So I'm working on a 1953 w136 170d- with the om636.

I'm putting in a om636 engine from a 180d ponton.

The original 170d's clutch pedal could be pressed easy with one finger. I noticed the pressure plate forks take less pressure to press than that 180d plate. Like half!

Both plates are the same number.

Is my old one just worn out? Or is it lighter due to a different design?

Was the 170's clutch working? If you can push a clutch pedal with one finger its either vacuum boosted or has no hydraulic oil/linkage connected.

Yeah it was working, its a manual clutch- no hydraulics of any kind. I took the plunge and used the firmer pressure plate from the 180d. I'll let you know when I get it all hooked up.

You have likely solved the issue. However, I used to work at A1 Clutch in Buena Park CA.

On Car clutches they threw the springs away because it was cheaper to replace them then to pay someone to check them and store them someplace.

If you had the specs for the spring you would use a device like the one where they test the spring tension of engine valve springs. At X amount of compression there would be a pressure range that was good or not.

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84 300D, 82 Volvo 244Gl Diesel

I had thought about tearing both plates apart, and testing the springs. I don't think that data is out there for the w136 cars. Pontons and up yes. I'll find out soon enough.

I was not suggesting you should do that. Just wanted to say what was done.

The other issue is where would you find new springs?

In the car section you put the whole clutch on a table and it pneumatically collapsed all of the springs so you could take it apart. In the Truck section where I was I had a similar thing but had to hand crank it.

Not sure on the car clutches but on the trucks there was often levers the tips of which needed the height adjusted. And you needed a spec for that

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84 300D, 82 Volvo 244Gl Diesel