Good job and nice rig!
Does your 40 have a rear disc conversion "kit"? If so, from what company?
@Pighead , I saw you have discs on your 55 in the rear too. Kit?
I just installed new drum brake cylinders (Japanese aftermarket, all 4) in the rear of my 76, and bleeding them gave me ( and a trusted mechanic) fits! Yes, I tried all the tips I could find here on Mud too.
I've done it in the past and never had an issue like this time.
I'm going to be shopping for a disc brake conversion kit soon, to put on the shelf for the next time a brake cylinder leaks or can't be adjusted.