Undercarriage?

[bdog2]

Picked up a '77 JD 550 dozer. Sprockets are worn severely to the point that you can see its increasing chain wear. My question is it common to go thru multiple sprockets throughout the life of the undercarriage. Would it make sense to change only sprockets at the moment and extend the life of my chain or would new sprockets just get chewed up in no time at all. Basically is it normal to go thru multiple sprockets before it's time for a complete undercarriage rebuild? Thanks

[Lavoy]

Sprockets are more likely to be worn by the tracks, not the other way around. If one is shot, both are likelly shot.
Lavoy

[LeonardL]

In my opinion?? No... you don't go through multiple sprockets on a given chain. I suspect you have bad pins and bushings as well. Maybe even bad rails. I never had a scenario where I had to replace multiple sprockets on a given undercarriage. I suppose if the machine is in an environment where there is a lot of excessive abrasion going on that you would wear one out ahead of the pins and bushings. I'm not saying it isn't possible but I've just never seen it happen.

It is pretty typical for when a sprocket is done then the track pins and bushings are done as well. There used to be companies around who would turn the pins and bushings 180 degrees and put a new sprocket on and go again. Or you could have new pins and bushings installed by these same folks. Not many places still doing that these days. Now days when the sprockets along with the pins and bushings are toast you just buy new rails and sprockets.

I would also be suspect of the entire undercarriage in general. If your rails are worn down then you start seeing evidence of the "Boss" section of the link will be hitting the flanges on the lower rollers. Aka "Banging the Bosses." Anytime you see excessive wear on any component of a given track system then you should inspect all of the components. If your sprockets are worn this badly then you are most likely going to find other components worn badly as well.