Have a bad lower roller. It is within the area with the track guard. It certainly appears the whole guard has to come off to get clearance to get the roller out but I wanted to ask if that is the case? Also, an clue on bolt torque on these? It looks like we will have to waterjet a heavy wrench as I cannot get a big ratchet head in there! I will have to hope the bolts will come loose and I had an older machine where we broke 50% of the bolts which brought more fun in getting them out.
Break the track, lift that side up in the air with the bucket, try biggest air wrench you have, then torch the heads off. Heat cherry red, let cool, try to remove with pipe wrench or weld a nut on the stub, try air wrench again. When installing torque to "effing tight" or alternatively torque to failure, then back off quarter turn. Some of that is actual advice, YMMV I **HATE* undercarriage work anymore....
There is no way to get an air gun, torque multiplier, etc, in there! In the past we had 100% success with just breaking bolts with wrench, then beat the nubs with a BFH, then welded on thick washers, then nuts. They came out pretty easy! I am really hoping not to cross that bridge with this one but...... Why do I need to break track? It looks like at the most, if I have to remove the track guard, I might be able to remove all but two bolts and let it sag down to get clearance? Either way, of course it would be one within the track guard area! If I break bolts on that, the guard will have to come off. Maybe that is where you were headed? The reality of things to come?
Either way you should release as much track tension as possible to allow the track to sag at the bottom when the machine is raised. Also don't rely on the machine hydraulics to hold it in the air while anyone is under it. Crib under the carbody. If you remove the track roller guard on the outsdie of the frame (because it's easier to get to) can you get access to the bolts holding the roller to the track frame on the inside.? If the answer is yes then it may be possible to drop only one rock guard before pulling the roller. If the answer is no then it looks like both rock guards have to come off (that's the way the manual says to do it BTW)
It appears the guard is one single piece? Bolted inside and out. I was originally thinking "no biggy", just take the outside one off, but then realized it is an assembly..... COOL! I can get access to the roller bolts but even on the guard bolts, which are the same size, I can fit a socket, but no go on a ratchet head. I guess I can go to a break over, but I don't think a 3/4" will cut it. I need 1" here.
Did a 324DL full undercarriage last year. Broke 26 bolts holding the rollers, but, I ratcheted most of the guard bolts out easily, but for where the guard was severely bent. Just hot wrenched a notch in those positions. I had been soaking the backside of all the fasteners every day for a week. Ended up torch removing all 28 broken bolts, as no other scenario worked (cherry bolt, cherry frame, inductive heating, welded on nuts, nothing).
LOL! That seems to prove what I have said for years.....panther **** don't work.....heat and shock does. It sounds like I am probably wise to apply the shock and awe right out of the gate. Also sound like I might agree with Nige's advice to chop the head BEFORE they shear off right at the frame. Once all the tension is off the bolt, it should be much easier to pop the threads and get them loose. Quick question, could anyone tell me the actual bolt size? Not the head, but bolt? If I know that, I can determine yield torque as a "do not exceed" value and if they won't let go, I will back off before breaking them. The bolts will take more torque after yield it really sounds like Cat might push these right to the yield point so maybe few options.
pull the guard off use a 3/4 or 1 inch impact they will come out unless they have been in salt water if that dont work use a breaker bar and a pipe bolts are metric I think probably 19mm -3/4 30mm socket I think
Track roller & guide bolts are all M20, grade 10.9. Washers are hardened. Roller bolts 100mm long, guard bolts 40mm long. Recommended torque for the hardware is 340 +/- 40 ft lbs. That's nowhere near yield point for that size of bolt.
If it is only one roller, you can torch cut a section out of each rock guard and then drop the roller straight down. I liked to use a slugging wrench for the roller bolts if I had one to fit. If the bolts are seized tight enough that they will break, there is nothing you can do about it. You have my permission to cuss the guy who installed them without antiseize. If you cut the guard clean enough, you can just weld the sections back in when you have the roller out. Most of the rock guards that were installed on machines in the Northwest were also welded to the track frames at the mating flanges.