The stores "used" to carry ratchet rebuild kits for audible-click torque wrenches, like your golden-oldie Digitork wrench.

And, there used to be a way to send the units out for occasional recalibration.

No, need to remove the pin. That's part of the torque mechanism and not used in replacing the ratcheting mechanism in the head.

The replacement head for this 44478 Digitork ratchet, sold in the 1982- 1983 Sears specialog is not common with any warranted Craftsman ratchet.

A store would already have to "have" an old torque wrench rebuild kit to match it.

Or, the ratchet assembly may be restorable, by substituting in less worn parts from other mechanisms.

There's a little soft steel pin in the middle of that type of ratchet mechanism that is actually a capped hollow, mildsteel tube, that wears down before most of the rest of the ratchet assembly does.

Parts from other ratchet mechanisms can sometimes be found (like Tri-wing or RHFT pins).

Hopefully, the pawl has not broken in half (sintered part).

Some stores, still have old rebuild kit inventory, not electronically tallied, of course.

I would suggest trying your local store's PMT ratchet rebuilder and see if he can find a kit at the store or a close-by one.

Calibration is now done through 3rd party calibration labs.

I can't find the ratchet rebuild kit number for that old torque wrench.

But, I'm pretty sure I've seen it used in some of the old Sears brand, round, diamond-knurled handle pattern, shiny chrome plated ratchets.

It's the 1/2 inch square drive one, with the single bar across the top of it, unlike later Tri-wing selector type ratchet mechanisms.

We also have an internal calibration and repair lab here at Sears. 

searstoolcalibration.com

Most torque wrenches are around $50 for repair and Z-540/ISO 17025, NIST traceable calibrations after repair.

You can send them direct or through one of the local retail stores

cool info

I just visiting the searstoolcalibration website, looked around, and left a note inquiring about HOW their website and services were being promoted internally and on other Sears websites. What a really great SERVICE! So many customers could have been given a place to get free work quotes done on their damaged torque wrenches... had this site's existence been known or made known earlier. Thank you VERY MUCH for the information.

...or you can buy mine for $50 plus shipping.

Where there's a Will, there's a way... Now, is there an electronic one that can link to the shop's Wi-Fi to record the torque setting of the individual fasteners of the machine being serviced, combined, of course, with a remote digital camera image capture and cataloging of the torqueing verification snap-shots AP on the market? Not that people have become overly litigous... Smile... You are being recorded as technician of torqueing!