I recently bought a 580 Super M backhoe with about 7300 hours on it. The bucket curl linkage seemed looser than others I have had. If I move the bucket cylinders sideways the two flat bars on either side move quite a bit where the attach to the loader arms. I removed the 4 bolts that hold the 4 large flat bars (item 12 in attached parts diagram) so I could remove the cylinders and linkage. The 4 hollow bushings between the flat bars (2 per side) look in good condition with minimal wear. On The top ones still are a fairly tight fit in the holes in the bucket link ( item 2 in diagram) The problem seems to be the bottom bushings where they go through the loader arms on each side - the bushings are approximately 1-3/8 diameter and the holes in the loader arms are approximately 1-7/8 inch. That is approx 1/2 inch clearance and seems excessive - At first I thought maybe there was a missing bushing that goes between the hollow bushing and the hole in the loader arms but I dont see one in the parts diagram. The 1-7/8 holes in the loader arm are still round - I would have expected them to be egg shaped if they had worn that much. Appreciate if anyone knows if this clearance is normal in this location in the linkage ? I have a lathe and could machine an additional bushing to take up the clearance if it should be a tighter fit but dont want to do that if there is a reason for this much clearance.
No It is not normal. How tight are the bushings where the bars mount on the cylinders (#15).
Thanks for the quick reply Tinkerer - the cylinder trunion bushings in the center of the flat bars are good - very little clearance. There is a little bit of clearance between the top bushings and the long links that go the bucket - maybe 1/32 to 1/16. It is only the lower bushings that have the excessive clearance to the loader arm holes. If it was all wear I would have expected the holes to be egg shaped with the most wear on the front and rear of the hole as that is where the most force is applied as the the bucket is curled up or down. The main force down is the weight of cylinder and linkage and not much of any force up so I wouldnt expect the loader arm holes to be worn much up or down but the hoes are almost perfectly round. If they should be tight I could machine a steel bushing and install in the loader arms with a tight fit on the outside and normal a bit of clearance on the inside diameter to the hollow bushing between the side plates. I just wanted to confirm that the large clearance is not normal - only reason I could think of was that it might be a way of allowing the force applied by the 2 bucket cylinder to equalize or maybe to provide some free movement in the linkage so you can "bang" the bucket against the stops when fully curled down by quickly reversing the loader hydraulic lever to dislodge any material stuck in the bucket. Is there any place I can find what the bore in the loader arms should be so I can machine a bushing with the correct inside diameter ?
There are bushes fitted at the tilt linkage pivots. They are made from a bronze & they literally disappear into thin air. Part #100696A1 (38.41mm ID x 47.65mm OD x 28.6mm L)
Thats great Alrman, problem solved. I didnt look at that parts diagram because it referred to loader lift linkage. Strange the parts diagram for the bucket linkage shows all the other parts and the loader arms but not these bushings. I see you are in Qld, beautfiul country. I worked in Brisbane for a year back in the early 2000's on a mining project.