just wondering what ever ones thoughts are on these,seems like they do not last has long has any machine with the low track system.is there more leverage on them because of the high track set up?? some have said you could grease them every three hours and they still will have premature failure,its just two grease seals and a cyntrifical bearing,why does the grease setup not work?? one fellow hef member said he broke 4 or 5 equalizer bars on a 9r in 10000 hrs, it just seems like cat would build a better system. has any one come up with any ideas how to make these better, grease zerks top and bottom or different bearing set ups, I know they changed to a oil bath system are these any better from what you have seen.??
Yair . . . earthscratcher I have never seen the set up but, for the life of me, I cannot understand how they work with fixed ends . . . it seems geometrically impossible. There was not much to go wrong on the oval tracks as the equaliser or cross-spring played no part in track alignment the ends just slipping back and forth across the frame. I'm going to check a hi-track out some time to see if I can get my head around it, here they are few and far between. Cheers.
The pinned ends reduce the strain on the pivot shafts by holding the track frames in alignment. The older oval track machines had a dead axle and swing frame arrangement. The dead axle went through the final drive and the swing frames hooked up behind the final under the machine. I've seen a couple of D9s pulling single shank rippers in hard rock bend the dead axles. From my experience the problems that show up on hard bars comes from pushing the blade into the ground until the whole front of the machine is pushed up into the air. This overextends the give in the center bushing and throws strain into the spherical ball bushings on the ends. The other big factor is that the ends are always covered in dirt and debris and they don't get lubed when they should be. The problem is the same on both the high drive Cats and the oval track Komatsu dozers. As I recall the old TD25 Internationals had side rollers where the hard bars would be on the Cats. The each track frame was held in alignment without affecting the other or throwing all that force into the final drives. That part was a lot easier for pulling the swing frames for undercarriage replacement. Pulling the ball on the back end though more than made up for easier side roller.
Yair . . . Gotcha John C. The part I don't understand is how the system deals with the geometrical fact that in any position but dead level any given point on the bar will be closer to the centreline of the tractor. I can't get my head around the type of spherical bushing or bearing that could accommodate the different arc dimensions. Cheers.
I have often wondered that myself Scrub but it seems to work,must be enough slack, slop, stretch , flex to allow it to work. I don't think the track frames have as much vertical movement as the older styles did . I was on a D 600D Hanomag dozer that had a pinned equaliser bar and it had very little vertical track frame movement. IH was the best with their vertical slide set up, just replace the wear strips when they wore out.
Yair . . . Gotcha R.D.G013 I never had much to do with the red machines . . . Massey Ferguson had a slide system on their machines that worked pretty well. I must say though that in many thousands of hours with the conventional diagonal brace system as used by Cat, Allis and Komatsu I never had any recurrent issues, an occasional broken pivot pin and broken spring leaves on the Allis's and that's about all. We ended up welding all the spring leaves together on the twenty ones so in effect they became an equalizer bar. Biggest issue was bending track frames where they divide at the idler. Cheers.
I haven't had a Cat bar out but the center bushing in a Komatsu was multiple layers of rubber each separated by a steel sleeve. As I recall the bushing was pressed into the hard bar, the bar set in the machine and then the center mount pin was pressed into the bosses and the bushing. I seem to remember that after the first one failed an update came out that made the pin slip fit in the bushing and a grease track was part of the new pin. The fitting was remote mounted. Since the pin was covered up by the belly pans you couldn't tell if the pin was getting grease or not. It was easy to tell when the center was broke. The front of the machine would come up when pushing down on the blade but the hard bar and track frames would stay in one place. What I have seen on most of the Cats is the end bushings getting broke. Testing them is the same process with pushing down on the blade and watching the ends.
I'll echo John C's comments. To break one hard bar in a high drive Cat might be put down to bad luck, to break four or five is down to either bad maintenance, bad operation, or a combination of both IMHO. They are pretty resilient but won't stand for continuous abuse.
Regarding the question of the geometry, the part most of you are missing is that the flex in the system comes at the pivot shaft. There is an allowable amount of play in the pivot shaft bearing to let the track frame move as needed. It is only a small amount of movement at the rear to allow the needed angle to change. In addition, I may be the one referenced in the OP's post. I had a D-9R, purchased at close to 10,000 hrs, and in the service records I received with the machine, found the equalizer bar had been replaced 5 times. In my years with the machine, I put about another 9,000 hrs on it and suffered another 5 broken equalizer bars. Re Nige's comment above, I attribute a lot of it to harsh operating conditions. two or three of the broken bars occurred doing emergency flood control work, working in running water and round cobble rock with no fines to cushion the impact. That is as rough as it gets for the bottom of the tractor. There were many other rock jobs involved in the life of this machine, but I feel that the design of this part was not up to the task.
To be fair Cat did redesign the ends of the hard bar on the D9R and T models to include more robust ends, new bearings, and an improved method of greasing them. That worked on our D9's. I have not heard of a similar issue on smaller machines like the D6.