Greetings Gents, I have a Cat 933G 42A machine.  As many are aware, the hydraulic pump is front mounted and driven via a short driveshaft assembly from the front crank pulley.  As I went to change the water pump and generator drive belts I found one of the U joints seized.  As I attempted to press the U joint apart I managed to break the yoke flange end.  The postings on Facebook yielded a replacement assembly. Took the shaft assembly to a local driveline repair company and had them disassemble it.  Told them of my internet conversations stating that a Moog 870 or a GMB 250-0870 could be potential replacements.  In speaking today with driveline company, they believe the caps of the spiders are some form of a taper fit with a short section of spline to help secure them.  He did not believe an 870 Moog would work as he thinks the snap ring is more decoration as the parts are not correct from an interference fit standpoint.
I’m certain Cat will tell me these parts are NLA.  My only other thoughts would be getting a machine shop to resize the bores to correct interference fit sizes and rebuild with appropriate press fit spiders.  I knew these parts were unobtanium when I got into this and was hoping for a suitable replacement in available sizes.
Any thoughts, comments, or advice?  Thanks, Dave

 

Something strange about that 3K8807 u-joint assembly
Apparently the center section flange end has two 3K9532 bearings and the rest (6) are 4F3057.
Interchange manuals show a UJ870 replacement but that would only work on one end or the (7/8" bores only)
I don't believe they are anything but straight bore pressed fit bearings, regardless of size.
Maybe the answer is to make all 7/8" bore

OM I read that too with the 6 of one and 2 of another. I’m with you that these two sizes have the driveline guys scratching their heads. I will see about getting them all cleaned up to 7/8” (.875) and go from there. I didn’t think they were any tapered press fit. Might have been a little wonky after they got it apart? Anyhow, thank you for confirming my thought process.
Dave