OC4-3d help. Newbe here

[Bigstone]

I bought a OC4-3d  crawler 3 months ago  on a whim.  It runs but after the purchase I noticed the right rear large sprocket was rubbing on the side rail so I haven't run it since. What would be the cause and how difficult is it to repair what is needed?  I have pictures but not sure how to upload them here?

Secondly I don't have any manuals so if you have any recommendations on which manual I should look for I would appreciate you insight here.

Thanks in advance for your comments.

Dave   

[hotratz]

Hello,

Is the sprocket canted over or is the sprocket pretty much perpendicular to the ground?

[Bigstone]

Hotratz sir,

To me it looks like the sprocket is canted.

Dave

[hotratz]

With this information I think I would be compelled to drop the track and start doing some investigation. The sprocket could be loose on the studs OR one of the bearings has an issue OR the center gland nut backed off. Regardless, what ever it is you'll probably be dropping the track to fix it anyway. There are a few pictures in my signature link to my restore pics that might be helpful to understand what I'm talking about.

[Doug424]

One way or the other you'll need to take it apart. If you want to try before you tear it down, use a pry bar between the sprocket and track frame and watch where it moves. If you take the cover off over the studs you can see if it's loose there. If not, the whole sprocket, bull gear is moving on the shaft, meaning bad bearings. If the shaft moves along with everything, you could have a loose axle shaft. They often break loose from the housing. If you do want to test it this way, it's best to jack the machine up to take weight off the sprocket.

[Bigstone]

Hotratz and Doug 424 Sirs,

Thank you for the replies.   Good suggestions here.

One more question.   What is the best way to drop the track? I never been around a track machine before.

thanks again.

Dave

[hotratz]

Don't know if this is the best way but the times I've done it, it goes something like this:

Find the master link pin and roll the crawler so the pin is on top. The pin will have some sort of retainer pin/cotter pin in it that will have to be removed. Then loosen the track adjusting nuts so you have plenty of slop. Now remove the master link pin. At this point you can roll the track off from the top front and back. Now the crawler is sitting on flat track like a train. At this point you can jack up the back of the crawler so the sprocket is not touching anymore. I was able to use a 2 1/2 ton jack to lift mine. Be careful when you drive the master link pin out because the track may want to get away from you at the front idler. You want it off anyway but it could surprise you when you remove the link pin. Reconnecting the link when you're done is a little trickier. You'll need to devise a means to pull the track back together. My first time I used a come-a-long to pull the track ends together, not the best way but I did finally wrestle it back. Since then I made a track tool to do it.

[Bigstone]

Hotratz Sir,

I appreciate the advise.  Now I have to find the connecting link. Did you need to use a torch during the removal process?

The crawler does run but I need to repair the diesel fuel tank first as I have it off now. Then I can move it to where I will did into the repair

Thanks for the tips...

Dave

[hotratz]

No, I did not use a torch for any of it. My link pin was obvious because it was held in place by 1/4" cotter pins. I would not recommend cotter pins be used when it goes back together though. I used 1/4" round stock bend over when it went back together.

[Jack in NB]

On my 3's, I line up the link pin about 9 oclock on the rear sprocket. I can then drive the pin inward without interference, and the teeth on the sprocket keep the track from an uncontrolled departure forward.

I think the 4 track frame and final drive arrangement is similar.

On reassembly, the same positioning and some help from a block and tackle or come-along to pull the links into alignment simplifies the job.

And I've found a spike (4"? 6"?) about right to replace the lock.

[oliverchris]

First of all, remove the sprocket dust shields, and just take a look at the sprocket nuts, the collets (cone washers) and studs to see how tight they are. I expect they are loose. If studs look solid but nuts are loose and collets undamaged, that may be your only problem, you never know. Just tighten them up.
Very few owners tighten the sprockets nuts as often as suggested in the manuals — and they DO come loose.
Start prayin'

But if more than the nuts are loose, then yes, you'll want to take them apart to check for structural damage somewhere in the final drives.

Best of luck.

[Blake Malkamaki]

Chris, no message came through on your last post. Maybe it's just me. Anyone else see Chris's response?

[Jack in NB]

Came through ok for me!

[Will_Faulkner]

Came through for me as well.