Pins bushing replacement

Whats the best way to remove pressed in type bushings, Working a on a JD410 and has some pressed in bushings, was told to weld a bead around the inside and tap and they will fall out. anyone have expert advise?Will using dry ice to install the new bushings. Thanks.

Welding the inside and letting it cool will shrink the old bushings. I have used dry ice before and it usually doe not work. The bushing heats up and expands back to normal size as soon as you start to install it. Just either use a press to put them back in or I have used a piece of threaded rod to draw them back in.

Usually welding a few beads around the inside will shrink them enough to get them out. If that doesn't work then your next best bet is to use a torch to cut then from end to end on one side and cause them to collapse a little. The last thing to try is pulling them out with a threaded rod, alone and/or with a hydraulic, through hole ram. The problem there is that this typically only works when you've either welded or cut them first.

As far as putting them in goes, dry ice will work just fine. The main thing is to let them set packed in it long enough for them to reach the temp of the ice completely through the bushing, otherwise, as JD seller said, they will expand back too fast to get them all the way in. One way to help the process is to stick them in your freezer overnight before putting them in the dry ice so they don't take as long for the temp to drop enough to get the maximum shrinkage. Even better than dry ice is liquid nitrogen. Over the years I've put in bronze bushings as large as 8 inches in diameter, and steel ones up to 6 inches or so, with it, and used dry ice on items as big as 4 inches in diameter and about 6 inches long with no problems.

Again, the main thing, when using either the dry ice or the nitrogen is to let the bushing cool all the way through so they don't get halfway in and stick there. Good luck.

Depending where they are, I just use a bushing driver and a big hammer. Have also rigged up a porta power and pressed them in and out.

(quoted from post at 21:13:45 12/30/12) Whats the best way to remove pressed in type bushings, Working a on a JD410 and has some pressed in bushings, was told to weld a bead around the inside and tap and they will fall out. anyone have expert advise?Will using dry ice to install the new bushings. Thanks.

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If the bushing is on the small side run a suitable size tap in it then screw the same size bolt in and pull it.
Or run a drill in it just a little smaller than it's OD then you should be able to collapse it with a punch.

Dusty

Welding works well on thin stuff like bearing races. Not so much on thick stuff.

I would take them to my friend that has the machine for it.

You can take the dry ice method a little farther by putting it in a can or bucket of methanol. This can get them down to -60 deg. C. Let them soak for a while. The temp will get down quickly but it takes a little time for the for the full contraction. Just don't pull them out with your hands, use tongs.