Main spring rubbing

[WJMurray]

This has got me puzzled. Once I got the tracks installed I noticed that the main springs rub on the back of the track frame. The crawler is going to have a loader (Haven't found one yet ), so the final drives are slopped forward. I included a pic. Any help would be greatly appreciated.
WJMurray

[chrisvdv]

Happy New Year!
I have seen them rub on a great percentage of machines I have inspected over the years. I guess it's a tight fit and with a wee bit of bend or play here and there, it is very difficult to have that all line up perfectly.

What loader do you want? I have a Ware 3-WI here needing renovation but in good shape (still tight at all the pins). The best and strongest of the OC3 loaders. I also have a 3-HI if you want more height and less bucket. Both are very capable.

You know my email...with best wishes, Chris

[Jack in NB]

That rubbing is caused by wear on the front and bottom of the rear track hangars, the boss on the inside of the final drive casting and to a lesser degree on the steel block (Trunnion?) on the outside of the rear axle.

The inside usually wears more than the outside, both because of the softer cast iron on the final drive, and because of the dirt getting into the wear surface. The outer bearing is somewhat shielded by the cover plate. That gives the treads a definite toe-in, the bottom more than the top, often to the point of wearing into the dozer push arms.

It also allows the track frame to move forward, contacting the back of the knee action spring, and on one of mine, the sprocket actually started cutting into the track frame.

The cause - poor design. As delivered, there was no dirt protection over the inner bearing surface, and the oil fittings were installed on only one side of the track hangars - oiling the front on one side and the rear on the other. There was an oil track in a steel sleeve originally installed that was supposed to distribute oil around the bearing surface, but it usually got chewed up in the first few years, and the oil filler button fitting on the front usually plugged up with dirt in the first few hours. Net result - no lubrication on the front and bottom surfaces, and wear that is difficult to repair.

I built up the final drive bosses on mine with braze, built a portable lathe to turn them back to round (pressed out the axle and inserted a stub arbour to carry a fly cutter), built up the outer blocks and trued them up. and built up and cut out the track hangars to fit. Then put grease fittings on both sides of the track hangars. Tried rubber dirt shields over the inside; didn't last. So now I grease the inners every couple of hours to blow out the dirt.

[hotratz]

Very good information Jack. Thanks for posting this.

[mikegt4]

Another place to check is the lower end of the main spring assembly.  Because the lower mounting bolt is offset toward the rear of the track frame the stem can bend causing the spring to rub the track frame.

[Cplwill]

  Just throwing this question out there. How important is the need for the main springs on a Cletrac? I mean it is basically a "suspension system" that allows the track frames to rise and fall independently in the front, and the rear track hangers are the pivot points. The reason i ask, is that a lot of the old crawlers i have seen are fixed solid to the frame and don't have the kind of wear issues that these do. Is there any benefit to this system over a fixed system? Just wondering.

[Blake Malkamaki]

The springs are so the tracks articulate over uneven ground. Loaders are generally mounted solid with no movement of the track frames. Some later dozers - like my OC-12 - have walking beam suspension that goes from one track frame to the other, pivoting under the tractor belly. This allows one track frame to rise up and the other to drop, thus compensating for uneven ground, yet preventing the front of the tractor from nose-diving when the blade is moved up and down, and to help keep a better grade while grading.

Blake

[Cplwill]

Thanks for the response Blake,
  I am about 20% into my restoration and was considering the possibility of doing the fixed system because my final drives are badly worn at the inner track hangers. Seems like a lot of work to build them up, true them up, and find some sort of bushing material, just to have them wear out again. The other idea i had was to machine the hangers then use my Babbit material to pour a bushing onto the final drives. This would eliminate the need for building them up and machining them. Keep them greased and they should last a long time. Just throwing out some ideas.

[oliverchris]

According to an Oliver OC3 type-written memo to dealers I have, the mainsprings allow for up to 3 inches of oscillation, they call it. As  Blake says, giving more traction on uneven ground and a smoother ride with less strain on the mainframe. They compare it to a JD40C with solid frame that cannot ride out a bump on one side without the other side also rising up. I will post another note about this memo re. Ware 3-WI loaders.