How to free a frozen shaft?

[sudsmaster]

I have a 15 year old MTD rear-tine rototiller. While I have been good about maintaining the motor (yearly oil changes and regular air filter and spark plug maintenance), I neglected to follow the manual and annually remove the wheels and tines and lube the shafts with grease. Probably because it didn't make sense to me. Apparently the reason for that procedure is to prevent the wheels and tines from rusting solid to the shafts. So it makes sense to me now...

Well, I finally got around to it last week. The tines came off easily - plenty of space between the tine assembly bore and the shafts. But one wheel refuses to budge. I've tried just about everything. Lots of PB Blaster rust penetrant, a wheel puller, hammering (I know, not suppose to hammer on it, but it seems to have survived that part ok). I wasn't able to put a lot of force on the wheel puller because I could see that it was bending the outside the rim at a certain point (the rim resumed its normal shape when I removed the puller - good steel!). In my research on it, I've found that the best penetrants apparently are a product called Kroll Kroil, which is not available in most stores, but is available on-line, and perhaps Liquid Wrench. I have a product called Free All Oil Penetrant on order, but I don't know if it rates as well as Kroll. I figure I can get Liquid Wrench locally so that's the next thing I'll try. Does anyone here have a favorite rust penetrant?

The other suggestions I picked up on-line were:

1) Weld a large fine thread nut on the center outside of the wheel, with a ID less than that of the axle shaft. Then use a bolt in the nut to force the wheel off the shaft. A peunumatic hammer/wrench (like used in the auto trade) is recommended to free the axle. The nut can then be painted over and left on for future use if needed. Since I have a flux wire welder setup, I could probably do this... just need to fire it up (never used it, although I once took a class) and do some practicing first. Don't want to wind up welding the wheel to the shaft!

2) Remove the hitch pin that normal prevents the wheel from spinning off the shaft and then use the tiller normally until the wheel loosens. I've tried this already but with most of my garden already tilled didn't have a lot of time on it, and the wheel is still stuck solid. I might be asking neighbors if they need their gardens tilled... LOL...

I can leave the wheel frozen in place but it will get in the way should I ever need to pulls the axle to service the axle seals. And it bugs me that I can't get it off, even though it's obviously all my fault.

Right now the tire is back on the wheel, inflated, and I tipped the tiller over so that I could dose the inner union between the shaft and wheel hub repeatedly with PB Blaster. When I get the Liquid Wrench I'll switch over to that. Anyone have a favorite rust penetrant? I figure we get washers with parts frozen together like this so some of us must have found a product that works well.

The axle shaft in this case is 3/4 diameter, and it looks like the wheel hub covers about four inches of the end of the shaft. And it's fairly snug fit, not a lot of play on the wheel that was not frozen. That's probably why it's so difficult to free once the rust sets in.

If all else fails I could probably take an angle grinder to the wheel, which would destroy it, but I'm saving that as a last option.[this post was last edited: 4/13/2013-15:04]

 

[wiskybill]

My older brother used to work on old cars quite a bit.

He told me once that the best penetrant that he used was a 50/50 mix
of lacquer thinner and automatic transmission fluid.

Bear in mind that my brother was cheap, but he said it worked,
along with patience. I have not tried it myself.

At this point it's worth a shot and you may already have the ingredients.

 

[goatfarmer]

I've heard ATF, and acetone is a good penetrant.

 

[wiskybill]

Thanks, Kenny

for jogging my memory. It was acetone and not lacquer thinner.

It's been some time since he told me this and I was remembering
the wrong thing.

 

[58limited]

I don't know much about rototillers so excuse a dumb question: Is this wheel you are trying to remove metal or rubber? You can apply heat to the stuck metal wheel, it will expand as it heats and hopefully break loose from the shaft.

 

[sudsmaster]

1) Yes, I saw a mention on-line about 50/50 acetone/ATF. In one test, it was the best. But in other tests, it didn't do so well. I did find some Liquid Wrench (a vintage can in the garage from 1960) but ... the stuff leaks out the pin hole on the engine side of the wheel, and it simply can't get into the hub from the outer side.

2) I have indeed tried heating the wheel. Used propane torch at first; that didn't work. Then I went to MAPP gas, which got everything fairly hot, but still the hub is stuck to the axle like glue. Of course I took off the tire before I did this.

3) Soaking overnight with PB Blaster, and then for about an hour with the Liquid wrench... nothing... Same problem.

4) There is a $250 tool available on-line specifically for pulling such stuck wheels. It's a brace you put behind the tire, and then there's a second piece that goes in front with a big screw, and you use it like a wheel puller. I've been trying the same basic thing with a real puller, but since it hooks onto the outer edge of the rim I'm afraid to apply too much torque to it. I can see the rim bending as I do it but so far it's regained its basic shape afterwards. There's probably a point of no return where it will remain bent, and I'd like to avoid that.

5) Right now the tire is back on the rim, the various side covers are all put back on, and the tiller is waiting for a better solution. Maybe next season (my garden doesn't need any more tilling now) the wheel (left the pin out) will unstick itself in use.

6) Located a suitable nut and bolt in the workshop (5/8 OD fine thread). I might try welding the nut onto the outer side of the rim and then trying an impact (air) wrench on it. First have to get some flux core wire and also practice a bit with it first.