420C - Been in the family forever but has seen better days

[kc135cruechief]

Hello all,

I inherited a 420 crawler about 16 years ago when I was in high school. It was bought new by my grandfather and I have many childhood memories of it. I went in the military about 14 years ago and the crawler was left tucked away in the corner of an old barn on my parent's farm in Ohio. About 8 years after that I discovered that my uncle had apparently borrowed it shortly after I went in the service and it ended up spending many years in the woods behind his trailer. I was disgusted when I found it and used my dad's 4x4 tractor to drag it back to one of the barns. The time in the woods did not do it good! I pulled the engine out a few years ago and rebuilt it when I was stationed in Georgia. It took .125 overbore rebuild kit to get all the pitting off the cylinder walls; the .090 cut didn't get it all. I got the dozer running again but both steering clutches were locked up. I pulled the final drives out a a year or two ago and never really go around to rebuilding them until I recently found out my parents are selling the farm. The dozer needed to me moved, so thanks to Lavoy I got all the parts and technical advice I needed to rebuild the clutches. I just installed them last week and the engine purrs like a kitten and the clutches work great. My Grandfather (now in his 90's) was grinning ear-to-ear when he saw it moving under it's own power again. That alone made every dime and hour I put into it worthwile! I brought the crawler to my current duty station which is in Goldsboro NC. This thing has a lot of sentimental value and will be a restoration project for me and my two sons. This thing will never see hard use again, but I do want to get it back in good condition. My intent behind this post is to get some advice for the drivetrain. The 8 years it spent in the woods nearly destroyed the tracks and roller frame. I've measured the track wear and it is over 100%. The chain seems significantly worn to me and I'm not sure if they would be worth re-bushing. I know track parts are pretty scarse and I don't have and ton of money to put into a machine that I really have no need for other a family project. That said, I don't plan to ever sell it and hopefully my kids will someday inherit it. I'm attempting to attach some pictures of the sprockets, chain and tracks and would love to hear some advice about what I should do. Please let me know what yall think. FYI, I do have the blade for it but it was left in Ohio due to towing weight issues. I believe it is a very early 56 model as the SN is 80,101.

[kc135cruechief]

Just fixed the photos above so ignore this

[OneWelder]

The sprocket wear would indicate getting close to or at a pin and bushing service ( turn or change The rest does not appear that bad - links still show good heighth , and are flat . Rollers are not hitting pin bosses . Grousers have some heighth and are not rounded
I am assuming your 100# wear measurement was the wear on pins and bushings

[kc135cruechief]

Yes, my 100% wear was on the pins and bushings. The distance between links was just over 23.5 inches.

[Lavoy]

I think your links look fine for rebushing, I would not replace the rails.
Lavoy

[jdman]

If Your Not Going To Use It Much, Just Restore The Way It Is.. You Have Alot Of Adjustment Left In The Front Idier Screws... Pins And Bushings And Labor = Big $$$$$$$$

Jeff

[Paul Buhler]

Hi: I've been researching getting my 420 re-pinned and bushed. I can not find any after market parts which makes this an expensive project.

My rails, sprockets and front rolls (idlers) look similar to yours, and my center to center pin distance is 23 1/2" and I have about as much adjustment as you show.

That being said, I tightened the tracks to specs and run it carefully ( I'm most concerned about the "snake" in the chains). I worked on getting the track adjusters working easily and fully so that if I throw a track, it will go on more easily. Since I've done this , I've put some hard hours on the machine pushing dirt, re-grading, road building, and skidding logs. The tracks have not come off, and I've been able to do the work needed. I'm careful on side hills, in rocky soils, and I stay out of sow holes. I listen and feel for when the tracks might be tensioning unreasonably, and take corrective action avoiding a thrown track.

I'll keep looking for an upgrade solution, but in the meantime, so far so good. Good luck running yours. Paul

[H-D]

It was a while back, but a member was in the right place at the right time to buy pair of 'rubber tracks' from an importer of oriental tracked equipment. They had been on an excavator that a city bought with the condition that it be upgraded to 'steel tracks'. The tracks were very cheap & the sprockets & adaption machining/welding was reasonable. You might try a search regarding 420 rubber tracks. It's an edifying read, if nothing else.

[kc135cruechief]

Thanks everyone for all the responses. I know I could get by without rebushing but somehow knowing that I'm at 100% wear makes me pretty determined to do something. Both upper idlers are either froze up or has so much slop I amazed it still turns. I haven't checked the lower rollers but I can only imagine they are as wore out as what the tracks are.

I thoroughly read the post regarding rubber tracks on a 420. It looked very straight forward but I don't have a buddy with a machine shop willing to do free work for me. For a restoration standpoint I think I'd like to stay stock since that is the way I always remembered it.

Ebay has some interesting 420 parts every now and then but I don't know if I'd trust someone else's opinion on wear. From what I gather parts are getting scarse so maybe that is the way to go.

I'm guessing I'll be breaking off alot of bolts when I start to pull the undercarriage apart. I will heat them up with torches, but some of them are pretty rough. The track tensioner bolts are well seized so I'll try working them first. In my mind i already figured they would have to be cut off and re-made from threaded rod.

Thanks again everyone for the help!

[Paul Buhler]

I'm guessing I'll be breaking off alot of bolts when I start to pull the undercarriage apart. I will heat them up with torches, but some of them are pretty rough. The track tensioner bolts are well seized so I'll try working them first. In my mind i already figured they would have to be cut off and re-made from threaded rod.

Give the adjusters a fair chance to come around. It sounds like you know the process; heat,jism,torque, swear, repeat. The rod has/had a hardened thread, that cleaned up pretty well for me. I did have to buy some yardsale 1 1/2" wrenches that I sacrificed to the cause to get the inside rear nuts free. If you're planning on doing a disassembly, having the track frames out in the open will give you better access, and a bit less swearing. Now if you can buy some spring and bolt assemblies for a fair price, you may be on to a short cut. Good luck. Paul