Hey guys, just looking for a little insight on a mid 70's Pettibone 36mk.. It's developed a low growl and slight vibration, especially when cold and intensifies with rpm and load. I'm pretty sure one of the two main pumps is on its way out.. Just looking for second opinion/other possibilities I may be over looking. Thanks!
Is this a crane that you own? It could well be one of the pumps. I know these things can be a bugger to work on, but I believe I'd pull the pumps off and take them apart for inspection. It's better for the hyd system to catch pump failure before it fills the system with metal grindings and grenade fragments.
I don't own it.. The marina I work for does, I run and maintain it though. While a lot of the things on this machine are a pain to work on, the pumps shouldn't be to big of a deal. We shall see though, I've said that before.. Good winter project i guess seeing as the boats don't do much this time of year.
Ok, sounds like you have fun. I haven't worked on many "bones", but a plenty Galion, P&H, Grove, and Link Belt RT's. The old Galion 150A was a PITA to work on. Can't say for certain, but it could be you have gear pumps on it and the pump bushings are getting worn. This makes the shafts move sideways inside the pump body and the gears will rub the inside of the pump housing making that growling noise. It intensifies under lifting load because pressure pushes the shafts even more into the housing. It might save you grief just to take them down and inspect them.
Thanks, Appreciate the insight.. Will tear into it after the holidays..
Id be pulling the pumps back and having a look at whatever (spline,lovejoy,etc) is coupling them to the power source. Quick,easy and often the source of noise when cold.
I know this is an old thread but be sure the input strainer for the pump/s is not restricted AT ALL. If so the restriction will cause the pump/s to cavitate and cause noise. This will be worse if the hyd oil is cold and viscosity is higher. The input strainer is primarily to protect the pump from sucking in anything that may damage it and not a really fine filter like the other system "filters" are.