Thread locker?

Crackerjack222 · Mar 3, 2021

I have a D5G that has dropped the right front lower track roller. I put it back on With new bolts after running a tap in the holes, but noticed that at least 2 of the four bolts have partially stripped threads. I see that some one had tried to weld it on, but that did not hold. After about 45 minutes of operating one of the bolts is hanging loose after backing out about 5 threads.
So I don’t want to have to drill and re-tap the holes to a larger size. Is there a thread locker that might help lock the bolts in place? JB Weld? Any suggestions?
How dangerous is it to operate without that roller?

heymccall · Mar 3, 2021

If the holes are deeper or thru, use a longer bolt.
As for thread repair without tapping or helicoil

Just take note that torque specs will be lower. 3/4 bolt...648 in/lbs...or 54ft/lbs

Maybe a combination of both?

epirbalex · Mar 3, 2021

Crackerjack222 said:
I have a D5G that has dropped the right front lower track roller. I put it back on With new bolts after running a tap in the holes, but noticed that at least 2 of the four bolts have partially stripped threads. I see that some one had tried to weld it on, but that did not hold. After about 45 minutes of operating one of the bolts is hanging loose after backing out about 5 threads.
So I don’t want to have to drill and re-tap the holes to a larger size. Is there a thread locker that might help lock the bolts in place? JB Weld? Any suggestions?
How dangerous is it to operate without that roller?

Puts more weight on the idler with a roller missing , you need to retap . Real hassel if you have not got the room . You may have to make extentions for you drills and tap .

Nige · Mar 3, 2021

IMO even that Loctite repair product posted above by HMC likely won't hold if the threads are as badly worn as you indicate. Note the max torque figures it quotes are in inch pounds, not foot pounds. So for a 3/4 bolt the max torque is only just over 50 ft lbs. The specified torque for those bolts is 200 ft lbs in round numbers.

What about thread inserts such as Helicoil (other brands are available) to be able to use the original size bolts if the holes are into the track frame.? There ought to be plenty of meat to work with.

That or cut a window in the track frame and tack weld a nut on the inside, then refit the window. it would require longer than standard bolts though.

As others have said, don't operate without that roller. It will probably take out the front idler in short order.

JD955SC · Mar 3, 2021

Caterpillar makes an excellent thread repair insert and that is what I would use provided you have the meat around the bolts to drill over size

92U 3406 · Mar 3, 2021

Those Cat thread inserts are the cat's ass. That's how I'd go about it if they could be used.

Welder Dave · Mar 3, 2021

I was told to use blue lock tight on roller bolts. Keeps them from loosening and also from rusting.

Tyler d4c · Mar 3, 2021

Mcmaster carr get the size you need best thread repair ive found there moreless the same as the cat ones

DB2 · Mar 3, 2021

I’ve used that style with good results.

JLarson · Mar 4, 2021

I'm a big fan of the key lock style inserts with a healthy side of loctite for good measure in such heavy service applications. Never had an issue with that as a repair unless someone came along later and chowdered up the threads in the insert later lol.

Orest Anhel · Mar 4, 2021

Pinned inserts like Keenserts are stronger and more durable than helicopters coils. Check out Locknstitch

DMiller · Mar 4, 2021

Have used both Keencerts and Helicoils where do prefer Keencerts in high stress areas.

Tugger2 · Mar 4, 2021

Its amazing what modern technology has provided for repairs like that . Back in my days at the Cat dealer the cure for stripped threads and loose rollers was a whole new pocket machined from a block of steel . On front rollers we normally cut both sides out ,tacked new ones in with a dummy roller shaft for line up and welded them in.This was done on D8 and D9 I believe this solution was right from Cat.

Crackerjack222 · Mar 4, 2021

I don’t have any way to drill out the existing holes to put in something like a Helicoil. There is not enough room between the track and the underside of the frame rail for a drill. I have an angle adapter for a drill but it is only 1/4” chuck and I sure don’t want to break the track to get more room.
So I have ordered a stick of Locktite 268 and will try that.

DMiller · Mar 4, 2021

IIRC back a few dozens years getting machined inserts from a Cat supplier we installed with Cat two part epoxy cups on stripped out bolt boles on the articulated loaders at the quarry, up sized the threaded holt to either one or two sizes up bolt threads drilled, tapped and installed this insert, peened along edge of insert after install and then had to await a few hours epoxy cure. Never saw one of those come loose.

Dave Neubert · Mar 4, 2021

break the track drill it put the inserts in or you will never get it to hold

DB2 · Mar 4, 2021

Can it be welded in place until a proper repair can be completed?

Nige · Mar 4, 2021

Dave Neubert said:
break the track drill it put the inserts in or you will never get it to hold

If it was mine I'd go one stage further. Break the track then track frame off (it only weighs 900 pounds) and turned upside down so that the hole drilling for tapping could be done using a mag-base drill working off the flat surface on the bottom of the track frame.

This is a one-shot only job. Do it once, and do it right, and it should never come back to trouble you again. Do it half-assed and you would probably be deeper in the sh1t than you are right now. My opinion (*other opinions may be available)

John C. · Mar 4, 2021

Done plenty of helicoils for bottom rollers. The drill bit isn't too big and you can do it with a regular 1/2" drill motor. It isn't easy but it can be done. If you go with the Keenserts, the bolt hole has to be drilled to the next larger bolt and a mag drill is pretty much required. You also have to be concerned that there is enough meat left around the hole to hold the insert from breaking out. You should also be concerned that the rest of the rollers might be loose. This type of job sucks and there is no way to make it quick or easy. Either jack the machine way up in the air and crawl under the track frame or pull the track frame and work on it standing up. That machine as I recall only has the bolts for the equalizer and the cap for the pivot shaft holding the track frame to the machine.

Coaldust · Mar 4, 2021

Oh’ the woes of heavy iron.

Nobody has mentioned welding straps between the bolt heads so they don’t come loose in the first place. Is that still common practice?

No shortage of stripped threads and broken dreams under that Dee Five Gee.

Hire me and I’ll fix er’ up like it’s supposed to be.

On the job, when I roll up.

With Service Truck eighty-seven, ready to tow up!

Clear a spot, eighty-seven coming through.

Rolling heavy With a Six Point Two!

Nothing left to say. Time to stop talking about it and to be about it. Pidder-padder, let’s get at er’. Time to busta move and bust some track. Knowwhatimsayin?

Thread locker?

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