MH-50 clutch issue

I have a MH-50 tractor. On the dash panel it reads MH-50, s/n SGM 507364. From what information I have been able to find, I believe this is a 1956 Massey Harris. It was running great last year and I used it to haul wood and cut the fields. In the year I have owned it, I have not been able to engage the PTO with the engine running, I have to shut off the tractor, engage the PTO and restart the tractor and at the end of last summer I began having additional clutch issues. I can put the tractor into neutral and start it no problem but the clutch won"t disengage so I can put in into gear. I can put in into gear with the tractor shut off and then start the tractor but that"s rediculously dangerous as not much will stop it once it"s moving. I assume I need to replace the clutch so I went online and and purchased a service manual through All States Ag Parts. The front cover says it covers the MF35, MF50, MH50 and Ferguson TO35. The clutch section of this manual apparently only covers tractors from s/n 515395 and up with a combination coil and Belleville spring dual clutch. Can anyone tell me what clutch would be in my tractor before I start tearing it apart? Any assistance and guidance would be greatly appreciated. Thanks!

Best way to find what style clutch is to remove the four bolt cover at the bottom, then you can see if main clutch has coil springs or bellville. The partsbook shows bellville on both plates, I would still look to make sure.

Thanks,
I will pull the cover this weekend and have a look.

With dieseltech's idea, you have to lay in the mud. I got a cleaner idea. Since you have a manual, which you get an A + for, try adjusting the clutch. Just the one nut and bolt on the pedal. But really, few will engage well at more than a slow idle speed, after keeping your foot hard on the pedal for several seconds, even if adjusted perfectly.
This is a 2 stage clutch. Your serial number tells us that...should be... what's in there...

You may have the style clutch in Tonys pictures or you may have this earlier style shown here. This is from a late 1955 TO35. The service book should have details about both the old and new clutch types.

Dan