450C Day 3: Blowing oil out front grill and cracked idler

[Goober]

Day3 with my new 450C dozer: It just keeps getting better and better. First I find out that my new dozer has more UC wear than I thought, now I take it for a little spin in the field to do some practice cuts and when I bring it in to park I find the cylinder shield on the 6-way is covered in egine oil and so is the grill. Front right idler also has a 5 inch crack from the outer flange inwards towards the axle that I hadn't seen before. Someone tried to weld it, but we all know what happens when you try to weld a large piece of cast iron, just makes the crack bigger. I can see the dollar signs now. What kind of catastrophe can happen with a cracked idler? Is it something I can just run with until it really breaks?

And not entirely unexpected, I spent 10 minutes digging some boulders out of the road and two hoses on the backhoe sprung leaks. My Parker crimper from EBay is on it's way though, so I was at least prepared for that. Once I see what die rings it comes with I'll get myself the hoses and fittings and go to town on every hose on the machine - they all need replacing, except for 2 new Aeroquip hoses that the PO replaced so he could sell it. Looks like they are all 1/4, 3/8, mostly 1/2 and a few 3/4" - anything bigger than that?

I'm hoping the engine oil is just some rotted hoses - the thing was sitting in the baking Sierra foothill sun for 5 years unattended, so I'm still hopeful. Cracked idler - not so much.

Anybody in NorCal know of a good place to get undercarriage parts? Local JD dealer (1 hour away) is Pape machinery in Sacramento, but there are a bunch of machinery dealers in Yuba city. I'm probably looking at bottom rollers, idlers, sprockets, heck 1 might as well get new chains as well or at least have the P&B done.

Not a good day.

[DBCSteve]

I got my undercarriage parts at the Berco dealer in Woodland -- Industrial Tractor Parts on Pioneer Ave. Got two sprockets and all-new assembled tracks. Excellent prices, and interestingly they were recommended by the guy at the Pape Machinery parts counter in Sacramento.

If you are interested I can send contact info for a great independent mechanic who is an expert on older 350s and 450s. He lives just south of Placerville and is a retired JD mechanic. He's helped me several times.

Steve

[jthornton]

I weld cast iron all the time, you have to use the right rod and go real slow and peen the weld right after welding an inch to relieve the stresses. Any welding shop should have the right rods IIRC they cost me about $1 each last time I bought some.

JT

[DBCSteve]

Probably not engine oil. There is a hydraulic spin-off filter behind the grill and in front of the radiator. That's the transmission case oil filter, shown on page 55-4 in manual TM-1102. You might just have a bad hose. You should also check the transmission oil fill level (under the seat).

Steve

[shinnery]

I think I would try to stop the crack by drilling a hole at the end of the crack first.
Bryce

[Lavoy]

Idler is cast steel, not cast iron, they weld very well. Vee it out, weld it back shut.
Lavoy

[Goober]

This is good news - 7018 stick weld? TIG? MIG? What's the recommended process? Preheat?

Just got quoted ~$5K for a completely new Berco undercarriage, although it looks like I can get away with a P&B turn plus some bottom rollers and get a good bit of life out of it still. Anyone weld up additional material on things like idlers and rollers and then turn them back to spec? I've got a 15" Monarch lathe that could swing those idlers.

Idler is cast steel, not cast iron, they weld very well. Vee it out, weld it back shut.
Lavoy

[Tigerhaze]

Goober, there is a number of threads on this board about welding cast steel- these were the better of he ones I could easily find:

http://www.jdcrawlers.com/messageboard/ ... cast+steel

http://www.jdcrawlers.com/messageboard/ ... cast+steel

http://www.jdcrawlers.com/messageboard/ ... cast+steel

[jtrichard]

This is good news - 7018 stick weld? TIG? MIG? What's the recommended process? Preheat?

Just got quoted ~$5K for a completely new Berco undercarriage, although it looks like I can get away with a P&B turn plus some bottom rollers and get a good bit of life out of it still. Anyone weld up additional material on things like idlers and rollers and then turn them back to spec? I've got a 15" Monarch lathe that could swing those idlers.

Idler is cast steel, not cast iron, they weld very well. Vee it out, weld it back shut.
Lavoy

in you other post i seen that your pins and bushings look like the have been turned already

[Goober]

in you other post i seen that your pins and bushings look like the have been turned already

Indeed - both chains have had at least one P&B turn done - left chain has more wear than right - left may have had 2 turns - I am not yet an expert on these things but I can feel 3 distinct wear flats on each left bushing but only 2 on each right.

[jtrichard]

As far as i know they only turn once never heard of more than once

[Goober]

Guy at the Berco dealer who does the P&B turns says they do 1/2 and 1/4 P&B turns on dry chains. First turn: rotate the bushing and pin 180 degrees (1/2 rotation). Next turn: rotate pin and bushing 90 degrees (1/4 turn). Third and last turn (if a chain ever makes it this far) is another 180 degrees (1/2 turn). Based on this knowledge, I'd say one of my chains has been turned once, the other one tuned twice.

[Stan Disbrow]

Hi,

I have not seen more than one turn either. By the time you would need it again, everything is pretty well done.....

Stan

[Lavoy]

Not to dispute the Berco guy, but I highly doubt it, I have never heard of it, especially on rails the size of a 450. There is not enough new wear surface exposed with a quarter turn to do any good at all. Plus, once the pins and bushings have been turned, there is enough stretch in the links that it is unlikely that there would be enough tension to hold the pins and bushings in the tracks. This is why new replacement pins and bushings are oversized to compensate for the stretch.
In the old days, you would turn them once, then rebush, and maybe turn them again.
Lavoy

[Goober]

Well, spent the last 2 1/2 days doing my first-ever wrenching on a dozer. First order of business was how the heck do you block up a 14,000lb machine, 17,000lb with the backhoe. Spent some time thinking about it and decided to park it over the small pit with my lift in it and block up the front and rear a bit.

Rear blocking - 4x12 and 6x10s, plus 4x4 cross pieces to stabilize the load:


Front jack stand:


The rear blocking was fine, the jack stand up front gave me the willies, even though it's a 6 ton jack stand. I was looking for some way to keep the front of the machine elevated, but still allow me to get underneath to remove the inner rock guards and roller bolts. After trying to crawl around and under past the 6 way blade with that jack stand in my way I decided to find a better method. I ended up lifting the front end with the blade and setting it down on some 4x8 blocking, then raising the 6-way all the way to the top and blocking it up with 4x4s.



The 4x8 made it difficult to get a creeper underneath and the pit, although it gave me clearance, had all that stuff in it that made it difficult to find good position to wrench from, so in the future I'll just drive the dozer up on some 8x12s on a flat concrete pad and raise and block the blade and use the creeper to get underneath.

Here's a pic of me underneath with the air gun pulling the roller bolts:



All except one came out without a problem using the 1/2 inch gun, although it just barely had enough power to pull those roller bolts (~500ft/lbs). It wouldn't touch the larger and rustier rock guard cross carriage bolts or the bolts that attach the rock guards to the track frames. I already have a more powerful 1/2 inch air gun on order, and wondering if I should get a 3/4" air gun and some sockets for working on the dozer. For all the 15/16" bolts I had to use a 3/4" breaker with a 4' cheater bar. And 4 of the rock guard bolts are in such a place that you can't get a 3/4" socket in there, barely even a 1/2" drive socket, so I ended up using the 1/2" drive socket, plus a 3" extension, a 1/2" ratchet with only 2/3 of the drive engaged with the extension and 5 feet of cheater to get those 4 bolts out, being really careful to align everything and wedge my foot up under the ratchet head to prevent it from camming out on the bolt heads. I really need a set of 3/4"-1" box wrenches I think - that would've made those 4 bolts easy.




The rear rock guard bolts presented a problem as well, they were pretty rounded and mushroomed being exposed out there on the end, so I torched them to heat them up and quenched them to hopefully break the rust, then heated them up again and pounded my socket upwards onto the bolt heads - both came out without issue. I was also careful with all the rock guard bolts, if they didn't yield easily to a 4' cheater bar I heated them up and quenched them with water before trying again - I really didn't want to have those break off in the track frames, and it must've worked, I didn't break a single one off in the frame.

Oh, and a testament to using impact-rated accessories:



So, after all 4 rock guards and all the roller bolts were out it was a simple matter of hitting each roller a few times with a 3lb sledge to break it free from the track frame, rolling it to the middle of the dozer where I had the most track to track-frame clearance and tipping the rollers out off the bottom track. Here they are lined up:

Left track, front to back:



Right track, back to front:



Any of those rollers salvageable? I'm still trying to figure out where that extra piece of metal on the left rear roller came from:



It wore a circular hole all the way through the rock guard (bad pic, I know, look carefully in the lower right cutout):



Also check out the wear on the crossbolts and cross bolt tubes:




Right rock guards look pretty good, still wear on the front and back crossbolts:



Oh, and here is a pic of my broken track-adjuster:



I'm getting all new bolts and crossbolt tubes, going to have to drill and tap out that one broken roller bolt, then chase all the threads in the track frame - anybody know those thread sizes off the top? Rock guard bolts are fine pitch, roller bolts are coarse, as are the crossbolts. Many of the roller bolts were bent, and every one of the crossbolts and tubes were bent at least a bit and partially worn through, 50% of the lock washers disintegrated upon removal. I twisted off 3 of the crossbolts which worried me at first until I figured out they were just big carriage bolts. Clamp the crossbolts on the inside of the frame to keep them from rounding out the square holes in the inside rock guard. First one that started spinning I didn't notice in time and will have to weld and square up that hole so it will hold the carriage bolt head. Is it fine to use generic grade-8 fasteners here, or should I go with JD parts to keep the mystery alive?

It's 100 degrees here today, I'm exhausted, sweaty and filthy, but I have all the rollers off, and only one broken bolt issue to deal with. Pretty good outcome all in all. Next it's on the splitting the tracks so I can fix the left track adjuster and remove the right idler and weld up that nasty crack.

Happy labor day!

-Niall

P.S.: I am starting to think that based on the amount of work required to remove all this stuff that maybe I should replace everything while I have it apart, but I really want to get the last few hundred hours out of this undercarriage so my wife doesn't think I'm crazy for replacing parts that look like they could work - she is the one that bought the dozer for me after all:



She was getting a bit jealous that I was spending so much time with the dozer, so she came and tried to distract me (and actually helped do final removal of the rollers from the track).