350C Undercarriage Overhaul

[amoskevitz]

My 350CB serial number 329326T (which according to a post on this forum puts it as a 1979 model) is in desperate need of major undercarriage work.
The tracks are shot, all of the track pin outer bushings are completely worn through to the inner pin on with only50-80% of the bushing remaining. the idlers flanges are worse than 200% wear and one of them has chunks missing from about 40% of the flange. Presumably the extreme wear on the track has caused extreme wear on the sprocket as well.

parts I definitely need:

• 2x Chain (AT112966)
• 2x sprocket (T129879)
• 2x welded wear strap (T126064)
• 2x bolted wear strap (T20851)
• 2x front idler (AT31141) (and associated parts)
• 1x hydraulic tensioner cylinder

the Hydraulic Tensioner Pistons are aftermarket pistons and were galvanized not chromed and are a bit rusty, with the new chains they will need to be much deeper into the cylinder then before so they may need to be replaced.

parts I might need:

• 2x Hydraulic Tensioner Piston (AT36389)
• bearings/seals

The upper idler and rollers are question marks to me. they are almost certainly very badly worn, but unlike the sprocket and front idler, I assume the consequences of that wear is much lower, (I'm assuming that these guys are not the reason I've thrown or nearly thrown a track 3 times this week). I would like to avoid the expense and work of replacing these, but if they are going to wear through and need to be replaced in 2 years, i would prefer to not have to go through any required disassembly a second time. Another consideration I had was that any irregularities in the wear pattern on the rollers/idler could cause accelerated wear on the new chain, which would be undesirable.

maybes:

• 10x rollers
• 2x upper idler

Finally, are there any other things I should be checking before and during the job that I should be watching for? Red flags that tell me it's not worth doing this?
Are there other "unrelated" things I should do at the same time because it will be easy to get to?
Am I crazy thinking this is a job I can do myself?

[B Town]

If your crawler is functioning as it should, sans undercarriage, it would definitely be worth the time, $ and effort. It will be a transforming and rewarding job. It can all be done with simple hand tools.

If available it would upgrade to the two piece master link.

[amoskevitz]

The part I am most concerned about is removing / inserting the pin, the tech manual tells you to use a D-01030AA which I assume even if I could find i assume would be super expensive (other generic track pin pushers I could find prices on look like 2- 3k+).
removal is probably going to be an oxy torch, but is there any cheaper tools that can be used for the pin insertion?

[B Town]

I’m not sure two piece master or alligator master link is available for the 350. This type of master doesn’t require the master pin to be drive in and out.

[Lavoy]

Find the master pin, burn the center out of each end with a torch, let it cool, and it will drive right out. I have master pins in stock, $25, how much sledgehammer work do you want to do to save $25.
Lavoy

[JWB Contracting]

How we would tackle this repair

- remove all track pads
- cut rails off with a torch
- remove idlers
- remove track frames, easier to remove rollers and extract broken bolts
- remove sprockets
- replace bottom rollers

Reverse order for install

Installing the master pin is not horrible, easier than removing one. We install a slightly undersize pin then click the pin at the back of the tractor and cut a piece of pipe to insert between the rail and final drive to act as a back up. Get the pin started straight and get out your biggest sledge hammer. Some fluid seal or other lubricant will help

We built our own track pin press which gets used a couple times a month. Saves time and effort but if only doing it once in a while it’s not needed. You could also have a mobile mechanic with a pin press come over to push them in.

[boaterri]

I replaced the undercarriage on my 450C much as JWB Contracting suggests except I purchased chains with pads attached and in order to remove the original chains, I collapsed the tensioner using the bucket and pulled the track loop off intact. Beat the master pin in with a sledge hammer.

Good luck, be safe. All the parts are small enough to handle with a come-a-long and rock tooth pick but are heavy enough to really hurt if you drop them on a body part.

Rick

[amoskevitz]

Thanks for all the advice so far.
She's half apart right now. Discovered that old wear strips were so badly worn that there is not inconsequential wear to the frame itself. Should I build up the frame and bring it back to the original dimensions? If so do we know what flavor of steel the frame is made of and therefore what rod/wire/filler I should be using?

[boaterri]

One other thought, you probably want to replace the recoil spring (death spring) and it's associated end caps as well given that everything else is pretty much shot. You will need the special high strength spring compressor bolt to install the spring.

Be safe

[Bw455E]

Thanks for all the advice so far.
She's half apart right now. Discovered that old wear strips were so badly worn that there is not inconsequential wear to the frame itself. Should I build up the frame and bring it back to the original dimensions? If so do we know what flavor of steel the frame is made of and therefore what rod/wire/filler I should be using?

I replaced the whole UC on my machine and both sides idler surfaces needed attention, All I did was weld on some regular mild steel with 7018 rods, I wouldn't think they used any serious hard steel for this application due to all the shock loading. I had 2 busted bolt on wear strips that bolt to the idler and I just made 2 new ones out of plate steel and drilled and tapped them and bolted it all together.

[amoskevitz]

As of yesterday, 12/23, I am again the owner of a functional JD 350C crawler loader. Thanks to everyone here who provided advice, and encouragement. With the new undercarriage she works like a dream, a far cry from where she was before the project.

[boaterri]

Well Done!

Rick

[Labparamour]

That’s great news!
Enjoy your “new” machine