I just did some research. Hudson first started using a “wet” clutch in the 1920’s and continued until the merger with Nash. The friction material was cork inserts. It allowed for a smoother engagement with less chatter.
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Cork friction material??? I wonder how many miles those clutches lasted before needing a rebuild.
What material did the old two wheel bikes wither coaster brakes use?
There is a member of the Hudson-Essex-Terraplane club who rebuilds them. Apoarently, they last a long time.
If I remember right, the coaster brakes were metal. I think it was a cone or similar expanding against metal. My English bike had a front hand brake and rear coaster brake so rain wats no problem. Seems to me I had to rebuild the rear brake when it just locked up. No cork though.
Actually cork used to be used for lots of things in the old days. Remember the cork seals on bottle caps? Then came plastisol.
You may be right, but I seem to remember cross hatches making me think it was some other material.’
Remember them well they were a lot easier to open than they are now.
Actually, cork in motorcycle clutches gave very good service and if you’re old enough to have ever worked on older cars right up to '80s (maybe not that late…) most every gasket on an engine but the head gasket was cork.
I still have a couple of rolls of cork in various thickness to make custom gaskets from the "good-old-days…_
In the mid '60s I had a '58 Triumph Trophy 6 Motorcycle. It was a two carb, magneto’d 650cc bike that was reminiscent of Marlon Brando’s bike in the movie, “The Wild One.” Although his bike was a 1950 Triumph T6, a precursor to mine…
That was up to the moment that I wanted a bike more like Easy Rider than the Wild One and I rebuilt it into a chopper. Actually, I was ahead of Peter Fonda by a couple of years…
Part of the rebuild was a Cam, improved carbs, 750cc hop up kit (new cylinders and pistons), a 4-valve per cylinder head, and of course a new clutch.
The bike used a wet clutch, the friction plates were cork, and they had to be soaked in oil prior to installation.
I had friends and the advice of various shop owners that if you did not pre-soak them the cork could get burn spots on the plates and it would cause the clutch to chatter later on…
I soaked them and I never had clutch chatter…
Well now that bicycles have gotten into the thread, read a test of bikes in Consumer Reports, one brand was given a poor rating because the hand brakes were too good.
Bicyclists need the brakes to apply gradually, less with less hand brake pressure, more with more hand brake pressure, in order to maintain control of the bicycle. Perhaps the problematic bicycle brakes were grabbing too forcefully when first engaged.
Like I said my 3 speed had conventional rear brakes and a front hand brake. Had to be careful with the hand brake. Neighbor kid got on it and hit the front hand brake too hard and over he went. Surprised look on his face but only pride hurt.
Kinda all related though. You work on bikes first then maybe go karts, boats, model air planes, scooters and progress to cars. Skip some of that early experience and can be lost working on a car.
This is very interesting and I never would have thought cork could be used in something like this. I am familiar with the gaskets and have actually bought them made from cork in the past but heavy duty friction material requires an entirely different set of properties. It makes sense they have to be pre-soaked in oil and that this would only work in a wet-clutch system to keep it relatively cool.
I had coaster brakes as a kid and they always worked. I never had to take them apart so don’t know what was inside. Again, I bet this was some sort of basic “wet” setup.
I know cork was used in old steam boiler systems including those on ships such as the Titanic as insulation around the piping and funnels. One of the tell tale signs in the floating debris field was tons of cork released after it sank, the ship broke apart, and the funnels were destroyed during the process, releasing the insulation.
Then they went to asbestos for insulation and friction material. Cork must be a tougher material than I give it credit.
Being a kid of the '50s and '60s, I and my friends tore many a coaster brake apart. The old style bicycle coaster brake had an internal shoe that when you pushed the pedal backwards, it expanded the shoe to drag on the rotating inside of the hub.
There are folks, mostly old folks who reline really old, vintage cork clutch disc with wine bottle cork for vintage motorcycle where there are no replacement being made at all… I do not know how many American bikes had cork clutches originally, but Brit bikes had them and Royal Enfield continued the practice until the mid-'60s…
Just realize that not all cork is the same, as an easy example think about how dense a wine bottle cork is and then think about how "airy: a cork board is…
Below is a photo of clutch plates and discs that were “re-lined” using Wine Corks…
You tube it
Top computer assembly comes off with ease!!!
I’m in my 50s and I remember cork was used for valve cover gaskets and pan gaskets until just what SEEMED like just a few years ago 
During my apprenticeship, the trainers showed us how to make various gaskets out of cork and also those rolls of gasket paper
I’ve made a few gaskets out of cereal boxes and they seal up just fine and last a long time, for certain applications
I even used a “do not operate tag” to make a water pump gasket and it sealed up 100%
Whatever it takes
I’m guessing UTI does not teach those kind of skills 
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Unfortunately a lot schools now only teach you what to think not how to think… I was very lucky, my teacher was very good and making you think, at least with me anyway, he pushed me much harder then the people that cared more about making friends and playing games then learning…
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During my apprenticeship, I had to learn EVERYTHING . . . none of my parents, friends or relatives were mechanically inclined
Many of the other students in my apprenticeship came from backgrounds where their dad, uncle, etc was a mechanic, gas station owner, repair shop owner, etc. and they already had some fundamental understandings, unlike me
But many of those guys were goofing off, getting into physical fights, skipping class, telling the instructors what they could do to themselves, etc.
Predictably, many of them washed out as time passed
But this was literally my last chance, so I approached it accordingly and I’m still wrenching roughly 30 years later
Sometimes paying attention, willingness to learn, the right attitude and sheer perseverance will beat natural ability, mechanical background, etc. in the end . . . 
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That same thing happened to teenage me one time while riding my off-road motorcycle. I flew right over the handlebars and fortunately landed in a big pile of sand. IIRC the motorcycle’s front brake was controlled by the lever on the right handlebar, and the rear brake was the right-side foot pedal. The left handlebar lever was for the clutch.
Was that back in the altes land?
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I have done that also, in my more extravagent days I would buy the cork sheet and make my own gasket.
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