Need suggestions for non-working clutch (1 Viewer)

[Toysx2]

]Hi all![/SIZE]

I am running a SB 350 engine connected to an SM465 Chevy transmission which in turn is connected the old style Toyota transfer case through an Advance Adapters adapter. These are in a 1968 FJ40. I recently pulled the transmission and transfer case to replace a leaking front seal on the transmission and the front seal on the transfer case. I replaced the clutch fork(cast iron with cast iron), clutch fork pivot ball, throwout bearing retainer, clutch(12” LUK with 12”LUK), and throwout bearing. When I got it all back together, the transmission would not shift. When the pedal is depressed the disk is still held tight between the pressure plate and the flywheel. I thought that I was not getting enough throw from the slave cylinder—slave piston was not traveling the full length of the cylinder bore. Now it had been shifting ok before I pulled the transmission. I adjusted the rods on the master and on the slave and bled the system with no improvement. I then read on the main forum to use a brake master cylinder to get more volume of fluid. I tried that and the piston is now coming half of its length out of the cylinder. The clutch disk still appears to be tight. So I am looking for suggestions on what to try next. I am ready to pull everything back out—except that I am not sure what to look for when I get it apart. Maybe its time to spring for Centerforce type of clutch? Thanks!

 

[inkpot]

]Hi all![/SIZE]

I am running a SB 350 engine connected to an SM465 Chevy transmission which in turn is connected the old style Toyota transfer case through an Advance Adapters adapter. These are in a 1968 FJ40. I recently pulled the transmission and transfer case to replace a leaking front seal on the transmission and the front seal on the transfer case. I replaced the clutch fork(cast iron with cast iron), clutch fork pivot ball, throwout bearing retainer, clutch(12” LUK with 12”LUK), and throwout bearing. When I got it all back together, the transmission would not shift. When the pedal is depressed the disk is still held tight between the pressure plate and the flywheel. I thought that I was not getting enough throw from the slave cylinder—slave piston was not traveling the full length of the cylinder bore. Now it had been shifting ok before I pulled the transmission. I adjusted the rods on the master and on the slave and bled the system with no improvement. I then read on the main forum to use a brake master cylinder to get more volume of fluid. I tried that and the piston is now coming half of its length out of the cylinder. The clutch disk still appears to be tight. So I am looking for suggestions on what to try next. I am ready to pull everything back out—except that I am not sure what to look for when I get it apart. Maybe its time to spring for Centerforce type of clutch? Thanks!

Howdy! Did you replace the throwout bearing with the same model? There are long ones and short ones. Also, it is possible to put the throwout bearing on backwards. John

 

[hj60]

It's also possible to put the clutch disk in backwards.
Ask me how I know that.
I spent 2 hours checking everything I did. Then, I pulled the tranny back out and sure as s***, the disk was in backwards.
Your symptoms match mine exactly.
LUK marks their disks to avoid this. I was in a hurry. I just slapped it on there.
It's a mistake I will NOT make again.

 

[Toysx2]

Howdy! Did you replace the throwout bearing with the same model? There are long ones and short ones. Also, it is possible to put the throwout bearing on backwards. John

Hello John,

Yes I did replace the throwout bearing with one of the same size and it appears to be on in the correct direction. I did not use the throwout bearing that came with the LUK clutch set. It appeared to have a plastic "collar", so I went and got one that is more "traditional" with the metal collar.

Ernie

 

[Toysx2]

It's also possible to put the clutch disk in backwards.
Ask me how I know that.
I spent 2 hours checking everything I did. Then, I pulled the tranny back out and sure as ****, the disk was in backwards.
Your symptoms match mine exactly.
LUK marks their disks to avoid this. I was in a hurry. I just slapped it on there.
It's a mistake I will NOT make again.

If anyone can put something together backwards, it is I!! 25-30 years ago I somehow managed to put the rotor in the distributor in backwards in the same truck. Mind you there is a square hole and a round hole for alignment purposes. I wondered why I had to re-do the spark plug wires to get it to run, but didn't catch on what I had done until several years later!!

I thought that I had checked out the disk on the clutch and had decided that it would only fit one way, but I guess that we'll see when I get it apart.........

 

[Cdaniel]

+1 on the backwards disc

 

[Toysx2]

+1 on the backwards disc

I kind of hope that you guys are right. It would at least give me a direction to point. Here are pix of the disk that I took out. I mounted the side in Disk 1 toward the pressure plate. The side in Disk 2 went to the flywheel. What do you think?


http://i46.photobucket.com/albums/f145/Toysx2/Disk1.jpg

http://i46.photobucket.com/albums/f145/Toysx2/Disk2.jpg

 

[Cdaniel]

I kind of hope that you guys are right. It would at least give me a direction to point. Here are pix of the disk that I took out. I mounted the side in Disk 1 toward the pressure plate. The side in Disk 2 went to the flywheel. What do you think?


http://i46.photobucket.com/albums/f145/Toysx2/Disk1.jpg

http://i46.photobucket.com/albums/f145/Toysx2/Disk2.jpg

That looks right to me.

Of the parts you replaced, do you still have the old to compare to the new?
You're sure the release bearing the same length?
Is the ball stud the same length? Is it tightend all the way?
Is there a difference in the length of the fork and/or the distance to the fulcrum point?

 

[Cdaniel]

Here's a cross section showing the whole setup

http://zot-art.com/cruiser page/misc project/clutch.jpg

 

[Toysx2]

That looks right to me.

Of the parts you replaced, do you still have the old to compare to the new?
You're sure the release bearing the same length?
Is the ball stud the same length? Is it tightend all the way?
Is there a difference in the length of the fork and/or the distance to the fulcrum point?

Darn!

Yes I still have the old parts. The release bearing is the same length. The ball stud has a different profile but it is the same length. It is tightened well.

The fork is not identical to the one I had, but it is the one listed on the main forum by Mark W. as the one to use--Pioneer CF-104. It also looks like the one sold by Advance Adapters for this application.

Thanks!

 

[Brian Macgyver]

I am not sure what your problem is, but I worked with Luk for several years. I once toured the Ohio factory. It was very impressive. I would not use any other clutch in my truck. Luk has been factory for GM as well as Toyo for several years. Luk does too many unique things to list here. Suffice it to say that it is the best clutch on the market by a considerable margin IMO.
Centerforce has a great idea. The units that they sell are basically a stock clutch with centrifigal weights that kick in at high RPMs. Great for high RPM race cars, and worthless for crawling. While theirs is a modified stock unit, they often do not use an OE clutch to modify. LUK is OEM for your GM drivetrain. Last I checked, Centerforce was modifying a Korean 12" clutch for use in GM trucks.
Now, to your troubles;
First, the problem that you have can happen even if the disc is disengaged. To find out, put the trans in gear with the engine off. Push the clutch in and have a friend try to move the truck. If it will roll, the disc is released. You may have a sticky pilot bearing or something hanging up.
Second, is the flywheel cut too thin? This will let the disc center hub hit the flywheel bolts. It will act like the disc is in backwards. Your old disc shown has a much lighter set of dampers than a Luk has. Luk's are heavy duty. If the flywheel is too thin a Luk will hit where a cheap replacement may not.
GM has different fork geometry for hydraulic and manual linkage. The fork angle is different, but they may look similar. They both fit, but the manual fork will not release a hydraulic clutch.
BTW, the late-model LUK TO bearing has a composite collar that reduces wear on several parts, but is very strong and heat-resistent. The bearing is NOT interchangeable with the earlier GM steel bearing. The clutch set that comes with the late style bearing has a lower finger height to compensate for the new TO bearing. The early bearing will not always release the newer pressure plate. LUK engineers these sets for GM to GM specs. No parts should be changed. The new clutches will fit GM's back to the 40's models, but only if the whole kit is used together.

 

[Toysx2]

I am not sure what your problem is, but I worked with Luk for several years. I once toured the Ohio factory. It was very impressive. I would not use any other clutch in my truck. Luk has been factory for GM as well as Toyo for several years. Luk does too many unique things to list here. Suffice it to say that it is the best clutch on the market by a considerable margin IMO.
Centerforce has a great idea. The units that they sell are basically a stock clutch with centrifigal weights that kick in at high RPMs. Great for high RPM race cars, and worthless for crawling. While theirs is a modified stock unit, they often do not use an OE clutch to modify. LUK is OEM for your GM drivetrain. Last I checked, Centerforce was modifying a Korean 12" clutch for use in GM trucks.
Now, to your troubles;
First, the problem that you have can happen even if the disc is disengaged. To find out, put the trans in gear with the engine off. Push the clutch in and have a friend try to move the truck. If it will roll, the disc is released. You may have a sticky pilot bearing or something hanging up.
Second, is the flywheel cut too thin? This will let the disc center hub hit the flywheel bolts. It will act like the disc is in backwards. Your old disc shown has a much lighter set of dampers than a Luk has. Luk's are heavy duty. If the flywheel is too thin a Luk will hit where a cheap replacement may not.
GM has different fork geometry for hydraulic and manual linkage. The fork angle is different, but they may look similar. They both fit, but the manual fork will not release a hydraulic clutch.
BTW, the late-model LUK TO bearing has a composite collar that reduces wear on several parts, but is very strong and heat-resistent. The bearing is NOT interchangeable with the earlier GM steel bearing. The clutch set that comes with the late style bearing has a lower finger height to compensate for the new TO bearing. The early bearing will not always release the newer pressure plate. LUK engineers these sets for GM to GM specs. No parts should be changed. The new clutches will fit GM's back to the 40's models, but only if the whole kit is used together.

Hey Brian!

That is great info!! I just wish that I could have seen it a few days earlier.... (Actually, the disc in the photos is a LUK--that's why I went back with the new one. I really only replaced it, because I was always told that if you ever have to work in that area of the truck--replace the clutch). I have taken every thing apart and will probably buy the Center Force. That clutch seems to be a known factor with actual part numbers available. I see posts on the main forum about other clutches, but I don't see any part numbers listed. I don't think that I have the energy to put the LUK back in with the correct TO Bearing....I am going to let the project set for a few days though. We'll see what happens in a few days. Thanks again.

 

[SC Forester]

]Hi all![/SIZE]

I am running a SB 350 engine connected to an SM465 Chevy transmission which in turn is connected the old style Toyota transfer case through an Advance Adapters adapter. These are in a 1968 FJ40. I recently pulled the transmission and transfer case to replace a leaking front seal on the transmission and the front seal on the transfer case. I replaced the clutch fork(cast iron with cast iron), clutch fork pivot ball, throwout bearing retainer, clutch(12” LUK with 12”LUK), and throwout bearing. When I got it all back together, the transmission would not shift. When the pedal is depressed the disk is still held tight between the pressure plate and the flywheel. I thought that I was not getting enough throw from the slave cylinder—slave piston was not traveling the full length of the cylinder bore. Now it had been shifting ok before I pulled the transmission. I adjusted the rods on the master and on the slave and bled the system with no improvement. I then read on the main forum to use a brake master cylinder to get more volume of fluid. I tried that and the piston is now coming half of its length out of the cylinder. The clutch disk still appears to be tight. So I am looking for suggestions on what to try next. I am ready to pull everything back out—except that I am not sure what to look for when I get it apart. Maybe its time to spring for Centerforce type of clutch? Thanks!

Replace “the front seal on the transfer case.”

I know this is a very old post but thought I’d ask here before I start a new one. I have an old style Advance Adapters adapter for my SM465 to 3 speed TC. It looks like it leaks bad out of the input shaft on the TC. There is no kind of seal there. I called AA and they said that is correct, there is no seal. The sealed bearing on the shaft is what seals it. It’s still got fluid coming up from underneath it though. I’m afraid it’s going to leak bad there when I get it all put together. I’m attaching a picture of it. Does anyone know if there should be seal in the hole for the input shaft on the TC when you are using the AA adapter? Thanks!

 

[Cdaniel]

It's been a really long time since I had that setup, but I don't remember a seal there. There isn't a good surface to seal to on the shaft.

The ID or OD fit of the bearing could be the leak path.

 

[SC Forester]

It's been a really long time since I had that setup, but I don't remember a seal there. There isn't a good surface to seal to on the shaft.

The ID or OD fit of the bearing could be the leak path.

Thanks for the reply on an old thread. It looks like that’s the bearing that came with the kit. I bought a replacement bearing yesterday but it didn’t look like it was going to fix the leak behind the current bearing.
How long did you run the AA setup? Did it leak bad for you? What are you running now?

 

[Cdaniel]

Thanks for the reply on an old thread. It looks like that’s the bearing that came with the kit. I bought a replacement bearing yesterday but it didn’t look like it was going to fix the leak behind the current bearing.
How long did you run the AA setup? Did it leak bad for you? What are you running now?

Actually now that I think about it I still have that adapter in there
It's just in front of an Orion now. I have leaks, but I think they come mostly from the SM465. Before when I had the 3 speed T-case I would get some oil transfer between the trans and T-case. I'm pretty sure I put a new bearing in the adapter. It's been years so the recall is foggy.

 

[SC Forester]

Actually now that I think about it I still have that adapter in there
It's just in front of an Orion now. I have leaks, but I think they come mostly from the SM465. Before when I had the 3 speed T-case I would get some oil transfer between the trans and T-case. I'm pretty sure I put a new bearing in the adapter. It's been years so the recall is foggy.

Ha ha! Do you know if you have the old style AA adapter? Mine has the AA input shaft in the TC and has a coupler that goes over it and over the output on the transmission (attached pics). I got a replacement bearing. It has a different color seal but Grainger said it’s the right part. It fits on the shaft so I guess I’ll swap those out and give it a try.

 

[Cdaniel]

I'm sure mine must be "old style" as I bought in the past century Your pics look like I remember.

 

[SC Forester]

I'm sure mine must be "old style" as I bought in the past century Your pics look like I remember.

Cool..thanks for the info. I may start a thread documenting my swap. It might be helpful to some other folks but it’ll probably be me asking questions and the Mud folks bailing me out.