Re: clutch problem
 

Feel free to crawl under my truck and bench press that SM420 a few times!

Re: clutch problem
 

thanks Jim a, I'll try that

Re: clutch problem
 

It is important to make sure you have the full stroke range at both the master and slave cylinders.
There needs to be a little slack at the throwout bearing to protect it, but also enough travel of the slave rod to fully release the clutch disc.
I fought this situation for years and the fix. after waiting too long, was very difficult.

Re: clutch problem
 

When you say you can’t get it into gear with the engine running I assume you mean the gears grind when you try to engage? I believe ‘63 was the same as my ‘60. Is it a sm420 with a hydraulic clutch?

Sounds to me like the flywheel is not disengaging which is throwing the synchro off. Try cycling through all the gears with the engine off. Ending in 4th. Than start it up and see if you can put it back into 4th. Also try pumping up the clutch a few times before shifting. May or may not work but could give you a better idea of what is going on.

There is an adjustment nut where the slave cylinder meets the fork. Try setting it out further. Or master/slave cylinders could be on there last leg. Get eyes on the slave cylinder when someone pumps the clutch and see how much travel you get.

Re: clutch problem
 

thanks for the info