Track Tension

Dcara · May 6, 2009

I need to learn more about this topic. My Komatsu D31 track loader I bought in January (1978 model) does not have any dips on the top of the left track like the right side does (i.e left track is tighter). But then I'm not sure how tight the track should be. How do I figure this out.

The spring on the cylinder that goes to the idler/front wheel is expanded about an inch more on the left side vs.the right which explains why the left track is tighter than the right. There is some type of plate that is just kind of hanging loose on the piston arm to the idler wheel on the left side. On the right side piston arm the plate is bolted to a cap on the end of the spring. In order to get the loose plate into position on the left side I will have to compress the spring a couple inches. How do I do that?

I'll try to get pics this coming weekend.

EddieWalker · May 6, 2009

When I first bought my dozer, I used a straight 2x4 and lay it on top of my tracks. Then I measured down from the board to the low spot in the track. I don't remember what it is supposed to be on my track any more, but know what it looks like to keep it there, give or take a bit.

Have you called the dealer? They should be able to give you that number over the phone. You might also tryhttp://www.heavyequipmentforums.com/Forum/index.php

How far East of Dallas are you?

Eddie

Dcara · May 10, 2009

I live about 20 miles east of Dallas south of Royse City but my D31 is about 35 miles further northeast south of Wolfe City

Below are pics of the spring cap I was talking about. It appears that the reason the left track has no slop/droop is because the track tension spring is further expanded due to a broken bracket which the spring cap is supposed to bolt to. The spring cap on the left side is just sliding loose on the idler wheel piston.
http://i20.photobucket.com/albums/b249/dcara/Springcaploose.jpg

As can be seen in the pic of the right side, the spring cap is bolted to a bracket on the end of a piece of angle iron which is bolted to a support member.
http://i20.photobucket.com/albums/b249/dcara/Springcapbolted.jpg

Here's a full pic of my D31 showing track tension, spring etc.
http://i20.photobucket.com/albums/b249/dcara/Loaderleft.jpg

I think I can weld the broken left side bracket but I have to first compress the spring about 2 inches to get the cap into the proper position.

Anyone have an idea on how I can compress the spring?

Dirthog · May 11, 2009

take a couple of round STEEL pins and put them into the sprocket back the machine up and the spring will compress right back do NOT loosen the grease fitting in the track first though as that will push all the grease out of the adjuster and you will not be able to pull the spring back far enough

Dcara · May 11, 2009

Do you mean to put the pins in the valley of a couple of rear sprocket teeth so that the pins will be between the track and sprocket when I start to back up? Then as I backup to where the pins are in the 3 o'clock position the track will pull the idler wheel piston back into the jack?

I see how that forces the idler wheel piston back into the jack, but what is pushing on the spring to compress it? Also, is it possible to damage the rollers on the track this way?

Thanks
Doug

Dirthog · May 12, 2009

That's right you will not hurt the rollers or anything else the track adjuster pushes against the spring and will force it back. we do this all the time and on a lot bigger machines that that both excavators and dozers. Do NOT try and remove the track on that side that spring could come out of there like a shot. We were trying to get one off a large dozer pressed together in our shop and it got away it finaly stopped after it broke a couple of chains and went through a cement block wall!

Dcara · May 12, 2009

Ok then. What size diameter pins do you recommend? It looks like I need to compress the spring about 1 inch. Will a 1 inch diameter pin compress the spring about an inch? Will just 1 pin do the trick, or should I use 2 or 3 pins?

Dirthog · May 13, 2009

just as long as it is long enough to catch both sides of the rail and not bend doesn't matter what size they are

Dcara · May 16, 2009

great! I'll try it tomorrow. Thanks

Dcara · May 22, 2009

The pin in the sprocket idea works great! I was able to compress the spring enough to fish out the broken bracket shown below. Since there is still free room between the end of it and the end of the cavity it appears that the spring is completely uncompressed now (and always has been) after I took the pins out of the sprocket. The spring and jack assembly appear to be bolted to the track frame via the angle piece that broke where the spring cap bolts to. I was thinking I wanted remove the angle piece to weld the spring cap back on it but am concerned that there mightbe still some compression in the spring. Any thoughts on the best way to weld the angle piece back together?

Also, the 2 bolts holding the spring cap the the broken angle piece are currently frozen in place. They appear to be 15/16 six sided heads. Any suggestions on the some ways I might try to get them off? I was thinking about heating up the bolts with my torch to see if that might loosen them.