I bought a Dresser TD7G that needed new track chains and sprockets. I'm doing the work out back. So far I have removed the old tracks and had the pads cut off. When I got the tracks off I found one floppy roller. I am taking the rock guards off so I can get a good look at all the rollers and decide what to do there. The rock guards are my problem. All those 5/8" bolts threaded up into the track frame. It took me a full day to get one side off. When I started the second side I sheared off two bolt heads. The first I thought was a fluke then the second one made me parinoid about applying alot of torque. I am using a 40" breaker and a 3/4 drive 15/16 socket and lots of PB Blaster. How much torque should a grade 8 5/8" bolt take before I twist the head off ?? And now I am really worried about the longer 1/2" bolts that mount the rollers. Any advise on how to do this will be appreciated. Thanks
First off if you got one side off and only twisted off a couple of bolts you did pretty good, apply heat with a torch and use an impact with the torque set down slightly so that the hammering action will work some on the bolts to jar them loose, sometimes it works, sometimes does nothing to help. I've found to heat and shock cool, impact to chatter them some then the heat and cool again and back and forth, use some penetrating fluid if you want but that never did much for me. I've already torched out a roller to gain access to the top inside of the frame to apply heat on both sides at once to help get bolts out before, just depends on how much patience you have and how much you want to dismantle the machine and which bolts are giving you grief, also it helps to remove the front idler and drive sprocket as well. I've used an air chisel with a hammer attachment to rattle on the head of the bolts some too, that really helps to jar somethings loose some and rattle some rust out, that again is hit and miss but the worst thing you can do is twist the heads off, it goes down hill from there. As for the ones you have and will twist off you have several options, none are really good, first off how good are you with a torch? I've already done this from looking up is to torch the center out of the bolt or if you have enough patience drill the center out and apply heat and easy out them out or if you get tired of that, take the entire frame off the side and flip it over so you can work looking down on it. Same things go for the roller bolts or any other bolts. I've used die grinders to grind the bolt center out before too, with the right cutter it doesn't work too bad. The main thing is to NOT destroy the threads in the frame, life isn't good after you do that, matter of fact it really begins to suck. I've known guys to weld nuts on the twisted off head and some claim that works, I've never had any luck doing that. If you hadn't figured it out yet throw your old bolts away and buy all new when you put it back together, I've got a smaller case dozer and when I did mine, someone before me used soft grade 2 and grade 5 bolts, twisted off almost all of them on the rock guards and rollers and yes I torched them all out from looking up, something I'd never do again, next time I'd take the frame off the side and flip it over for that. Grade 8 bolts are hard to drill and get in the center, also you'll need to use a tap to clean up the holes for the new bolts, I've never done a dresser before but I'd guess they are like most others and the threads are tapped into the frame housing. As for the torque specs, first make sure your dealing with grade 8 bolts and then find a service manual to look up the torque specs in that, off the top of my head I can't remember for sure and all my manuals are in the shop. Are you sure the rollers are only held on with half inch bolts? I'd think the rollers and track guards would be the same 5/8 inch. When you get done doing the job you can look back and say, now I see why the track shops charge so much for labor. If your running rock guards and already have one roller shot I'd opt for replacing them all before putting the rock guards back on, I use anti seeze on the threads of all the new bolts when I put them back together, they don't recommend that but it makes life easier to take apart the next go around. I've in the past taken all rollers off both sides and used the best used one's on one side and put all new on the other and put it back together that way to get some more wear out of the rollers before. I've rebuilt them myself before but its quite a job to do and looking back wasn't worth the time I invested in doing it but it did extend the undercarriage a lot of hours. I"m curious as to what others say about how to get bolts out, since I've got a roller out on one of my dozes with rock guards on and was hoping someone had the magic cure, I've been putting off doing it for just the same reason your having trouble now, its not a fun job and after you do about a half dozen undercarriages it doesn't get any more pleasurable either, matter of fact you dread it all the more.
U/C is hardly ever a job for the impatient or faint of heart. Iv'e done everything from easy outs,to burning broken bolts out to sectioning in new sections and drilling and tapping new holes For any undercarriage job,send it to the pros...every time Get a quote and hold them to it The apprentices will do most of the job,but the high dollar guy like me will do the breaking of bolts and dealing of broken bits. ....unless you're a sick SOB and want to do this on your own time....lol
Thanks for taking the time to help me out. I feel better knowing that it is normal to be tough going. I never thought of burning out the broken bolts. I am not good enough with a torch but I can get it done by someone who is. My track frame is shaped like an I beam so I can see the bolt ends, The tapped holes are not blind they pass through the lower flange. Can't get a drill in there inline with the bolt axis but could torch it from the top. I can see the tops of the roller bolts and they are only 1/2". I do have the sprockets off. Thought that would be the hardest part but it turned out to be relitively easy. This is going to be a machine for use around my place and woods, not a day in day out construction machine. I considered tack welding the rock guard on where I broke the two bolts in hopes I won't need to remove them again for a long time. What do you think ?? Thanks again
I wouldn't weld any track guards on ever but thats me, I'd at least try to get some of them back in depending on which ones that are broke and where they are located I've even left some bolts out before I'd weld the rock guards on. I figured thats how the frame was made, its pretty standard that way. The biggest thing is to attempt to rattle them loose, with either a air chisel with a dead blow or hammer head in it and hammer directly on the heads or else set down the impact and let that chatter on it awhile and apply heat off and on to the rest of the bolts you don't have off yet. There are people who have the skills to torch out the bolt centers in nothing flat and make it look very easy, they'd have it done in less time than I've spent typing this up and you'd be back putting bolts in again. I spent considerable time to do the job but I did get it done without ruining any or very many threads, the hardest part was I didn't want to take the whole frame off and did it by laying under the machine torching up, it would have taken maybe a few hours to do the entire job had I flipped the frame over, again hind sight is 20/20. After that machine I've virtually never broken off a bolt on any I've taken apart, I learned what a headache it is to get them out after I twist them off so I work pretty hard and exhaust all other options first before resorting to twisting them off and torching them out or drilling them out. If your luckier than I am maybe you'll never have to take the guards off again for the few hours you put on the machine, but I'm not that lucky, I'd weld them on and two weeks later a roller would go out and I'd have to cut them back off to replace the shot roller, but thats your call. If you would ruin the threads beyond repair you could put a smaller bolt in and put a nut on the top side and do it that way, actually I've got a machine of mine that's what someone before me did, but I opted to weld the hole shut and retap the threads back in again, not a great way to go but worked just fine for what it holds.
Your thoughts on why not to weld the rock guards on makes sense. It was raining yesterday so I worked on the track adjusters in the garage. The old adjuster had a piston seal and a wiper seal at the end of the tube. My seal kit has those two seals plus it has two split ring gaskets of square cross section. What do I do with these split rings?? They are no shown in the pasts manual. thanks
Thats a different setup than what I'm used to so I"m not going to be much help to you there, as for the adjusters I've been around, most times the shaft has rust pitting on it and the seals won't seal properly and I end up buying the whole deal new for the adjuster, I use aftermarket parts and they seem to last about as long as factory replacement parts. I've rebuilt several over the years only to find they are again leaking in a couple of months. I've had new pistons put in several and resealed them that way but by the time I'm done I've got just as much in it as aftermarket and they usually still end up leaking, a lot of times the bore inside has rust pitting in it as well and causes it to leak that way. Before doing much make sure the shaft and inside bore are rust and pit free, and also free from damage of any kind or they'll leak again and cause the track to get slack in it daily.
I know for smaller cylinders that stainless steel inserts are available to give a new cylinder bore surface. From what i have been told, they are generally very successful. I don't know if these sleeves are available in these sizes, but might be a thought when you are rebuilding them.