Pressing Force Required:

How much force is required to break the sprockets free of the splines on an early HD-21?

Thanks, I have a new 60 Ton hollow ram cylinder ordered as my current 30 Ton is not enough force for this job on either side. 

apply force gradually while smacking ring with a sledge hammer.  greatly lessens the force needed than just pulling on it.  

According to the pressure gauge, and cylinder bore size calculations, 32.6 tons and shock loading the sprocket(s) with a 12# sledge wasn't enough..... 

Hi Mel, yes I am working with two HD-21 series tractors now. One is a well worn but running parts machine, and the other will be very nice once I get the sprockets rebuilt and a P&B turn performed along with a couple of bottom rollers that are suspect. This is my first attempt doing the task using my owned tooling, but have done the same job numerous times in the past with employer furnished press/pullers.

You'll need a press to reseat the sprockets also as this will take upwards of 30 ton on that size tractor. It can be done with a wrench and long extension bar but it's not the safest way to do the job..... 

On one HD5G I just welded the new sprocket ring onto the old spokes after cutting old sprocket off . Cut a section of new sprocket ring to slip over the truck frame , then welded it back together when welding spokes to ring . 
 Other 5G I cut the truck frame to put on replacement sprocket and replace axle , made a plate to bolt to truck frame to keep alignment right - then cut frame , got everything back together , bolted cut piece on , welded truck frame beck together and removed plate . 
  Tightening the sprocket nut called for 1,200 ft lbs of tension so used 10 ft length of pipe on my wrench handle - went back about 9 ft from nut and put my weight onto pipe until nut stopped turning . then a little extra force to make sure it was tight .
 On the 5 sprocket with large splines the sprocket came off easily with just shock from sledge and bottle jack and chain .

All  four sprockets pulled free with a borrowed "Enerpac" press/puller I copied mine from. 

There was a nest of HD 21's around here  -not me, so this is a bit vague.  

Picked up another job today while delivering a farm tractor after repairs. This one is a JI Case 1155D Track Loader. Supposedly runs well but hasn't been out of the shed since summer of 2017. Needs minor undercarriage work but a P&B turn and new drive sprockets will take care of it. Idlers and rollers appear fair, but serviceable. What is really needed is line boring of the linkage arms for the bucket apparatus as they are very loose. This is work I'm set up for so we'll see what the future holds. 

Set my line boring welder up to weld up the gullets of two drive sprockets today and it really works slick. It took about an hour each sprocket but the weld deposition is perfect with good overlap, and being a machine weld, is very even. I then hand welded "crowns" which will serve as teeth tips when machined to size.

Son in law and track man/friend did the P&B turn over the weekend while wife, daughter, grand daughters, and I went through the Caterpillar, and riverfront museum(s) in Peoria. No word yet on the sprockets as still early, but I'll pick the tracks up later today or tomorrow.

what did you think of the Museum ?  Have never been there, but thought about it .