Mopar Flathead 6 Clutch Disc Specs?

[keithb7]

Mopar 9 ¼” , 10 spline clutch disc used on L6 engines with manual 3 speed from at least ‘37 to ‘55.  

 

Does anyone know what the wear specs are on the friction material thicknesses? Measuring both sides, as installed on a disc, I mic’d up 0.2907”. Wondering if there is a way to tell approx % worn? Or minimum spec? Thx. 

 

 

Edited January 10, 2020 by keithb7 (see edit history)

[c49er]

No total thickness specified but shows each asbestos plate thickness as .133"

This for a 9-1/4" 1937 Ply clutch.

National Data Service Book1948

[Mikefit]

When in doubt let there be no doubt. Put in new

[Rusty_OToole]

If it is worn down to the rivets replace it. If not, use your own judgement. I would say if it is more than half worn might as well put in a new one while you have it apart. Depending how much you drive and how long you plan to keep the car, you will be sore at yourself if you have to take it apart again.

[plymouthcranbrook]

Having learned the hard way I would never go to the trouble of removing a transmission just to check the condition of the disk.  Replace everything wear related and be done with it. The pressure plate might be weak or the throw out bearing near death.  I once when much younger took a Plymouth New Process four speed out to replace a howling throw out bearing. Two months later had to do it again as the pressure plate failed. Shoot, the last time I changed a clutch in 2006 I even did the pilot bearing, something I never fooled with before. Cheap(comparatively) insurance.

Edited January 12, 2020 by plymouthcranbrook (see edit history)

[keithb7]

Thanks for your replies folks. 

The tranny came out as it had excessive counter shaft thrust washer wear. Symptoms were howling in 1st and 2nd gear. I rebuilt the tranny. The throwout bearing was also worn and is being replaced. 
 

From my perspective I am of the mindset that this is a hobby. I am reviewing an old tired mostly stock condition car. It will be a summer cruiser once in a while. Currently I am going over all the mechanical parts of the car. Making it safe and reliable. I enjoy wrenching on it as much as driving it. The clutch disc will be replaced. The pressure plate, maybe at another time. The car might see 300 miles in a year. Maybe. The tranny came out easily in about an hour. I am not concerned about removing it again in the the future if i need to get back into the clutch. 
 

I’m wrenching and trying to watch my costs. As you know it’s easy to throw $20K into a 4dr sedan. I’m trying to build a fun driver, rarely seen on the roads today. Without tossing to much money into the wind.