I've got a Cat 420D It 2002. Today I was digging a ditch. The bucket got hooked into a bit of granite and whipped the entire arm of the hoe when it broke loose. The first damage I saw was the lower pin where the boom and stick meet had slid out a few inches. There was no bolt/cotter pin to keep it in position. I'm guessing it broke earlier and had already fallen out somewhere. I replaced the bolt/cotter pin after resetting the pin. I figured it was fixed but when I raised the boom I noticed that the rod on the upper cylinder of the boom had broken free from the rod head. It was a clean break. I guess it whipped harder than I had thought! Basically I need to buy a new rod with new seals...and install them. How hard is it to replace the rod and seal kit? From some youtube videos it seems do-able. It seems like the best way to do this is on the machine? Now that the rod is broken I will have to remove the pin that holds the head of the rod and then heat up and get the cylinder apart...Seems like it would be best to do it while on the machine? Thanks for any input. Daniel
How bout a picture? can't you weld it in place?
Can't get a pic right now but will try tomorrow. I'm not sure if it can be welded... Where it broke it looks like pot metal and is just before/or right where it changes from shiny stainless rod to cast looking rod head.
It was welded on there before it broke. That's not stainless, it's probably a chrome plating on the steel rod. It's weldable. Call someone.
I'll call a welder buddy and have him look at it. Thanks
Take it to a hydraulic cylinder repair shop. The rod needs to be checked for straightness. The rod eye has to be re-welded in the correct position. There is no room for error when aligning it before welding it back together.
Worth repeating. You're best off buying a new rod
Update: I had a welder come out and look at the broken rod head. He just said "Yep", I've seen these before." I was glad to hear that and gave him the job. He had me hold the rod head in place while he tacked it in a couple places. He then used a combination of a cutting torch and wheel grinders to form a bevel to the end of the rod. Then he backfilled the bevel with beads while grinding and wire brushing before each layer of beads. In the end it looks pretty good. I somehow by myself managed to get the rod head aligned and installed the pin. I tried it out a few minutes yesterday and so far so good. Thanks for the comments and advice. I'll get some before and after pics added to this thread this evening.