Help with clutch problem

W-motorhead

 
Supporting Member 1
Dear 348/409ers,
Although my fresh 409 sounds terrific, a clutch problem is keeping my '63 Biscayne off the road. During the rebuild, I installed a new Centerforce 10.5-inch clutch (see attached photo) onto a refaced stock flywheel, driving a Borg Warner T10 4-speed tranny (overhauled by Kajun Jon Bergeron). When I use the LONG throwout bearing (recommended by the guys at Show Cars), the clutch slips so severely that I can barely creep down the street. When I use the SHORT throwout bearing (recommended by the tech advisor at Centerforce), I cannot disengage the clutch and shift into gear, even after maximum clutch pedal adjustment. Does anyone have advice that can get me out of CLUTCH HELL!
Dan Fults
 

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Ishiftem

Well Known Member
Supporting Member 2
How much free play did you have with the long bearing? Zero? Did you have a lot with the short bearing? It just sounds like the linkage is adjusted incorrectly. I have always used the shorter bearing with a high cone type diaphragm.
 

64ss409

Well Known Member
Supporting Member 9
A few years ago I had a 10.5 Centerforce like yours. I used the short T.O. bearing. Is the clutch fork sitting on the pivot ball like it should be?
 

jbschneeweis

Well Known Member
Dan: I have the same clutch you have & we used short bearing & I also had a t10 4 speed, now I have a M21 hooked up. My worked great with both. I agree with everyone else that something is not seated properly. The guy who installed mine is Karl at API in Sandy. He is at the SEMA & should be back this week. We can talk to him. Give me a call on Monday on my cell (801)918-6415 & lets see if we can figure this out.

Joel
 

4onthefloor

Well Known Member
Supporting Member 1
I had a similar strange problem this year with the same setup. I had to change out my pilot bushing and when I put the whole thing back together with a new short bearing it would not realease the clutch. Toook it apart again and looked everything over. Everything looked correct and was in its correct place. Used an old input shaft to align clutch and put it back together. Still would not realease clutch to put it in gear. Pissed me off so I rolled it out onto the driveway after getting the engine warm. Shut it off,put it in gear, pushed clutch pedal in and started it up...fully expecting it to lurch forward but it did not....the problem fixed itself and damn if I can figure out what the heck was wrong. You may want to try it yourself. Leave yourself room so you dont drive thru the garage in case it doesnt work for you ! Im thinking that even though all the diaphragm leaves were even and it was torqued down properly that somehow the pressure plate was slightly cocked in there but for the life of me I have no idea what was wrong.
 

PAINTJOHN1

Well Known Member
Supporting Member 2
Was your car always a 409 car?.Was the engine a 6 cyl. or small block originally?.If it was did you change the Z bar?.The 409 ues a different Z bar in the 63 and 64 years,also possibly in the 65 years as well..The small block and 6 cylinder Z bar will work,but you will have problems like you are talking about,clutch not grabbing probably,shudder,hard to get into gear..John
 
Dan, after reading other's comments here, I would be suspicious of the release fork in the bell housing.
A mistake I made years ago, was using a large aluminum bell housing from a late 70's Camaro, along with it's corresponding release fork. I learned the hard way, that the newer release fork is longer, and will not transmit enough travel to the release bearing.
 

DonSSDD

Well Known Member
Supporting Member 2
The components of the clutch linkage have to match each other, ie. all be from the same setup. The geometry of the rods, z bar and clutch fork is all the same, since all the old trannies, bell housings and the ball mount position on the block are the same on any old small block or W or big block.A different shape for a fork is compensated for by different rod lengths or different clocking of the arms on the z bar.

I would bet Aubrey is correct.
 

W-motorhead

 
Supporting Member 1
Many thanks, guys. The experience and helpfulness of the 348/409 group is inspiring. Evidence is pointing to the clutchfork as the culprit.

I did replace the clutchfork because the spring clip, which attaches the fork to the pivot ball on the bell housing, was missing from the original part. Aubrey Bruneau called my attention to shape differences between the original and the replacement part, which I bought from Show Cars.

It looks like I'll be on my back on the garage floor again because Aubrey advised me that the tranny must be dropped to replace the clutch fork. Does anyone know if the clutchfork can be extracted through the opening in the back of the bell housing or is it necessary to detach the bell housing from the engine block? I pray that the latter is not the case. :pray

I'd like to think that Paint John's suggestion about replacing the Z-bar would correct the geometry. I'll measure my existing Z-bar to make sure it is correct for the 409.

I gather that everyone agrees that the Centerforce clutch is OK to keep.

Dan Fults
 

Phil Reed

Well Seasoned Member
Supporting Member 10
Dan...you will need the 409 specific bellcrank and corresponding clutch fork and lower cluctch fork pushrod. Should just drop in and go!!!!
 

DonSSDD

Well Known Member
Supporting Member 2
What's different Phil? Is there something different on the 63-64 frame from a 62 and a 59?

My 63 409 worked fine in my 59 with all the 59 stuff in place from the 283. I think I have a 63 z bar from a 6 cylinder, can't remember but I think the rods are from the 63 too, and I am using a clutch fork with the pin, same as in the 59. I have a Center Force clutch in the 62.

Don
 

PAINTJOHN1

Well Known Member
Supporting Member 2
Dan.the Z bars are the same demensions(width and length),the levers are at different angles then the small block and the 6 cylinder.
 

Dick MacKenzie

Well Known Member
Supporting Member 9
Show cars has a diagram showing the difference in bell cranks for our "X" frame cars. It's a little confusing since they obviously make every effort to include all the available bellcranks on the same page. The one you're interested in at the last two. The bottom one is a 409 item for 62 to 64 cars and the one above is for 'all others'. You'll notice the length of the drop bar is 2 7/8" on the 409 bar and 3 3/8" on all others.

 

chevy man

Well Known Member
Supporting Member 9
Dan................. What Phil is telling you would be the first thing to change. This will correct your problem, but be sure to check and make sure your t.o. brg. is correct.
 

62impala409

 
Supporting Member 1
Dan................. What Phil is telling you would be the first thing to change. This will correct your problem, but be sure to check and make sure your t.o. brg. is correct.
As a general rule, the 3 arm style pressure plate requires the short bearing and the diaphragm style pressure plate requires the long bearing. The 3 piece clutch kits available will include the correct bearing. Leo
 
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