Track adjuster

[Rincon]

Hello all. Haven't been on here looking for advice lately. But do check in from time to time. JD 450c 1976. Replacing under carriage this month. Have my chains both sprockets and idler assemblies. Whew 6400$ with shipping. My grousers /pads are still 65 percent. 1 1/4". Original Front idlers are real bad. All rollers seem to be good for several years to come. I rebuilt the right final drive back in 18. My question is, I am going to replace seals on track adjuster as well. No seal leaks. Cheapest repair of everything. Is it straight forward ? Or not ? Thanks.

[amoskevitz]

I have had the "joy" of working on my track adjusters 3 times since I picked up my 350C 8 years ago (once when I first got it to replace rusted out pistons, once when the port cylinder split apart from wear, and once when I rebuilt the undercarriage last year). If the piston and cylinder are in good shape and moving freely it is not a difficult job. (even if they are not moving freely a little elbow grease and a couple of giant pipe wrenches combined with a bit of grease gun action got mine free, but it sounds like yours are moving currently)
A few things to watch out for are:

• The OD of the outer seal on the replacement cylinders was different then the OD of the original, the 450C appears to have multiple part numbers listed for that seal as well so be sure you have the right one (the end of the cylinder has a chamfer so it can fit enough to seem like it is ok, but it fall right out at the slightest whim). I ended up getting one from McMaster Carr (mine was pn 1504N25 but you would want to measure yours).
• Your rebuilt undercarriage will mean the piston will push way deeper into the cylinder then it has in a long time, there is likely buildup or corrosion on one or both sides that needs to be taken care of before they will be ok doing that.
• Don't forget to put the outer seal onto the piston before you insert it into the cylinder, it does not fit over the weld bead on the piston.
• When inserting the piston into the cylinder it is easy fold back the wiper edge of the inner seal, despite how solid it seems when attaching it to the piston. I did that my first time and luckily messed something else up and discovered that when I disassembled it, every time since then it has been easily avoided now that I know it can happen
• Check the thickness of the bottom side of the cylinder wall vs the top, my adjusters both eventually wore so thin from dirt sitting on the track frame that the casting split down the bottom. If you find a substantial difference, even if you don't decide to replace them now, you will know what may be in your future.
• Finally, remember you will have substantially less space to work with after the undercarriage rebuild, it took me two tries to get my adjusters in (had to get the pistons a lot deeper than they wanted to go after my first cleanup)

Good luck with the rebuild, I certainly enjoyed mine. The she moves like a dream now.

[Rincon]

Thanks for the in put. I replaced seals on the adjuster pistons no problem. However, my left side piston pipe was broken/ sheared right at the spring plate. Installed that with vertical press. I welded a sleeve inside the pipe to extend back in to the pipe that was sheared off. About 1 1/2" of sleeve. Right side was frozen rusted into the spring plate. Was able to use my portable power ram to insert the seal on to the piston. Both sides have some wear but nothing major. Guess they didn't design this to well for years of use. Left side complete. Right side finish up this weekend.