TD7E lower track rollers

[Grady]

I have a 1978 TD7E that needs some lower track rollers. It has 6" pitch chains. I think the ones from the TD7C will also fit. I could live with some good used ones to last as long as my chains and sprockets will. I found some but still need 4 more. Anyone have any leads?

 

[Garrie Denny]

Have you tried your Part out suppliers as you call them over there ? 78 is getting pretty old for a half decent roller for any machine second hand.

 

[Grady]

You're right about that. I did come across someone who replaced his entire undercarriage and had 6 rollers that were still good so that leaves 4 that I need. I was just hoping someone had a few kicking around that were still good enough to finish off what life there is left in the old chains and sprockets. I think the 6" pitch chains are obsolete and the usual replacement involves updating to 6.5" chains which involves changing sprockets, etc and new chains deserve new rollers so basically a new undercarriage. I just got this machine and would like to put some time on it and make sure it's still got it before sinking too much into it. It smokes a little and the brake pedal hits the floor before it stops but it steers good and runs strong and smooth. I've been changing fluids and filters and a couple of the hard hydraulic lines are leaking and the blade pivot needs help. It hasn't been babied. If I have to buy 4 new ones it won't be the end of the world, I'd just be less concerned about scrapping some used ones. It's old and I only use it on my own property not to make money so it's a low budget affair - until it needs a new undercarriage anyway. If anyone has any advice, I could sure use it. I've had a backhoe for 35 years but the dozer is new to me.

 

[Grady]

I have read about building up the wear surface of old rollers with weld but in the manual it describes cutting down the flanges instead. Anyone tried this method? Is it possible to do without removing the roller? Should I just get new ones?

 

[Scrub Puller]

Yair . . .

Grady

Mate, I was going to mention welding but just assumed you meant the rollers had stuffed bores and wouldn't hold a bearing.

Yes they can be welded no problem. Forty years ago it was standard practice. Rollers were (relatively) expensive back then and provided the bores were good they were sent away for rebuild or, in the bush, it was a wet weather job and we built them up ourselves.

You will need to take them off and if the bearings and seals are good set them up over a cut down oil drum so the bottom half of the roller is immersed in water and just burn a stick and turn them and keep them fairly cool . . . I used to set up two or three and work on them in turn.

I used the largest iron powder stick the rig would run . . . it would be simple these days with a decent wire feed.

On small rollers (and if you do them on the bench without bearings) you can have issues with bore shinkage causing a tight fit for bearings, nothing though that couldn't be rectified with some grinding tape and patience.

In a worst case scenario a 3/8" drill run in and just breaking through onto the bearing bore would be enough to ease the crush.

Try and build up even as possible but don't stress about roundness, half a days work will take off all the high spots.

Back then it was also standard practice to rebuild chains, we used to have them taken to 125% of new with the submerged arc process.

How things change.

Cheers.

 

[Grady]

The bearings are still OK but the flanges are rubbing on the pin boss. What about just grinding or cutting down the flanges like it suggests in the manual? Sounds easier but how much metal is left before they wear through?

 

[Scrub Puller]

Yair . . . .

Grady

The bearings are still OK but the flanges are rubbing on the pin boss.

. . . So what, let the bastards rub, they'll wear their own clearance. I can never see the point in that cutting flanges bull-****e, it sounds like you're going to run it to destruction anyway

Rollers have flanges to keep them on the chains, the assumption is that the chains are worn and snakey so the worn rollers have, in effect, extra deep flanges to help them stay in place.

Cheers.

 

[lantraxco]

The flanges will eventually knock the pins loose as they wear away at the pin bosses in the links, but by then the chains will probably be toast anyway. I would just run them, or you can grind them, or torch them down a bit, just don't let too much heat build up in the shell. They won't wear through, something else will fail first in my opinion.

 

[Grady]

The guy I got it from ran it until the flanges wore the chains almost to the pins but the bottom of the chains are still pretty thick and the sprockets and idlers are very good. I'm just trying to make the chains last as long as the rest of the parts since changing them means changing everything if what I've been told is right that the 6" pitch chain is obsolete and hard to find any old ones that are still any good. I just thought it might be easier to grind or torch some off than building them up with weld although that sounds like a better long term fix. How much flange should I leave on? What do you think is likely to fail before the rollers? Thanks for the help.

 

[Grady]

Scrub Puller, If I build up the rollers with weld, do I roll the hot weld right into the water bath? How long a bead before I quench? Sorry for the amateur questions - I'm a welder by necessity, not by trade.

 

[Scrub Puller]

Yair . . . .

Gotcha Grady.

Just keep turning them as you weld. As a rough guide I try to keep the shaft or caps cool enough to hold your hand on.

Probably doesn't hurt to take any lube plugs out.

Cheers.

 

[Grady]

Thanks, I'll give it a shot.