I am currently renting a Link-Belt 3400Q machine (roughly 7600 hrs) with a 60' long reach boom on it for doing some dugout cleanouts. I've noticed that the swing is very slow on it. I haven't had that much experience with excavators (been running them about 1-1/2 years now) but compared to our Cat it's very slow. Cat is an older 235 with standard boom/stick. Is this normal of a long reach? The place we're renting it from says that it is normal for a long reach to be slow. I also noticed that while swinging if I use the stick function or boom function at the same time it picks up speed a little bit. We are debating about buying the machine but don't want to if the swing motor is getting weak. Thanks guys. Chris
Just a thought has it got a boom or dipper over slew priority function,
Most machines will have a spec for rounds per min while swinging, some machines also can slow the swing and boom raise faster, slower boom and faster swing. I have run over 25 different 50-60 foot long reaches and all were a little different swing wise. 60' is a lot of boom/stick out there, if it's getting 6-8 rounds per min, type of bucket and material handled, factory machine or a retro fit.
I talked to a guy I know that works on all different breeds of equipment and he said it could possibly be a valve in the swing motor that is sticking and then occasionally opening up hence why I would see it being slow most of the time but sometimes full speed. Does anyone have a schematic or know what valve this could be? He said similar to a travel motor, it has to have pressure to overcome it?
Counterbalance valve, which is usually two opposing piloted relief cartridges in a manifold block or the motor head itself. Possible just from use the relief valves in the circuit are weak, and need to be adjusted/replaced.
Would anyone happen to have a schematic of this or where to check the hyd relief pressures at?