D4 6U track questions discussion

The bolt holes will be larger on new rails, I dont know what Cat offers now but Berco has sealed rails, not lubed, that work well, not sure on track shoes though. It's not really worth turning pins and bushings on a small crawler, it's up to you, and depends on rail height also.

yeah i understand and agree. do you know the berco part numbers? if the bolt pattern matches i could always have the pads drilled for larger bolts but all of this adds expense. does berco rails fit the old sprocket dimensions?
Thanks

Yes Berco will fit the older sprocket, you can check with Mike Zimmerman he sells Berco I believe and has allot of old D4 knowledge. 573-378-7210

Thank you very much

is Mike Zimmerman a member on this board?

[quote="bursitis"]i have a D4 6U of 1953 vintage. it is time to turn the pins and bushings so i called my local Cat dealer to see if they would do the job. they told me that it would be more economical to just replace the chains. this is where it gets interesting and i have a few questions.
1. my sprockets are fine and don't need replaced
2.my rails are the 6B4645 so they are the early type and the pads have 1/2 inch holes instead of 9/16 or 5/8
3. my rails are in spec for a turn and the grousers are fine and on the 6U are 13 inch. can't be any wider on the 6U.

so really all i need is a turn and reinstall but i am not against updating to a modern track group,but i think the new track assy will have bigger bushing diameter and might not have the proper shoe width either but unsure. question is will the newer style track chains work with my sprokets? is there an aftermarket that closer matches my original dimensions?[/quote]
If Rails are in spec I would look at Getting a track shop to fit new pins and bushes into your Rails, either genuine or after market.

is Mike Zimmerman a member on this board?

Cat lists the track with small bushings, sealed (4K3918 regular bushings) 6.75" pitch, 1/2" holes as Link assembly 4K7128 which is a 36 link version, remove sections as needed.