Yes, It was my first thought, and dealer agree that the play in the piston connections is too much, we disassembled it and there is absolutely NO bushing. Just a hole and the pin goes through it. The Branson also confirmed there is no bushing supposed to be
Also, if you look at the second video where i recorded where the pistons are going out, you can notice that the piston goes out fast at the beginning, then slows down. hard to see, but it is there.
The outer pivot pins on the cylinder should fit tight in that hole in the swing frame. If wear makes that fit sloppy - caused by not greasing the zerk there enough or doing a lot of side sweeping - then the usual fix is to replace the bushings.
BTW, backhoes aren't set up to do heavy side sweeping. It makes new ones old before their time.
Sincy yours doesn't have bushings on those external pivot pins.... if you keep it youcan put bushings there if you are handy that way.
Are you saying that there is also endplay in the piston connecting rod? Can you wiggle the piston rod back and forth inside the cylinder with just hand pressure? If so, very very not good.... But it would sure explain how it could change sweep speed. The fix involves openin up the cylinder to get to the insides so as to be able to tighten the rod nut.
Now there is some update:
Today i was working with the BH for 4-5 hours. What i noticed and it made me think, it is not that the boom slows down, it looks like it starts too fast, then after 1/5 of the turn it gets to the normal speed, then at the last 1/5 turn it jumps to run too fast.
Glad you were working it. After all, it isn't perfect but beats no backhoe. We had an old beat up 3pt hoe for years that was sloppy as hell but still useful. It would shimmy like a snake. Finally sold it to a friend who used it another decade. Eventually he and I both bought JD310s with thumbs. Over beers last week he and I were trying to figure out what took us to long to get smart.
It is like excessive pressure going to the rams at the beginning and at the end of the swing/cycle.. I was running 1800-2100RPM.
first it was jumping like creasy, then go to the acceptable speed, then jumps again and slams to the tractor so hard, it even bent the step. the buffer could not the impact so violent it was, See the picture.
Can it be excessive pressure?
It is probably not excessive pressure. Back in message #27 you mentioned that the BH pressure was coming from the PB port on the FEL control valve. That PB port pressure is controlled by the same pressure relief valve that sets your working maximum pressure everywhere on the tractor. My guess is that although the relief valve is set to around 2800 psi , you are probably using half that or less to make an unloaded swing motion. Only way to get it to max pressure for an instant is by stalling the swing with a heavy load. A simple change in speed won't go that high.
So if it is not excessive pressure, why is it slamming the stops? Well, two reasons - but only #1 counts.
1. Your hoe should have always had heavy rubber stops at both ends of the travel so that it cannot slam into the steps. Most backhoes have that. Sounds like someone forgot to put yours on. You could buy ones from from someone else's hoe then find the holes where yours should have been and mount them. Or else drill a hole & install a set.
Or use rubber stops for sliding barn doors....
Or a piece of 2x4 with a chunk from an old tire screwed onto it... Or whatever.
Do something, even if it is to wrap a towel around the step. That impact at full swing is half of what is chewing up your cylinder pivot pins. And it could have also loosened up the piston rod in the cylinder - or broke something inside there.
2. The other reason for slamming is design. Nothing you can do about that. The original swing geometry should have been designed so that a constant piston motion gives your hoe a controlled speed of swing even though the motion is through an uneven arc. Getting that sort of thing right requires some real pencil and paper skuill sweat and the designer probably assumed rubber stops plus no odd wear or slop. That's the engineering part. Not much you can do with that except use what you have, fix, and improve it.
Be interesting to see what the pressure show.
rScotty
