Advise me on bearing removal and replacement on a harrow

HCJtractor · Dec 12, 2011

I am restoring an old Athens harrow. I finally got the castle nut off and am ready to tackle the bearings. I guess I will see how they look and feel before I buy new ones. This has been sitting outside for decades so it is rusted up pretty badly. If it is like the rest of the harrow, it will need some work to remove it. The shaft is 1 1/2".

I have not had time to start with the bearing removal, so before I begin, I would like some advice on how to remove them, and how to replace. Any tips would be appreciated. There is also a 3" grease fitting extension that is broken. Where can these be bought?

Johnp33 · Dec 12, 2011

What I would do is remove the bearing holder clean up the shafts edges, I would drill the end of the shaft, put the end back on, and use a guillotine, to back the bearing and a strong back, on the shaft to pull it off.
With the bearing holder off you want to see if you can get a number off the original bearing. Then you could just cut it off with a torch. not all the way threw, cut the outside and the bearings out then about 1/2 way threw then with a big hammer under the bearing hit with a hammer on the top should spread it enough to get it off.
It all depends on whether you want to try and keep it, and the tools you have available.

HCJtractor · Dec 12, 2011

I am not following you on this. Sorry. The bearing holder is the cast steel piece that holds the bearing and is in one piece, right? The two bolts do not need to come out, I don't think. Are the bearing and seal pressed into the holder? I don't understand "drilling the shaft." Judging by what they look like, I think replacing them would be best. I guess I just don't understand how this is put together.

Johnp33 · Dec 12, 2011

Some are one piece most split if you have to then the guillotine has to go behind it, and remove it as an assembly.
Drilling the center of the shaft is so the strong back has a guide position, you bolt the guillotine and the strong back together, and use the pusher bolt to pull the assembly off. Where you drilled into the shaft gives you a point so the pusher bolt stays straight, and that way it will not damage the thread on the shaft.

HCJtractor · Dec 12, 2011

Here is a better picture. I cleaned the housing so you can see it. THe housing is one piece. There appear to be seals on both sides. I assume it is pressed in place. Where do I go from here?

MHarryE · Dec 13, 2011

In picture 2 you see 2 notches in the housing. The bearing has a spherical outer race. When it was new and free of rust, you could take a new bearing , hold it flat, insert it straight into the holder through those 2 notches, and when the outer race hits the other side rotate the bearing and it would be locked into place. Now with it rusted up the trick is to break the outer race free from the housing. Then you can rotate the bearing horizontal so the outer race lines up in the notches and it will come right out. Then it is on to the store to find the right size. Square bore disk bearings are pretty pricey compared to round bore if I remember right. I looked over a disk before an auction last summer, saw it had 2 bad bearings, checked the price for new bearings on line and recall it was high enough that I didn't enter the bidding.

HCJtractor · Dec 13, 2011

Thanks. That makes sense. I could guess the notches had some importance. The new bearings are fairly common (gw211ppb3) and cost abouit $21.00 up to $37.00 depending on source, so that's not too bad. I need eight.

So you are saying when new, the bearing is inserted on edge into the two notches and then rotated into place. Does this require force with a press or mallet? I read to chill them first in a freezer or dry ice. I assume they are referring to this type of bearing.

So to remove them, any chance of reversing the rotation or will I have to cut them out? They seem very locked in place. Thanks for your input!

Mace Canute · Dec 13, 2011

Those are self aligning bearings so they are not a tight fit in the holder, just a nice snug fit that allows them to easily twist slightly. If you heat the housing (held solidly of course) to expand it slightly and lessen the grip it has on the bearing, you should be able to put something in the through hole to pry it around some, then grab it to get it fully 90 degrees to how it sits normally. It should be easy to tap it out then as long as it's lined up with the two notches.

HCJtractor · Dec 13, 2011

These bearings do not move even slightly. I guess the dirt and rust have them locked in place, even though I have cleaned them as best I could. I wonder if it would be easier to use a torch and cut through them from the center to start removing them piece by piece? Or maybe I can use a shop press and press on one side to try to rotate it out.

Mace Canute · Dec 13, 2011

Yes, YOUR bearings are seized in the housing...I described how those type of bearings are supposed to work. I suppose I should have said that but I didn't think I needed to.

Heat is your friend. Heating the housing will expand it...the expansion should break the bond that the rust has created between the bearing and the holder allowing you to muscle the bearing into position to remove it. You will have to reef on it! You aren't going to be able to do it with your fingers.

I wouldn't use a press...to much chance of breaking the housing before you get the bearing to rotate.