Does anyone have any recommendations for welding and machining the tilt links. I haven't tested exactly what material they are made of, so i can't say offhand what filler metal should be used. Another problem that a machinist will encounter is generally a hard zone at the fusion line interface. Opening the bore a little bit more in the worn part sometimes eliminates the chance of hitting a hard zone. Has anyone done this before?
Most likely mild steel and could have hardened bushings in them. Post the serial number and someone might be able to post the parts diagram.
Standard line boring pracitce is to first machine the bore oversize then weld, it takes the heat-affected zone away from the final bore surface. It also assists by giving a clean uncontaminated surface to weld to. How far oversize would be determined by the diameter of the particular bore. All the material for the lift arms, levers, & links (even the cast ones) is weldable using the same techniques as with mild steel. See if you can find a copy of Caterpillar SEHS8433 online. It gives all the bore sizes, centre-to-centre measurements, etc for everything from the lift arms to the levers & links. I think it's on AVspare but you may have to create an account in order to download it.
If it was mine, I'd probably do it with a welder and die grinder to get it close enough for what it is. The right way to do it is machining it round and either bushing it, or welding back and line bore. Linkage could be done on the "bench" at a machine shop, far cheaper than an on site lineborer around here.
Nige I looked on SIS and found SEHS8433, but at least the version I see only appears to show 950 and higher model numbers. Is there any place on SIS that gives an index of some kind for "Special Instructions"?
I'm really liking the split tension bushings I used for my backhoe swing post. The hole doesn't have to be perfect and because they're split can be pounded in without having to freeze them. They also don't require greasing. Hole can be up to .006" oversize. Would work good with a little welding and a die grinder like Delmer suggested. Final polishing of hole I'd use a flap disc in the die grinder. http://www.connexusa.com/HTML/Spring Bushings.html
Sorry, you need REHS9596 for track loaders. Everything used to be in SEHS8433 but then it got too big & cumbersome so the track loaders got their own Special Instruction. No, sorry. I just download them and have generated quite a library over the years. To search SIS it's quite useful to get into the methodology of how the Cat document writers title their documents.
Not sure that would be easy to do! Often wondered how they think, but not sure they actually do! If there is a book on that I would love to see it! Sometime when I have nothing else to do I will take one of those document number and just change a digit and see what comes up. Just changing one number at the end can take you to a totally different subject! Example changing the REHS9596 to REHS9594 takes you to: CT13 SCR Engine NOx Signal Codes Diagnostic Help{7000} 08/25/2014
Spot on about boring out first then welding - me and the Line Borer had a job on a lumpy great fork truck mast that had egged out pin holes. You could see that the bushes had been moving in the holes and had smeared Non Ferrous whatever Brass, Bronze etc. into the steel pretty much impossible to MIG it. You can be limited on how much you can bore out by the position of the hole etc.