Hi,

My car is a stock 1968 L36 convertible, with a 4 speed manual transmission.

I have removed transmission for replacing the throwout bearing, but while I'm at it I will replace the clutch and pressure plate also. I'm planning to order from Corvette America, and must ask if this is the right place for a OEM-style replacement clutch?

I noticed they had two different versions, 43929 and 43927. I'm hesitating on which one I need? Since I live in northern Europe it will be sort of impossible to return anything.

If someone can give their advice I would be glad.

Thanks.

Martin

 

Dont they have auto parts stores over there?.......its a stock 11 inch Chevy assembly......the difference may be from the transmissions main drive....either a coarse spline or fine and should correctly be the course spline main drive for a 1968...And they both use and the short throw out bearing......and get your flywheel resurfaced

 

Yep - Call you local parts stores.

 

I used a LUK clutch, who made the OEM one. Should be dealers over there...they are sold worldwide.

http://catalog.schaeffler-aftermarke...&engine=427%22

 

I've used Ram clutch assemblies and have not had any problems,they have oem and muscle car set ups that are affordable.Try Jegs or Summit both good companies for price and customer service. Mike

 

Hello Martin
One is a 10.5'' and the other is a 11'' clutch
Your car "should" have the 11'' model, but first check your bellhousing, the last three digits must be 621 (the larger type of bellhousing).
Also count the splines on the transmission input shaft. Your's should have 10 splines, but if the transmission is from a 1970 or later it will have 26 splines

Regards
Karsten

 

I'm in UK - I chose Centerforce clutch and flywheel - handles far more power than stock unit yet is lighter in operation.

 

Hi everyone,

I have the 11" clutch, 10 spline shaft as expected. My mistake not checking my usual local parts supplier, they had Sachs clutches and pressure plates in stock for a very good price (which is not always the case in Sweden). So I will get this from them instead.

I know there are numerous threads regarding resurfacing the flywheel, most seem to recommend to resurface to be safe. However, my existing clutch is not "extremely" worn, and there are no scores or massive signs of overheating on my flywheel, so some of the old school guys over here just looks strange on me when mentioning resurfacing the flywheel. I will call a local machine shop tomorrow and check what they charge.

Martin

 

Only the L-88`s had a 10.5 disc and a approximately 13 lb, flywheel...all the rest were 11.0

 

Finally I found time to finish the clutch replacement. I used a standard Sachs clutch kit from our local parts store.

It all works well. Sort of. I might have made an annoying mistake. I purchased a new clutch fork and pivot stud from Corvette America. Since it was quite some time I disassembled the clutch, I forgot to compare the pivot stud length with my old one. What a mistake. CA says their stud fits all cars 56-81, but after browsing around on CF it becomes more and more apparent that this is not correct. I checked my old stud, it measured 1-3/8". I bet the CA stud is 1-1/2". My symptoms now is that I have to jam the pedal to the floor mat to have a full release. If I adjust so I have the clutch release earlier on the pedal stroke, I have 0 pedal freeplay, and inspecting with a flashlight in the clucth fork entry hole on the bellhousing it's obvious that the throwout bearing rides on the diaphragm fingers. Not good. If I back off the adjustment to avoid this, I have to shove the pedal in the floor mat between shifts.

Could this 1/8" length difference be that important, and mess up the geometry that bad?

I noticed Corvette Central carried the two different studs. But many other warehouses seems to only offer one version. That's very unfortunate since this part is not easy to change, I don't know if it is possible without transmission removal?

Regards,

Martin

 

First you should disassemble your clutch linkage and check for wear. Even a small amount of wear can cause problems. On my car I found that the pin on the lower linkage had worn half way through! I replaced it with the new style adjustable linkage.

There are different lengths of pivot ball studs available. The longer one, I believe, is if you use a scatter shield without the block saver plate?
I wen't through the same thing with a Sachs clutch, only worse.
The one I got wouldn't even fit without compressing the clutch fingers. Even then it wouldn't disengage enough to be able to shift gears.
The clutch fingers weren't stiff enough, giving a longer travel than the Corvette linkage can provide (even without any wear).
I had to scrap mine and reuse my old Centerforce clutch. This was after I corrected the linkage problems.

 

Do you remember what Sachs kit you used? What Engine and transmission do you have?

You just adressed my basic reason for starting this thread - are there Corvette specific issues that could cause problems?

I have a stock bellhousing, stock linkage with no significant wear. All I want is a new clutch, stock style.

My concern right now is that if I change to the 1-3/8" stud - I will still have to press the pedal in the floormat to have a full release, becuause of the reason you mentioned.

I will readjust so the release bearing is borderline to touching the clutch fingers and then see if I can get a full release and at what pedal position. With the currently installed ball pivot stud. If I can't get a release with this adjustment - I can't see how the shorter stud could help me, it's only 1/8" shorter??

Martin

 

Usually if you are having release problems, then you would actually need the ball stud to be longer. So without the longer ball stud you are using now, your release problem would be worse. Are you sure that the throwout bearing you are using is the same as before? Also is the clutch finger height the same as the old clutch. When underneath the car, check that the clutch fork is slighty pointing forward when you are holding the throwout bearing against the clutch fingers.

Bill

 

My kit was K5552-03, 69 Big Block with a Muncie M20.
My advice would be to return the Sucks clutch and get a Centerforce kit. The Centerforce clutch has the correct dimension. The Sachs kit doesn't work.

 

This evening I did the following:

- I have the exact same clutch kit from Sachs as Danish Shark.

- Unhooked the clutch linkage rod that connects to the clutch fork and inspected the amount of free-play between the clutch fingers and release bearing. Approx. 1/4" play available. The clutch fork points slightly forward when bearing is 1/4" away from fingers.

- Hooked the linkage back up and adjusted the clutch so the bearing is very close to touching the fingers, but NO bearing to finger contact when pedal is released. With this adjustment the actual clutch release only comes on the last 1" of pedal travel, ie closest to the floor mat. The car is driveable, but it's extremely annoying.

- Clutch linkage is in good shape, no pronounced wear & tear.

So, basically, I'm probably lucky I did get the long pivot stud like 69ttop502 says, otherwise I would have an even worst case. I can't imagine the shorter stud can change the fork travel at all?

And, Danish Shark's comment is exactly what I experience on my car (1968 427/390). It feels like the pressure plate fingers does not release enough with the available throw the Corvette clutch offers.

So, once again a Corvette part that obviously is not tested once on a real car. Not once. It feels more like a rule rather than exception these days. It's a complete guess and waste of money when it comes to the modern aftermarket business.

The Centerforce kit - what part no. is it that we might think works better? I'm only after a stock style clutch.

I can't see any other explanation than the one Danish Shark says:

SACHS clutch kit K5552-03 DOES NOT work on a Corvette. Junk. No matter what the parts guys claims.

Martin

 

I sourced my dual friction Centerforce clutch and flywheel from Summit Racing.
http://www.summitracing.com/parts/ct...te?prefilter=1
As I mentioned the pedal pressure is a little lighter that the stock clutch I replaced. It copes very well with my 565 lb/fts torque and disengages cleanly at all revs up to 6400 - nice progressive action too.

 

Martin

One of the top Corvette experts/restorers in the country ordered the LUK Repset for my car. I gave you the link in my above post. The clutch works fine in my rebuilt L-36 with an M-21. The flywheel was resurfaced and the bellhousing was re-centered...because my crankshaft was polished and new main bearings installed. I still have my original ball stud but had to replace the clutch fork because the clip broke when a spring in the original pressure plate came loose.

The LUK Repset is a stock clutch.

 

Thanks. I will try and see where I can find one. Approximately at what pedal position can you freely shift from neutral into reverse without grinding?

Martin

 

http://forums.corvetteforum.com/c1-a...ent-issue.html

Too bad I didn't read the above thread earlier....

/Martin

 

Martin

It's only time and money. I am no expert on these matters...I just try to make sure that any advice I receive is from one.

Things warming up over there in Sweden, other than the "immigrants" burning cars? My brother-in-law in Grums keeps me up to date regularly on Skype.

This is the LUK Repset installed. Note the curved fingers.