Lifter function on a Rex 26-188 (Singer 16-188)

[FredSanford]

 

Greetings!  i'm restoring a "barn find" REX 26-188 (Singer 16-188, Nakajima TDU-N62, Consew 118, Chandler, Yakumo, National ...) .  Sews well but there is a lot of slack in the manual foot lifter lever, and when engaged the presser foot barely lifts off the needle plate in certain wheel positions (needle down).   Without the lifter functioning correctly I can't easily turn a corner while sewing. 

I've adjusted the clamp on the presser bar and set the vertical movement of the presser and walking feet approximately equal.   But there doesn't seem to be any adjustment to increase the overall vertical movement, or take the slack out of the lifter mechanism so the feet can be lifted higher.   

There is a small crank arm coming from the Take-up Cam (part T30D-1on page 2 of the TDU-N62 parts manual) that appears to drive the vertical movement of the feet.   Can the position of this be adjusted?  

Any Nakajima experts out there? 

Thanks!

P.S. I have the manual and exploded parts diagram.  I've read everything Nakajima-related on the web including this post but no help:

 

[FredSanford]

Here's some videos that show what I mean: 

Lots of slack in lifter, almost no lift

 

And a video of the feet walking.  Maybe the presser bar bracket needs more adjustment to raise the walking foot more and the presser foot less

Balance between presser and walking feet