McLeod Adjustable Throw Out Bearing - How Much Free Play

Steve, I'm not familiar with that rig. Is the actual bearing a constant-contact type, or does it require some free play? My experience is when everything is nice 'n toasty-hot, about 0.020" or so of free play ib there will close up to zero and then the bearing will be spinning at clutch speed. What does McLeod say? I have a McLeod pressure plate but not their throwout bearing or disc.

Steve,

You are looking for a measurement of roughly .175"-.200" of clearance between the bearing and the fingers. This measurement will naturally be reduced by the fingers rising as the clutch wears. The actual freeplay can be adjusted normally once the trans is installed. The initial clearance measurement allows you to retain adequate freeplay as the clutch wears.

Ron

I'm not sure how to get an accurate measurement of the clearance because it is inside the cases.  It seems like it is approximately .175" - .200" but it could be less.  If it is less then I could take one shim out but the shim is .200".  Perhaps a little extra free play is better than not enough in this case because clutch wear reduces it over time.

You could probably use the same method for setting the initial freeplay as you would if you had a hydraulic T/O bearing. There are lots of YouTube videos on the subject. Keep in mind, too little freeplay could wear out clutch components prematurely but too much freeplay  won’t allow enough clutch disengagement, which could wear out synchros prematurely.

I watched a YouTube video as you suggested and it makes more sense now.  I will take measurements with the transmission out and set it as Ron recommended.

It'll never work using all the shims. Take it apart, call me tomorrow I'll walk you though it. I'm assuming you have the McLeod bearing shown here:

Sharkey, your picture shows the new version of my bearing.  Mine is NOS (new, old stock) and it came with the project.

I took the transmission off and measured it carefully.  There is .247" clearance.  All shims are in.  It seems like there will be far too much clearance if I pull a shim.

Thanks for your help.  Here are photos of my bearing.

And, it looks like your bearing might be for the internal slave cylinder while mine is for the external factory slave.

No need to overcomplicate, take out 2 shims, slide it all together, measure overall. Should measure approx 2.182, exactly what the car came new with. Pull the arm off the cross shaft, set it 12 o'clock straight up (if it's not already) or even one notch to the rear it'll still work. Either way you're good to go. From there set up the slave.

2 shims out measures 1.8225

1 shim out measures 2.020

No shims out measures 2.2205

It looks like the closest to stock is both shims in?

There you go you DID IT! Hooorrrayyyy you're good to go, that'll work fine.

The one shown we buy is from A-Tech but others sell them, then remove 2 shims. Work out the geometry from there once installed.

Sharkey, thanks for your help.

I connected everything related to the clutch and tested it, and it worked.  However, the amount of effort to push down the clutch pedal was unreasonable.  The car is a 72 pre L and did not come with clutch effort reduction.  I took the plunge and added the clutch effort reduction kit.  It was well worth it.  The clutch is still a little heavy but within expectation.

In my experience, Steve, the next time you have some cash, change just the pressure plate to a diaphragm type. The effort required from your leg is about half and the holding power will be the same. GM used this type for all their muscle cars.

McLeod used to make a Pantera specific diaphragm pressure plate but for some reason, it was not always in their catalogs. I had one for a decade and I loved it. I’m not sure if they still offer it so you’d have to call and ask. Dennis Quella would know too.

Thank you both.

The McLeod pressure plate that is in there now came with the project and is new.  I had it balanced with the engine components.  I will continue with it for the time being.

I have a diaphragm pressure plate (I think it is McLeod) with an internal slave in another Pantera.  I actually removed the effort reduction setup on  the car (it is a 74) and achieved better control of the clutch.  The car is operational.

Pretty soon I will be able to compare and contrast both types of clutches.

The part # for McLeod’s Pantera specific diaphragm clutch kit is 75210. Current price at Summit is $695. That includes pressure plate, dual friction disc, T/O bearing and alignment tool.

Summit shows it as a diaphragm clutch but the details say otherwise.  It says it is "Long":

You’re right! I suspect it is, indeed, a Long style PP but a phone call to McLeod would clear-up the matter.

I sent an e-mail to McLeod’s tech support and will post their answer here, when I receive it. If the part # I mentioned includes a Long style PP, I’ve asked for the part #’s of the appropriate Diagram PP items. I suspect they will recommend an 11” diaphragm PP with a Long style bolt pattern and a Pantera specific 11” disc but I’ll wait and see.

Hi stevebuchanan,

The Mcleod 75210 is a long style not a diaphragm clutch kit, I just return a 75110 kit (400 hp) to summit because I made the mistake, I think the McLeod diaphragm mechanism is the 360801 (3000 plate load) or or 360803 (2400 plate load) to be confirmed !

Good point on the clutch cover bolt pattern, David, since there are quite a few different bolt patterns and sizes used by clutch manufacturers, some of which won't fit a stock flywheel without redrilling.  And this is not a backyard job due to the possibility of screwing up the engine's balance. A new flywheel to match non-OEM bolt patterns can add many hundred dollars to a 'simple' clutch job.

There are special rounded-surface throwout bearings used with some diaphragm clutches. Due to the design, if a normal flat-face throwout is used on  a straight-arm diaphragm clutch, you can get a 'catch' in the clutch feel during shifting that bothers some people. The bearing needs to match the clutch type.

From Mcleod Tech:

Yes the 75210 does come with the Long Style Pressure Plate in Kit form.

We don’t offer a (Pantera) specific kit in diaphragm form.

However, kit # 75212 ((*diaphragm pressure plate + dual friction disc*) $455.00 Direct) with the (Pantera) specific T.O. Bearing 16525 ($115.00 Direct) will serve you well.

@bosswrench posted:

There are special rounded-surface throwout bearings used with some diaphragm clutches. Due to the design, if a normal flat-face throwout is used on  a straight-arm diaphragm clutch, you can get a 'catch' in the clutch feel during shifting that bothers some people. The bearing needs to match the clutch type.

I've experienced the "catch" Jack mentioned above and it was so miserable, IMO, that I removed the offending PP without even driving the car with it! That was a SPEC diaphragm pressure plate and it was incompatible with my Mcleod hydraulic (flat faced) T/O bearing. I replaced the PP with a Mcleod diaphragm unit that had curved fingers and the release action was then perfect.

FYI, the part # Mcleod tech recommended (# 75212) does have curved fingers, so it will work with their Pantera specific, flat faced T/O bearing (# 16525).