Hi,
I am having a problem adjusting the tracks on a 955H Trackloader, S/N 60A10479. I ordered the parts to rebuild the adjuster from Cat but couldn’t find where one of the O-rings went. I first moved the idler as far forward as possible and was able to remove the piston from the Cylinder. The seal was broken in the middle so I thought the new one would fix the problem. I replaced the seal and rings and cleaned everything up. After putting it back together it still would not adjust. This time I removed the yoke from the rod to the idler so I would have more room. This gave me enough room to remove the cylinder and I found where one of the O-rings went, the front of the front pilot. The old one was broken so hope this is the problem but I still have an O-ring that I don’t see where it goes and hate to put it back together unless I replace everything.

If there is an O-ring in the back of the front pilot it looks like I would have to remove the spring assembly, is that the way to get to it?

I also found a problem with the spring, it is broken. Money is really tight now so was hoping to replace it later. Can it be welded? Can I take it apart and reassembly it with it broken?

Any help will be much appreciated,
Gary
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Here is the parts breakdown.....maybe that will help although the picture is not very clear. If you need a better picture I can probably find a similar installation on a different tractor.
Doesn't appear to be an "O" ring at the back of the pilot.
The spring can wait for replacement....welding is not very effective.
Depending on where it is broken it may have an effect on adjuster alignment.

Here's another view....

Thanks, the picture helps, I had this picture but it was even smaller and poor quality.
I think I will put it back together and try it with the new O-ring that is on the front pilot that I missed before and see what happens. I haven't been able to figure out exactly how this works. The cylinder is open on both ends and slides onto the sleeve (long bolt that goes through the spring. When you put the piston into the cylinder it has the seal pointing toward the grease fitting which makes sense. Grease goes in, forces the sleeve to the rear where it contacts the sleeve which should force the cylinder out. There is a little grease at the back of the cylinder, around the sleeve but that could have been there from when the old seal was leaking. With the new seal where would the grease go now. Even though the front O-ring was bad I didn't see any grease coming out? Maybe I hadn't put enough in, it must take a lot to fill the cavity.
Well, I appreciate the help and will give it a try tomorrow.
Gary

Wow! That is really good, this helps a lot!
Thanks again,
Gary

Gary, the groove on the front flange of the cylinder takes a rubber ring and a hard plastic back up ring. The ring in the pilot that fits outside of the cylinder is just to kep dirt out not sealing grease. If the adjuster will not tighten the track now maybe the inside bore of cylinder is bad. I have seen them seal in some places and not in others. Work fine untill you adjust out a bit more then they collapse. Leave spring alone untill you can get a new one.
Later Bob

Here is how the track adjuster works......been wanting to add this to my files:)

new seal where would the grease go now. Even though the front O-ring was bad I didn't see any grease coming out? Maybe I hadn't put enough in, it must take a lot to fill the cavity.
Well, I appreciate the help and will give it a try tomorrow.
Gary

It does take a lot of grease- especially with a hand gun

Bob,
That's what I was afraid of, cylinder worn out. I honed the cylinder today, it wasn't very smooth but I couldn't feel any pits and it didn't appear excessively worn. I cleaned everything better then the first time and made sure the piston was inserted all the way to the rod going through the spring. I noticed on Cat&#8217;s web site (parts store) that the cylinder is a classic (CL) part so it is a lot cheaper so if I do have to eventually replace it they are $103 which I can live with.
This time it worked great so I think it just wasn&#8217;t clean/smooth enough, the hone really cleaned it up. When I inserted the piston you could hear air escaping from the end of the cylinder. I also packed the cylinder with grease before everything went back together so it wouldn&#8217;t take so long to fill with grease.
Thanks again for all the help, it sure made things a lot easier.
Gary

Gary, another thing that can happen to them is since the front pilot is held down by the anchors that are lower than the center of the spring, it gets cocked downwards and bindes on the cylinder. When the anchors get worn the spring humps up. Many times when doing an undercarrage job the cyl locks up in the pilot after collapsing it. That requires taking out the spring and pilot and pulling the cyl out of the pilot with a press.
Later Bob

Bob,
I&#8217;ll keep that in mind, I plan on going through the undercarriage this winter, I&#8217;ll replace the spring and two rollers that are getting bad. The pads are getting pretty worn also so will probably build them back up with grouser material although I can get the pads for about $20 a piece.

It looks like quite a job to get the springs out, looks like I will need to build/buy a press. Is there an easy way to tell if the pins have been turned or is this still an option.?
Gary