LUK vs National T.O. bearings differences!

[David M.]

As I do with anything I disassemble I compare the old to new parts just so I dont have to preform a repair twice. I was excited when I bought the LUK Rep Set with everything in it. I had the parts guy put the National TO bearing back on the shelf. Looks like Im going back to get it. Look at the height difference. Look at the plastic fork collar, yes plastic verses OEM metal. Look at the fact I can off center the new bearing! This must be chineasium junk? Anyone use this plastic garbage? Should I (reluctantly) use it as it did come as a kit? Or is this a question for LUK? Plastic TO bearing...now Ive seen it all...jezz.

edit>Disgruntled email sent to LUK. Ill update if they respond. At minimum I hope I can cross-ref a metal release bearing?

[Jim D.]

Re: LUK vs National T.O. bearings differences!

I've used "this plastic garbage" included with LUK clutches in the last 5 clutch installs and have never had a problem with any of them. Actually, the "composite plastic" portion of the bearing, not plastic, is superior to metal as far as I'm concerned. I would choose it over an all metal bearing all day long.

Do you think that an OEM clutch supplier would use a POS T/O bearing to go with their quality clutch kits?

[David M.]

Re: LUK vs National T.O. bearings differences!

Jim,
That is my hope that they have done their engineering home work and not gone down the see-no-evil bean counter road to save .03 cents/unit. Being a ME/EE I'm well aware of material improvements/strengths/continuous design Improvements et al. Can you understand my concern when comparing the OEM to this "new, improved" design? Its nearly 100 thou shorter than what I took out. Thats darn close to the .125 adjustment at the clevis for free play.

As finicky as these manual clutch adjustments are did you have to alter the adjustment procedure at all?

The composite (blow molded polymer composite plastic) IS on the release side of the bearing. Im concerned that I can force the bearing off center. Is this by design? Id certainly be in my comfort zone with some engineering specifications on this component. Maybe thats the problem Im an anal engineer and very old school when it come to my muscle cars.

Knowing you've not encountered adverse affects is comforting.

Thanks for providing this feed back Jim.

[Joe L.]

Re: LUK vs National T.O. bearings differences!

Jim,
That is my hope that they have done their engineering home work and not gone down the see-no-evil bean counter road to save .03 cents/unit. Being a ME/EE I'm well aware of material improvements/strengths/continuous design Improvements et al. Can you understand my concern when comparing the OEM to this "new, improved" design? Its nearly 100 thou shorter than what I took out. Thats darn close to the .125 adjustment at the clevis for free play.

As finicky as these manual clutch adjustments are did you have to alter the adjustment procedure at all?

The composite (blow molded polymer composite plastic) IS on the release side of the bearing. Im concerned that I can force the bearing off center. Is this by design? Id certainly be in my comfort zone with some engineering specifications on this component. Maybe thats the problem Im an anal engineer and very old school when it come to my muscle cars.

Knowing you've not encountered adverse affects is comforting.

Thanks for providing this feed back Jim.

Dave------


The release bearings in your photo appear to be sitting on a soft surface and I can't tell if the bottom surfaces are actually at the same level. I'm not so sure that there really is a significant difference in length between them.

The composite/metal release bearings are becoming quite common. In fact, the Timken brand release bearings are currently of this type.

The "off-center" configuration of this bearing is called "self-aligning". That's a good feature that original bearings did not have.

[Richard M.]

Re: LUK vs National T.O. bearings differences!

I have used the LUK clutch kit supplied bearings with industrial plastic collars for years with no problems. My first one gave me the same reaction, surprised that it was plastic.They have performed flawlessly.

Now, as far as your bearing height difference is concerned, as Joe said it's hard to see exactly the height difference, but my suspicion is your old bearing is the taller design made to be used in conjunction with a flat fingered diaphragm clutch disk. Your LUK bearing came with a bent fingered diaphragm clutch disk configured properly for Corvette. The shorter bearing is what you MUST use with a bent finger clutch.

I suspect your old clutch disk was the flat finger type and the tall bearing was used to make it functional, or you simply had the wrong bearing installed with the correct bent finer clutch disk.

Rich

edit.....Good info from John Hinckley here.....

https://www.forums.ncrs.org/showthread.php?107168-64-327-365-thow-out-bearing-question&p=716554#post716554

[David M.]

Re: LUK vs National T.O. bearings differences!

Rich, Joe, I measured the stack-up on the bench, the orange shop towel provided a good back ground contrast. Rich you are in fact correct I didn't notice that finger difference. Great advice/in site guys. Invaluable service here. The self centering bearing makes sense. If you ever need similar 64-72 GM A body tech info, Im well versed and provide this type of expertise in the Ford Truck, Olds, Buick Pontiac, (BOP) community, some Chevy too! Also well versed with GM TH350,400,700R4 2004Rs as well, glad to return the favors.

Dave

[Joe L.]

Re: LUK vs National T.O. bearings differences!

I have used the LUK clutch kit supplied bearings with industrial plastic collars for years with no problems. My first one gave me the same reaction, surprised that it was plastic.They have performed flawlessly.

Now, as far as your bearing height difference is concerned, as Joe said it's hard to see exactly the height difference, but my suspicion is your old bearing is the taller design made to be used in conjunction with a flat fingered diaphragm clutch disk. Your LUK bearing came with a bent fingered diaphragm clutch disk configured properly for Corvette. The shorter bearing is what you MUST use with a bent finger clutch.

I suspect your old clutch disk was the flat finger type and the tall bearing was used to make it functional, or you simply had the wrong bearing installed with the correct bent finer clutch disk.

Rich

edit.....Good info from John Hinckley here.....
https://www.forums.ncrs.org/showthre...554#post716554

Rich-------


The difference in length of the 2 clutch release bearings is greater than that seen in the above photo and reported. The L1955-81 release bearing was 1-1/4" or 1-7/32" (the 1-7/32" size used from 1964-81 was discontinued by GM years ago and replaced by the 1-1/4" size). The other size, used on E1955 Corvettes and many other Chevrolet applications in later years, is 1-7/8". The difference in the 2 bearings reported by Dave might be the difference between the 1-1/4" and 1-7/32" bearings, both of which may be available in the aftermarket. As far as GM goes, these bearings can be used interchangeably, at least for 1964-81 Corvette applications.

[David M.]

Re: LUK vs National T.O. bearings differences!

The saga continues. Installing the LUK clutch was fairly easy. BUT Im having one hell of a time getting the last 1/4 inch of the trans to suck up to the bell housing. I wrestled with it until I ran out of gas and threw in the towel for the day. I can not get the pilot shaft to find is home. Any tips to getting the trans to slam home???

Im no novice with stick or auto trans installs. I've only ever had one other stick in a Chevelle give me this much trouble. That was because I was sold the wrong parts.
This is the LUK 04-021 repset. I questioned the disc orientation thinking I may have it in backwards thus the trans snout may have been contacting/interfering with the center of the disc not allowing that final ka-thunk Im home sound we mechanics like. The disc is in right. No direction in this kit

The TO bearing is in correctly sitting on top of the spring as all TOBs should.

So I pulled it apart for a sanity check on the disc. Its in right. Sure be nice if LUK stamped the pressure plate side like they did with the flywheel side. Cant see stamped "Flywheel side" when its installed. Alas the disc will only go in one way...the fatter side towards the pressure plate. No room in the flywheel for the "fat side". SO its obvious.

So I fiddled with the alignment tool and clutch as I was sucking it down to the flywheel the second time. Ill try to explain what I did next.... I counteracted gravity and favored the slop in the up direction both with the alignment tool and the pressure plate. The hope was a truer parallel alignment with the disc and trans input shaft.

This is where I ran outa steam and didnt have another battle with trans left in me. So it may go in tomorrow???

One more Q: The rep set came with two pilot bushings. Im assuming only the smaller one which fits into the crank is required? There is a second larger OD bushing Im assuming is for a larger pilot hole drilled crank shaft? Again some directions in this kit would be nice! The LUK website is totally useless and a google search yielded zero. grrrr.

Any tips on how to get this trans to find its home would be greatly appreciated.

[Joe L.]

Re: LUK vs National T.O. bearings differences!

The saga continues. Installing the LUK clutch was fairly easy. BUT Im having one hell of a time getting the last 1/4 inch of the trans to suck up to the bell housing. I wrestled with it until I ran out of gas and threw in the towel for the day. I can not get the pilot shaft to find is home. Any tips to getting the trans to slam home???

Im no novice with stick or auto trans installs. I've only ever had one other stick in a Chevelle give me this much trouble. That was because I was sold the wrong parts.
This is the LUK 04-021 repset. I questioned the disc orientation thinking I may have it in backwards thus the trans snout may have been contacting/interfering with the center of the disc not allowing that final ka-thunk Im home sound we mechanics like. The disc is in right. No direction in this kit

The TO bearing is in correctly sitting on top of the spring as all TOBs should.

So I pulled it apart for a sanity check on the disc. Its in right. Sure be nice if LUK stamped the pressure plate side like they did with the flywheel side. Cant see stamped "Flywheel side" when its installed. Alas the disc will only go in one way...the fatter side towards the pressure plate. No room in the flywheel for the "fat side". SO its obvious.

So I fiddled with the alignment tool and clutch as I was sucking it down to the flywheel the second time. Ill try to explain what I did next.... I counteracted gravity and favored the slop in the up direction both with the alignment tool and the pressure plate. The hope was a truer parallel alignment with the disc and trans input shaft.

This is where I ran outa steam and didnt have another battle with trans left in me. So it may go in tomorrow???

One more Q: The rep set came with two pilot bushings. Im assuming only the smaller one which fits into the crank is required? There is a second larger OD bushing Im assuming is for a larger pilot hole drilled crank shaft? Again some directions in this kit would be nice! The LUK website is totally useless and a google search yielded zero. grrrr.

Any tips on how to get this trans to find its home would be greatly appreciated.

David----------


First of all, your problem has nothing to do with the LUK clutch; I've had the same experience using all GM clutch components. Lots of other folks have, too.

The pilot bushing that fits into your crank is the one to use. The other one is for cranks with a larger pilot bushing bore. As I recall, these cranks were originally used for Turbo-Glide automatic trans applications but, over the years, have found their way to manual trans applications.

Are you using the plastic alignment tool supplied with the clutch set? If so, I have found those to be problematic. Your best alignment tool is an old input shaft of the correct size and spline count (10, in your case). Check the pilot bushing ID with the alignment tool. If the alignment tool fits into the pilot bushing, your transmission's pilot shaft should, too.

[Richard M.]

Re: LUK vs National T.O. bearings differences!

To help alignment I use two 1/2"-13 alignment studs apx 4" long. The studs are made by cutting the heads off of 2 long bolts. I cut a slot in the ends to use a screwdriver to install them and also to remove them after the transmission is home. I install those in the upper left and right bell housing threaded bolt locations. This also helps to keep it from rotating. Wiggling the tail of the trans while pushing in usually helps.

They are a great aid to align the transmission and help distribute the weight upward which is the difficult part of installation. I replace them one at a time with the stock bolts when I'm certain it's home.

Rich

[Jim D.]

Re: LUK vs National T.O. bearings differences!

With the clutch linkage hooked up, have someone depress the clutch pedal and the trans. should be able to go in the rest of the way. If not, the issue is probably the pilot bushing. I had one that was too tight in the crank when installed. It decreased the inner diameter and the trans wouldn't go in all the way.

[David M.]

Re: LUK vs National T.O. bearings differences!

Thanks Joe. The LUK does appear to be a high quality unit for sure Im happy with it. I test fit the pilot bushing to the trans input snout, it fit snug as intended(learned to test fit everything many moons ago). Yes, Im using the alignment tool verses a cut off shaft. Cant imaging trying to install a trans without one. Agreed the plastic tool is inferior to an old input shaft. I have good parallel alignment I think. Thanks for straightening out the issue with pilot bushings. I've never encountered the larger one. I assumed it was there for a different application. Be nice if LUK put some basic directions with the kit. Its been a while since Ive messed with a stick car.

Rich the stud idea is a good one. Ill take some bolts with me today if Jim's suggestion doesn't work.

Jim thanks you've just jogged my old memory. Yes I believe depressing the clutch should do the trick.

Again thank you everyone for the advice. Ill close this loop hopefully successfully today.

[Michael M.]

[David M.]

Re: LUK vs National T.O. bearings differences!

Yes I go out of my way to steer clear of chineasuim or offshore in general.

Update. The trans dropped in upon depressing the clutch. Haven't started it yet to see how it feels/sounds. I still need to check the clutch free travel. I believe I also conquered the 3 speeds shift rod adjustments as well. Ill follow up on everything today...hopefully its a successful one?

[David M.]

Re: LUK vs National T.O. bearings differences!

Success. Thanks all for the wealth of info. Shes almost back on the road.
Now to close the loop....

What we learned:
1. The 3 speed shifter aligns the same way a 4 speed does by inserting a gauge into the shifter to obtain true neutral, (Rectangular slot in the shifter housing). Then you make the rods line up with the trans shift levers with both levers in neutral. Note...make sure the gauge inserts all the way through both gates.

2. The shift rods made contact with each other causing lack of full 1st gear engagement and the infamous popping out of 2nd when into the gas going around the corner. (The shifter and rods are not worn out and in factory orientation per the "book"). After aligning the shifter and inserting the rods on to the trans shift levers I had dad sit in the car up on the lift and row through the gears. Sure enough the 2/3 rod was contacting the 1/R rod bolt at the clevis where it attaches to the top of 1/R trans lever. The fix. I tried installing the bolt both ways with the OEM acorn nut. That didnt work. So I tried a regular nut with a thinner split lock. That was better. I finally removed the 2/3 trans shift lever and slightly tweaked in in a vice to favor the tunnel verses the trans. Fixed! All gears engage smoothly as father GM intended.

3. The LUK clutch definitely is smoother than the junk GP clutch I removed. Do not mix match TO bearings. The LUK TO bearing is specially designed for the bent finger diaphragm clutch whereas the one I removed had the straight fingers and thicker all metal TO bearing.

4. Rookie mistake....if you cant get that last 1/4 inch of the trans to seat onto the bell housing...depress the clutch...ka-thunk...in it goes.

5. The clutch disc can physically only be installed in one direction. No brainer there, but I of course second guessed myself for no reason other than to get frustrate and loose hair.

6. Dont bother with the tunnel insulation. I messed up a $50 part by the time I was done wrestling in the trans. Had to bandage it up with foil tape. The fix....install dynamat or pull the body. Optional: Install the removable cross member that would make this job soooo much easier.

Again thanks for all the help I hope to return the favor soon.

Dave