My Putzmeister tk50 main cylinders seem to go out of sync every 4 strokes it pauses and forces them back into sync   I’m assuming it’s an internal leak in one of the cylinders. But any input is appreciated  

Nobody ? 

Did you observe anything out of place on the pressure gauges, accumulator pressure in particular?

If there was a leak from the pistons, it would pour hydraulic oil into the water box, did you notice anything strange there?

Another option would be the proximity sensors faulting. I think the manual explains how to check for that.

Anyways those are usually the main suspects

I’m thinking the piston seals internally allowing oil past the piston . Not the external seals. Proximity swatches are all working fine. If you watch the cylinders move they go out of sync then after a few strokes it loads down and forces them back into alignment. I’ve checked all four check valves and they appear to be working no broken springs or visible damage  

If it's indeed an internal leak. There is a way to make sure that. You put the pump in test stroke mode, what it does it maxes out the pressure on each cylinder in turn, kind of similar to when you get plugged. If you don't observe any loss of pressure then you're fine on that front. I would recommend to advise the manual again for that since every pump is a bit different and I have some experience with TK40.

does this causes your hoses line to surge? I have to anchor or tie down my line from surging.  Nitrogen is good, above 95. I replaced all 3 prox sensors and two relay, but still the same.

No my lines dont surge at all  on the forth stroke it pauses and loads down while the cylinders realign. I spoke to Putz yesterday and they confirmed what I thought an internal leak on a cylinder. He said about her tell tale sign is one cylinder creeping while the pump is stopped  

you may want to check with putz but I do believe there are some check valves on the material cylinders that can also cause this , that's the easiest place to start .

Could be the piston seals, highly unlikely though, as they are very reliable on a putz.  Did you check the quarter turn valve at the top of the driver side pumping cylinder to make sure it didn't go put in the "off" position somehow?  I'd take it apart and make sure it didn't come apart and get blocked internally somehow.  Do you have 4 prox swtiches at top and bottom of same cylinder?  Or do you have 6 top, and bottom of same, and 2 a the waterbox side of the other one?  

When it makes up the oil, does it go really slowly and high pressure, or does it do it kind of quickly?  Tough to explain, but I'm sure you've seen it make up oil in the shop, is it at that pace or do you have to look at the rods just to see if it is moving or not?

I don’t think there is a 1/4 turn valve on the tk 50  it only has 3 proximity switches 2 in one cylinder and one in the other.  I spoke with putz and he agreed it’s likely bypassing a piston in the cylinder  and every 4 th stroke is what he called the stroke correction so it forces them back into sync. While sitting running one cylinder creeps as well  he said that’s another sign of a bad piston seal  

I don’t think there is a 1/4 turn valve on the tk 50  it only has 3 proximity switches 2 in one cylinder and one in the other.  I spoke with putz and he agreed it’s likely bypassing a piston in the cylinder  and every 4 th stroke is what he called the stroke correction so it forces them back into sync. While sitting running one cylinder creeps as well  he said that’s another sign of a bad piston seal