Problem with split master link on one track

My Cat 955k has a split master link on the left track. Yesterday I heard a couple of metallic pops while I was pushing some trees, so I stopped to do a walk around. Noticed that one shoe looked on a funny angle, and found that three of the four bolts were gone. Turns out that shoe was on the split master link. I'm a newbie to this type of equipment, and I'm hoping to keep my costs down (like everyone). The bolt holes look to be stripped. Is it realistic to try to repair that link by using a helicoil or drilling out and re-tapping to next larger size? Or, should I remove it and get a new one? Thanks for the great forum. Lots of good info!

You won't be able to either Helicoil (won't stand the stress) or tap it out larger - not enough meat in the links for that, plus they are super hard.

What we do is remove the shoe, pull the link together using as many bolts as will hold up, each one with a pile of washers on it equal to the thickness of the shoe. When the link is pulled up tight you should weld the alligator together both inside and outside on both master links - that's why you left the shoe off temporarily. Don't try to get cute by leaving the shoe on and just welding the outside, it's asking for trouble. Then when it's welded remove the bolts and put the shoe back in place with as many bolts as will hold and also tack-weld the bolt heads to the shoe to stop them backing out. That will keep you running. If you really want to go the whole 9 yards put some good beads of weld between the shoe and the master link as well. Guaranteed not to shift if you do that.

The next time the track has to come off it will be a case of cutting the master link sections with oxy-acetylene and then having new ones pressed on, but at least the "fix" will keep you going until that day comes.

Nige has it right on for a cheap temporary fix. I have seen this method used on D-8H and K dozers and had it last a decent amount of time. It beats buying new parts.

We do it on our D10s so it ought to work on a 955 ..........!!

You may experience trouble getting the bolts to pull the alligator link together due to them being stripped. What ever works best for you is what it will take there, including using some large c-clamps. In the past After the link welding was done, I have just put the "drive bolts"(named from the 8 pounder used to drive them in due to lack of threads) back in place thru the grouser and finished the welding as Nige stated above. Only added thing was to cut/gouge a slot from the outside of the link thru to the bolt. Then weld that back solid. Just a bit of added inssurance. Have done that on rock jobs and it will hold till you either run the track to "destruction" or they are ready for a pin and bushing turn.

Also in order to get it to butt up together correctly you may have to open up the master link and take a grinder to the jaws if there has been any fretting between the two parts of the link due to the bolts being broken. As stated before, do what you have to do to get the link to go together correctly and your weld repair has a much better chance of succeding.

This is great information. Thanks to all of you for your help!!!

Remember to let everyone know how it worked, with photos if possible.

Good news! I was able to "fix" the problem using the suggestions I got from Nige, JDOFMEMI, and riganddig. Initially I tried using a come-along with a large C-clamp, but I couldn't get the teeth aligned between the uppper and lower halves of the split link--so, I took a heavy metal rod, stuck it into holes of one of the other links (just to the left of the master), put a pipe onto it (for extra leverage), then used a come-along to pull the end of the pipe. This did two things. It pulled the two ends of the track closer together, and it also changed their alignment. Once the teeth between upper and lower halves of the link were aligned, I used a scissors jack to push the lower half up into the upper half (did the outboard link first). At that point I ran a bead using 6013 rod and 160 amps. Next I moved the jack so it was pressing up on the inboard link, and then removed the one remaining bolt so I could pull the shoe off. That gave me access to the inboard link so I could weld it. Once both links had an inch or so of welding, I pulled the come-along, rod, pipe, and jack out to give me more room for welding. I finished welding both links, then bolted the shoe back on with the one good bolt hole--then ran a bead on the inboard and outboard contact points. Finished!

I'll be following up with pictures in the next day or two.

Thanks again for all your help!

P.S. I have some other pics from when I replaced the right lift cylinder, and will post those at some point.

Here are some pics showing the problem I was having with aligning the links, along with the solution and the result. Thanks again for all the help!

Yair . . . jgbmo. Good stuff. I find it really interesting when folks are good enough to get back on here with pictures or at least a description as how to a problem was resolved.

Cheers.

Like Scrub says it's nice when people come back and show how the repair worked out. A good set of pictures showing the "temporary repair" should be done IMO . Well done that man ........ :thumbsup :thumbsup