Finally got the old 8-inch cutter head to run smooth after a weird trick with the packing gland

We were on a job in the Sacramento River delta, and the main dredge pump had this nasty vibration that wouldn't quit. The usual checks on the shaft alignment and bearings came up fine. Out of ideas, I decided to try something my grandad mentioned once but I never tried: I backed off the packing gland nuts a full quarter turn and then retightened them in a star pattern, but only to hand-tight plus maybe an eighth of a turn with the wrench. I figured it was a long shot, but the vibration dropped by what felt like half almost right away. It seems the old packing had settled weird and was putting uneven pressure on the shaft. I always thought that gland had to be cranked down tight to stop leaks, but I guess a little play in the right spot can make a big difference. Has anyone else found that a slightly loose packing gland can actually help with pump vibration, or did I just get lucky this time?

2 comments

2 Comments

finleybutler6d ago

Yeah that trick is legit. Had a similar thing on a trash pump last season, it was humming like crazy. Loosened the gland nuts, gave the shaft a couple spins by hand, and snugged them back up just enough to see a slow drip. The shake went from "gonna shake itself apart" to a quiet rumble. Sometimes that old flax packing just needs to remember where it's supposed to sit.

sarah_johnson466d ago

Totally get that with the flax... makes me wonder if the heat from the shaking itself cooks the old packing dry and hard. Letting it spin free might not just reseat it, but break up that baked-on crust a little so it can actually absorb water again and get slick. Seen it where a packing that looked fine was just glazed over inside from running hot. That quiet rumble after is the sound of it finally getting lubricated.