PAWhiskeyfarmer
New member
- Joined
- Sep 13, 2018
- Messages
- 2
I'm not sure how my name in here changed, but I used to be Padeutzguy, I've mentioned these servos on a thread from 2013, just FYI. This summer I had a pump go south on me, long story short, due to money and lead times at the local hydro shops, I rebuilt both piston pumps and both drive motors and replaced the gear pump myself. A subcontracted mechanic at one of the shops went over the pumps with me, they aren't all that complex. There was a plate in one pump that was the problem, badly scored. Since all the pumps were disassembled, the shop wanted $8,000 for all 5 pieces and a month lead time. I didn't want to put the worn rotating groups back in it. A few mistakes along the way, like not putting the bolt in the adapter on the rear pump, since I didn't take it apart and it took 28 tons for the local machine shop to press off, anyway. It digs, spins it's wheels while loading if I'll let it, acts as it did when new. The only issue I can't resolve is the high pitched whine the motors make in high range, but the left motor does it all the time. It's so bad I have to wear hearing protection, mostly because it drives me nuts. Subbed mechanic went MIA, so I'm alone in this battle. 32 hours on the clock, same noise, same good performance. Last week it started really loosing hydraulic oil. It's running Lubrication Engineers oil, 4933, direct replacement for NH 134. This stuff is $25 a gallon, loosing a few gallons a day just isn't going to cut it. I just started removing the pumps, and the left servo was soaked, there is a trail/wash on the fuel tank under it of oil. Upon disassembly, the snap ring was broken and I see the oring has severe erosion. Could this loss of oil in the motor control cause that whining noise? I had assumed the oring between the pumps failed as did the rear pump main seal, as they had drips on them, now I have to wonder how much was coming from this servo, running down the pump bodies. How much pressure is up in the servos? 2,500lbs of pump pressure or the 500lbs of the charge pump? Thanks
