D4 7J chain height and bushing spacing

Here's a link to the CAT website for reprints of manuals for old equipment unless someone here has something for sale or check ebay. That is getting pretty old. Seems like you find mostly U series and later these days, but you never know.
http://www.cat.com/cda/layout?m=90800&x=7

Link to link specs on crawler heaven website, you will have to navigate around a bit to get the pitch wear specs for the 6.75" pitch links.
http://www.crawlerheaven.com/tracklinks_chart.htm
I did find a link listed elsewhere that might be your track 6B4645/6B4646 with 3.53" new height and 0.25" allowable wear. The other 6.75" pitch linkss were all 3.66" new.

The Jensales manual is very poor I have one. I'd try and get a cat reprint gotta be better than Jensales.

Thanks for the responses and links. Most helpful.
Chris

Chris - The distance between pin centers is known as track pitch, and on the D4, the pitch is 6.75". To check internal wear, place a long pin, or length of hardwood (3" x 3" is satisfactory) in the top, forward teeth of the sprocket .. and then back the tractor up until the pin or wood is jammed in the track, and pulling the top of the track tight. Lock the brakes at this point.

Then, get out your tape measure and measure across 4 links (5 pins) and write down the reading. New measurement is 26.98" .. 100% worn is 27.46".

There are at least 8 to 10 different track link Part Numbers for the older D4's, from the late 1930's to the 1980's. These links are all slightly different design, as Cat continually improved their undercarriage. The new rail heights ranged from 3.53" to 3.75" on these 8 to 10 links .. and there are also different track shoe bolt sizes, ranging from 1/2" and 9/16" to 5/8".
You need to get the P/N off the links to obtain the correct measurements. It's highly possible the undercarriage has been replaced by later model undercarriage, over the decades, resulting in a possible error, without the link P/N.