what are the four holes for in the bottom of the TO-30 differential case?

[Mike476]

I'm used to cold soaking landing gear trunnion, drag strut mounting pins or other hardware prior to "inserting" them into a bushing or load bearing surface. Can't cold soak the axle so in this case application of heat to provide the clearance necessary is the best option.

 

[dbotos]

I've got a 1200-Watt heat gun that does 1100 deg F on high, 650 on low. I might try wrapping some insulation around the shaft and blasting the collar with that (with one of the concentrator tips installed).

 

[Mike476]

Certainly worth the effort I would think.

 

[Coyote machine]

I gave it some more thought. What about heating the collar and then pressing off the entire retainer bearing and collar all at once? The collar should heat up with a focused torch flame at a different rate/amount than the axle shaft. It that doesn't work, you could still mill off enough metal and then try the same process. If you mill the collar in 2 or 3 places then use heat and a press, something's got to give.

 

[ljohnson778]

Lot of guys I know will weld a bead around it with their mig, and it comes right off.

 

[Mike476]

Lot of guys I know will weld a bead around it with their mig, and it comes right off.

Don't know why I didn't think to mention that, I have heard of people doing it in the past.

 

[dbotos]

I succeeded in making the basement smell like burnt grease tonight (hooray for good 3M respirators). Hung the shaft from one of the rafters just slightly off the floor. Ended up removing the studs from the casting since they were in the way. Hit the OD of the collar all around with the flat concentrator tip on the heat gun set to high for about 15 minutes. Made grease run and a little smoke. Probably just managed to heat the outside layer of the collar and the air was cooling it too quickly. With those aluminum heating rings, it has the advantage of heating from all around the diameter all at once, plus it shields it from the air.



Here's a video of one of those heating rings in action:

http://www.schaeffler.com/remotemed.../schaeffler_mt_11_fag_hearing_plate_de_en.mp4

With the welding, is there any danger of arcing through the bearings? I guess if you put the ground clamp on the unfinished portion of the shaft between the collar and the inboard (splined) end, no appreciable current should go through the bearings. I've got a TIG that I could use if I go that route. Will have to clean everything with alcohol before I do that, though...

 

[Coyote machine]

Nice setup in your shop. I still think you're going to have to cut and press or drill and press the whole assembly toward the floor. The heated ring works because of access which you don't have. So maybe you need to try to freeze the shaft in the ring area and then pound/press the ring and assembly off the shaft.
I'm trying to think how you could accomplish freezing the shaft enough to have the collar want to slide off the shaft with pressing on the assembly, or using an impact gun/chisel/hammer to get it to move?
Anyone have a freeze method? Freon? Something else?
Wild azzed guess; try freezing the shaft AND heating the collar simultaneously. Stick shaft in large bucket of ice, heat collar with heat gun/torch, slam down on head assembly with sledge hammer?!

 

[Mike476]

You shouldn't have to worry about current through the bearings. I've never used TIG, MIG with gas all but eliminates spatter, you would get a little with flux core. I would want to protect the bearings from that.

Would be nice if able to cold soak the axle, I don't know of any effective and safe way to do it other than letting it sit in dry ice for a period of time (determined by the type and thickness of material). It sure does work well though when fitting close tolerance parts.

 

[dbotos]

Did some whittling on the collar last night. Made a cardboard shield for the bearing and plunged the collar with a 1/2" end mill. Since I didn't have a big t-slot cutter, I took the shaft out to the garage and attacked the collar some more with Dremel cutoff wheels (bearing shield still in place and shaft protected with a steel can with the bottom cut out. After doing that, I decided to just mill a big flat across the collar with a shell mill so I'd have more room to work on it with the Dremel. Will probably take some more material out with the Dremel and then see if I can heat the real thin part that's left with the heat gun (if it doesn't just pop on its own when it gets really thin).