idea. I'll let you know what I find out!

John Lee Williamson- I'll give you that there's the possibility that a three finger pressure plate maybe easier to press. However, GM sold many thousands of vehicles with this set up. I feel that if they were no good, GM would have changed the design somewhere along the decades of using them.
I think I'm going to stick with what originally came with this engine/transmission combination, and if for some reason I can't make any progress, I may consider your suggestion.

 

Well....shit....
I would love to be putting this engine/trans back in my truck this weekend, but that's not the case.
The new throw out bearing didn't change the oil canning. Still hard as hell to push and still pops in/out.

Lets cancel out what I know is OK.

1-Flywheel is just a solid disc, its fine.
2-The bellhousing looks like all the others, its most likely fine.
3-I've tried two throw out bearings, it's not that.
4-The ball on the bell housing I feel just adjusts slop between the pressure plate and the throw out bearing. I don't think that's the issue because I have a stock ball installed, threaded all the way in at the stock depth.
5-The clutch fork is stock, as far as I can tell. Even if it's not, it can only be so long from the ball to the throw out bearing. From the ball to the shift linkage could vary in lengths, but that will just give more/less leverage. I don't think the fork would give an oil can effect.
6-Could the clutch disc be too thick?????? Even so, why is it SOOO stiff to move the clutch fork BEFORE it oil cans??

Here's my hunch: That throw out bearing came with that pressure plate kit. Maybe the throw out bearing wasn't wrong for THAT pressure plate. BUT, that whole kit is wrong for MY application. Maybe now I have the correct throw out bearing, but I also need the correct pressure plate!

I think the pressure plate kit I ordered was incorrect.

Here's a video I just posted. I have the new throw out bearing AND the trans installed, so the input shaft and clutch disc are aligned.

https://www.youtube.com/shorts/3I6H9s3rTM8

What are your thoughts?

 

I have read this whole thread and probably missed or just don't remember but are you sure Disc is in the right way?

 

First off, I have never seen anyone work a Clutch Fork by hand. Seeing it makes me wonder if you have any actual problem at all. The P.P. works on a to Center and Over center system. It's the swing pedals and helper spring that determines how smooth the system works. You can't have the same amount of Spring pressure happening at a Stop Light as you do fully engaged. It makes perfect sense to me what I'm seeing happen, except the fact you can actually do that. The mechanics of the P.P. is exactly the same as the Fork and Ball. They override each other at opposite ends of the movement. I think I'd finish installing things and hook up the pedal and see where it goes from there.

 

Seb fontana- Yes, I always go by this rule: Grab the clutch disc by the springs. You can only grab the springs on one side. Now, push the disc against the flywheel and insert the alignment tool.

 

Pist-n-broke- I put a long breaker bar on the clutch fork too, and it still oil cans. The pedal oil cans, and linkage oil cans. I just wanted to show that the oil canning is still happening while bypassing all the linkage and pedals. I've pulled clutch forks before and even fully depressed a pressure plate by downward pressure on a bench before. This thing is a monster!
What's interesting is, I went to O'Reilys Auto looked up a clutch kit for a 1972 Nova with a 250 and it comes with a different version of a throw out bearing that also has a bead around it. The pressure plate looks identical.

Really strange...

 

Pist-n-broke- What I meant to say was, I have already had this in/out of the truck several times. I reworked the linkage, the Z bar and pedal, thinking it was a linkage binding problem. By showing the clutch fork producing the oil can by itself shows the oil canning is inside the bellhousing somewhere

 

Well... As porky pig would say, son of a b b , son of a b b, son of a b b gun.

 

At this point I might try a set up from a different source, not trying to be harsh , but the LUC kit seemed to me to be bottom of the food chain.

 

It's going to be very interesting when you finally find the problem. Personally, I'm baffled. Would you suppose it's just a defectively built P.P?

 

And I still agree with you, it's in the Clutch itself.