I need some advice on a 1955 D4-7U.

I need to replace the seals in my final drive. How can I remove and replace the sprocket? How can I press 25 Tons without removing the final drive from the tractor? Anyone ever replaced their sprocket seals, in their shop, without specialty tools?

Any help will be greatly appreciated!

There is no easy way to do that job outside of getting the proper pullers to do the job.Some independant mechanics have puller tools but not many so I guess it,s almost a dealer job that has the puller and installing tools.It,s not a sledge hammer job to do it right.The complete final drive doesn,t have to come off just to pull the sprocket and related parts to change the seals but some have taken the case and bull gear ith sprocket etc. off as a unit and taken it to a dealer or whoever and then have it taken apart which would save a road job expense.

I'm about to do this job myself and I hope with simple tools. I'm going to make extenders for a heavy breakdrum puller and with it fully tight heating the hub with an oxy act rosebud should make it pop loose. Putting it back I'll use dry ice to shrink the shaft and warm the hub to 200F and tighten the retainer real quick. I'm going to calculate what the stress will be in the hub to make sure this will work properly. This method is used routinely on 12 foot tug propellers that are transmitting 4000 hp at 120 rpm-that joint it not disturbed even when the prop. hits a rock and breaks the gear box.

You can get the outer seal without taking off the sprocket but your inner one is the one that is probably leaking. You at least need the large spanner wrench to get the bearing tighter nut off. It costs around $150. This is no easy job esp without the right tool, because you will have to put about a 6 foot cheater pipe on the end of it and bounce up and down.
If you get that point you will have to take the roller frame and track out the way. I removed the final drive case, sprocket and hub as an assembly from the shaft and took it to the dealer to have the sprocket pulled. He said it popped off at I think 50 or 80 tons. Then you got to get it press on at your shop some how probably a service call.

I replaced mine and used cheap seals that didn't fit right and it still leaks.

So looks like some special tools or Cat service will be needed or just pump the whole final drive housing full of grease.

Muzz

I just made the tooling today and it worked fine-total cost-zero. I used my old brake drum puller three 3/4 by 12 inch pieces of threaded rod, three 3by6inch plates 1/2 thich with holes drilled inthe center and six nutsIt took no more that 30 percent of what the puller could stand and no heat. The spanner wrench nut comes off easily with a blunted drive pin and a one hand sledge. The sprocket retainer nut comes of using a rounded 1 1/2 coal chisel and the same calibrated hammer. This same nut will force the bearing off which is of course necessary. I've done two with four to go as I am in the process of saving the good part of three D47U's. The earliest D4 a 1928 fresh out of the woods after 40 years is slowly making its way to the toyota factory. This final drive unit was covered with gear oil and uncorroded. What I see so far indicates that reinstalling the sprocket will be done by first tightening it snugly, heating the hub quickly, and slugging the nut - I'm going to guess 1/8 to 1/4 turn. As I mentioned earlier this is the way all propellers are done. This method will also put no stress on the inner bearing. I think the hardest part will be just getting to the hub. A very senior junior member. Jim

Did you get your sprocket off yet? I just did two more and the most time was spent in getting the first taper off which took two or three cycles with the heat and cold water. One sprocket came loose as I was rotating the spanner nut counterclockwise. to push the bearing off. The other sprocket was a bear because it had been installed with .005 shims arround the entire circumferance. I ended up flowing cold water thru the space between the solid and tubular axle and heating the hub. With three heat cycles it came loose. It never ceases to amaze me what you find in these old machines to keep them going after their usefull life has long gone. Jim

Jim, it sounds like you're quite talented at fabricating tools. I have about 1/4 of the D4 repaired.

Thankfully, I've found the guy's at the CAT Shop very helpful. They've given me a lot of advice, and have even loaned me a huge spanner wrench and a portable field press that has attachments for pulling or pushing.

My sprockets popped loose around 30 Tons, and the book suggests pressing them on at 25 Tons. How will you measure the amount of pressure you're applying to your sprockets?
Thanks to all of you for your expert advice!
James