On a four in one (4 in 1) bucket or Clam Bucket: Was wondering if anybody noticed the (forced) 'creep' opening of the bucket bottom (clam portion) while backdragging? The one on my 580K tries to open about an inch or so, then seems to stay at that spot until I catch it. I rented the same 310G a few times and it has this condition and is pretty noticeable, with the clam opening about 6 inches while backdragging about 30 feet. The above condition for both machines is with the loader on float.... If you have noticed this and fixed/corrected it, what was the cause?
I'm wondering if it may be an operator fault oceanbob. When you close the clam, in the full rollback position, gravity will close it before the cylinders fill with oil - so when closing the clam hold the lever for that extra second, until you hear the relief pressure go off. Just seems funny that 2 machines have the same problem.
ALRman is right..the cylinders are cavitating.the fix that I have osed quite often is to put oriface discs in the fittings on the rod end of the cylinders to slow down the return oil from the rod end of the cylinder while the head end is filling. Other than that easy fix,the G backhoes had an issue with the piston nut backing off and allowing oil bypass in the cylinder.If you feel that tha cylnders are bypassing internally,Isolated them individually and then remove the suspect from the machine.Drain it out and then remove the fitting from the head end (bottom).look in the port and move the rod in until you can see the nut holding the piston on,You should be able to tell quite quick if its loose or not. If its not, a quick piston reseal is in order,since you identified this cylinder as the leaker anyways...
why not use the 4-1 to its full potential and back grade with it open utilising 2 edge,s i would also go with holding the lever in the shut position for a few more seconds
I will re-examine the operator technique.....although it seems to me the exact second the clam closes, the pressure would essentially instantly "spike up" to the relief (system or circuit, whichever is less) pressure? Seems it be difficult to remove one's hand from the control prior to this occurring? I am surmising once the clam is closed, it is closed as tight as it is going to be....and that upon backdragging, it is opening due to force being applied to the rod which is secured by the control valve - unless the control valve is leaking by? or perhaps the "circuit relief & or load check" is bypassing? This causes me more confusion because how then does the oil enter the other part (eg above the piston) of the cylinder? * RE: Backdragging with the open clam is a method that works OK for hard soils, in this situation was working in moist silty sand and the open clam method tends to dig in quite a bit.....I was also warned that if there is a piece of concrete or a pipe (barely hidden below the surface) that "hooks" the open clam, it could bend it. Another drawback to the open clam backdrag is the difficulty to see what is happening. * The type of closed clam backdragging (initially mentioned) using the bucket tip and bucket bottom is analogous to using a steel trowel on stiff concrete or similar to a drywall trowel....bucket bottom angle closer to perpendicular: removes or scrapes away more material....angle closer to parallel: removes less material.
well i suppose if you were doing about 30 mph you may have a chance of bending it bit of a myth i think i do not really find a problem in loose material ,the beauty of doing it with the clam open ,is you can grade , cut ,carry and level all in one go if your are in lumpy ground ,you can move the larger lumps with the rear cutting edge ,then grade and carry with the clam cutting edge i prefer to to the main of the fine grading going forwards ,and just backdrag some fine material if i need to remove wheel marks as for not seeing it ,thats where feel comes into it at the end of the day , its what works best for you cheers graham