1956 D4 Cat (Series 12A Traxcavator), dry brake sticks and pops

Welcome to the place with all of the answers most of the time.😉 A dozer or ag tractor it is relatively 🤞 easy to replace the brakes. All the loader apparatuses does make it harder. How much harder I don't know. Relative is a relative term, rusted broken bolts all make a difference.

In my experience brass rivets will wear into the brake drum. I have run drums with groves from rivets, but how much brake you are giving up I don't know.


Cat had a different book for everything. So a operator's manual, serviceman reference for the tractor, and another for the engine, parts book for the tractor, and another for the engine. I have not worked on a loader, but if it follows the dozers, it will be one book for the loader and hydraulics will be a second book. Hopefully all the books you don't have are available in the library on here you now have access to as a member.

Thanks for the reply. Weird though, 69 views and nobody has anything to say about these loud bangs when using a dry brake. Loud and heavy enough that I'm expecting it to break a band. May try dousing it with diesel to see if that quiets it down, but seems too severe to just be sticky brakes.
How thin can these brake linings get before they cut a gouge in the drum?
Some web references say brake pops are due to low oil, but these older brakes and steering clutches are dry.
Need a manual with a thorough discussion of these brakes. Since brakes are not in the Traxcavator Service Manual, I assume the 955 is about the same as any D4 of the era. This 1956 955 has a 4.5x6.5 inspection plate looking right into each band from the back, also a 7x22 inspection plate under the seat. Looking at a 1937 RD4, I see about the same arrangement. If it can be done through those inspection ports, then might be reasonably easy. If I have to pull the steering clutches, not so much.
Yup, I'm now officially a Junior Boarder, but for some reason no access to the library. Did send email to help and to mary @acmoc.org, no response yet. Can get down into the library for a list of service manuals, nothing clickable, just the message "Join now to view these library documents". The manual "D4 Tractor Servicemen’s Reference Book form 30521 4-1953" might be best, apparently from 1953. I suspect this one is from the 1940's: "Servicemen’s Reference Book for Caterpillar D4 Tractor 4G, 7J, 2T and 5T Series Form 7490C".

Form FEO305212-02, Servicemen's Reference Book, covers the 4G,7J, 2T, 5T, 6U and 7U D4's.

Starting on page 75 and running through page 83 there are detailed instructions on removing and replacing the brake bands - both by removing the transmission cover and without removing the cover.

Both methods are miserable jobs. I have replaced them both ways and would never recommend trying it without removing the cover. Neither can be characterized as "reasonably easy". The fact that you are dealing with a loader only complicates the job.

The book calls for lining replacement when the rivet heads are "flush or nearly flush with the lining.

Now have access to the library. Many thanks! Yes, replacing brakes is not looking especially trivial.

when you apply the brake do you feel any feed back in the pedal as it makes noise? do the linkage feel loose or worn.

you say its a 56 model then it would be based on the u series d4.

Don't recall much if any feedback through the pedal, but then perhaps the noise was distracting me. Linkage doesn't seem especially loose. Serial number is 12A2122, which i believe makes it a 1956. Will read through the service manual about the brakes, then tear things down a bit further and do a closer inspection.

I don’t have near as much experience as most on here but are you sure the noise is from the brake band? Or is it just when the brake is applied it is loading up something else and then making noise? I would get a big bar and try wiggling the sprocket and outer bearing, check for metal in the final, hold some light pressure on both steering clutch levers hen you turn right and see if you feel a push in the left lever? Sometimes if track alignment is not good you might notice fresh shiny wear marks on the sprocket teeth or on the track chain. Hopefully give you a couple ideas to look at as I think you may have something more serious than a sticky brake. Good luck, Mike