Hi posted this on the roller section but as not a paving roller might have been missed. wanted to reach out again and see if anyone may have any insight, prevailing thought is possibly a hydraulic issue causing the motor to be turned into a pump and then resist not free spin. Hey anyone familiar with older stone rollers? or have any thoughts roller works great but keeps stripping out the coupler for the vibration on the drum. seeing as stone has gone belly up had a local company rebuild it, worked well for a while (rental yard so time is relative) stripped out again, company warrantied the coupler, try again lasts about same time (50 ish hours) and failed again, this time they replaced the small spline coupler and motor with a keyway set up worked well for a year but last rental it stripped out the keyway out. pulling the coupler means pulling the drum so is getting very old eccentric spins freely by hand, bearings all checked out, oil level is correct and clean, drained and refilled each time popular little machine and hard to replace but consistently causing issues, also has a odd chattering in the wheel drive motor area when switching from forwards to reverse at high speeds, checked out the unit and can not find a issue
Some pics. might help to show the coupler you're talking about. First thought is if the hyd. flow and pressure is correct for the roller. Switching direction at high speed sounds like it could certainly cause damage too.
the old coupler has been reworked into a keyway system, keyed shaft on the motor, going into a keyed hole. I will get some pictures once I take it apart, and try and find some old pics of the shaft, it always stripped the splines out of the drum side not stripped the motor shaft so original thought was a hardness issue. now suspecting likely more to do with a Hyd issue as seems to run well for a few hours each time before failing
How old is it. Looking at pictures of newer ones, they look like a Dynapac
exact age of the unit I am not sure, our system has it as a 2008 but that ight be when was added. finally had a chance to pull it back into our shop below are a couple pics of the unit and the coupler still inside the drum
jacked up unit and ran it with the vibe motor removed, vibe shaft stays stationary no sign of it turning which kinda kills my back pressure idea, also appears to be dead center no apparent misalignment.
Our old Raygo. The vibrator changes direction when the machine changes direction. I don't think all rollers do that, but I always stop the vibrator when I change direction. Common practice when rolling asphalt, and for fine grading so you don't get the bump when the roller stops. Does this machine do that? Maybe renters are not doing it, and the sudden direction change is killing it. I know a lot of guys will change direction on the pickup brooms on the bobcat, without pause, and it does damage after a while
oh I can say for sure that this doesn't stop on direction change, I will look into seeing if there is a way to get it to but doubt it will be quick enough.
sounds like it needs a soft starting relief valve set up with plenty of delay, especially given that there is no coupling element between the motor and the eccentric shaft to absorb some of the starting and stopping moments of inertia
when the eccentric weight is independent there is no inertia on the motor shaft. I thought there would be but with unit on jacks I checked and the eccentric weight was perfectly stationary no matter the movement of the drum. which makes sense for this unit not to have one from factory. system is pretty simple for it, a motor to a electric controlled spool valve block to the motor and then back to the block then to tank, both lines one the block appear to have relief valves on them, so new thing to check out, valve block is a vickers MCD-6667 will do some digging on it hopefully tomorrow
interesting fault, and you have ruled out some of the more common possibilities like misalignment or a bearing support starting to fail. you may need to put some gauges on and see what the operating pressures are. Keep us posted on the forum when you get time and let us know what you find.