ok , a bit more news, i removed the six poppets in the pump. two on one side two on the other and another two above the bottome ones? even though i dont know what to look for, one of them did looked scored around the top? is it meant to be like that? 1 took a bit of prising to get it out. i put em back in and it didnt seem to make any difference, then i went and tried to pull a tree stump out of the ground.grabbing it in the bucket and rocking back and forth. to my amazment when the stump came out the drive worked absolutley fine!!!!!!!!!!! that for a clpe of days, working hard as well...... then all of a sudden it came back, like the left drive motor is attatched to a hammer drill? was it cleaning out the poppets of the stump putting the drive under stress???? heeeelllllllpppppp its drivin me knutsssss
The wear mark you refer to, its like a full circle? if so, thats pretty much normal. Its the wear from where the poppet seats in the pump. It should still seal pretty well rite. If it did leak, it wouldn't be enough to bother things i wouldn't think. You did say it was quite tight, i'm not sure if thats normal. They should be free to move so they seal correctly.
I really have no idea what else it could be....... The knocking sound really sounds like the piston shoes snacking backwards into the yoke in the pump. It will sound and feel like a hammer drill. It still sounds like a charge pressure or replenishing valve problem. The thing that gets me is i'm sure both sides are fed through the same hole! So what affects one side, should affect the other exactly the same.
Maybee, a big maybee.... it could be the spring in the rotating group that holds it against the swash plate. This is inside the pump, so its not a small job! Like i said, a BIG maybee.
Honestly, it maybee the time to take it to the dealer to see what they think and get a pressure and flow test done. When you start pulling down a pump, if you do something wrong you will be up for BIG $$. They aren't that complicated, but you must make sure all the parts go in the rite places and around the rite way.
I can't remember if i asked before, but was the oil foamy at all? as there was a post a few days/weeks back from OLDMachinist and his 453F and his hydraulic pump. He re-kitted the pump and fixed the air problem. Air in your system could cause these problems your havig, but again, it SHOULD affect both sides the same.
If it was me, i'd go the pressure and flow test. At the least, a pressure test.
I hope you get it all sorted out!
Oh, the motor you re-built, what sort of seal was there where the shaft comes out that engages the gear box? I have a leaky motor that is slowly filling up the chain case of my 731 that i want to fix before selling it. I just don't want to go pulling the motors fully down just to replace 1 seal that can be done without pulling it to pieces. My service manual shows just a backup ring on the shaft, but there must be a seal there somewhere.