Help: Can't Get Front Wheel Bearing Races Pressed In Evenly
 

I'm having great difficulty replacing the inner front bearing race.

I modified the hub as shown in the MazdaTrix howto, and removed the old races. I removed all burrs, and installed the new races, but they wouldn't seat.

I heated the hub up in my oven at 400 degrees for two hours, and the outer race fell into place and seated properly. The inner race had to be pressed in, but it still won't seat all the way down. It is about half a millimeter off, with one side slightly closer than the other, and simply will not move any further. Any ideas what the issue could be?

You will probubly have to heat it up again and either try lifting the low side up or the pushing the high side down.

I also did mine but it didn't turn out very good. I don't have the proper tools.

The race probably galled on the aluminum and has scraped a bit of aluminum down into the groove. You'll need to remove it, clean up the hub and try again.

For future reference, here are two tips on the FC bearings...

1. To remove the race, the easiest way is to use your welder. Run a bead along the inner edge of the race and let it cool. The welding expands the race when it heats up, but pulls it in as it cools. The race will then be loose enough to virtually fall out.

2. To Install, freeze the race in a small dish of oil. Heat up the hub and then use the old race to press in the new race. If you have a press, use it. Otherwise a big vice is the next step. Auto parts stores also sell bearing race drivers that you can use with a hammer.

I'll remove the race, clean up the hub, heat it up, and try again.

Freeze it in the oil like Aaron said too. It works.

I have frozen parts to shrink them before but never in oil.

What does the oil do?

Well, I removed the inner race, placed it in oil, and put it in the freezer for about three hours. I cleaned up the hub. There were a few aluminum shavings, but they seemed to be caused by the use of the old bearing to press the new bearing in (they were not lodged between the bearing and the seating surface).

I heated the hub for two hours at 400 degrees. I removed the hub and immediately placed it on the press, then I inserted the race. It pretty much dropped in, but it didn't seat, so I pressed it using the old race. After all that it still won't seat. There is still about half a millimeter or so of space between the seating surface and the race. I'm not sure what else to do. I'm using a 12 ton shop press. Is this simply not sufficient, or am I missing something?

Although I've never replaced any bearings on my car, just wondering if the other side gave you trouble when you installed it provided you replaced both sides.
Second, maybe the tolerance of the bearing is off, try another or see how the original fits. Maybe the hub is wacky causing you to replace the bearing in the first place.
A 12 ton press seems more than enough. I usualy just freeze and properly hammer bearings in to place, if need be.

Lubricates during pressing.

I don't know what to tell you. If it doesn't fit then the race is wrong, something is jamming it, or you're doing it wrong (which doesn't seem to be the case).

Today, I pressed the original race into the hub. It seated perfectly. Next, I tried to press a new race (the one intended for the other side) into the hub. Same problem. Finally, I pressed the new race into the other hub (yes I am doing both sides). Same problem. Looks like the races are incorrectly sized, or simply the wrong bearings. I purchased them from MazdaTrix so I'll be contacting them tomorrow to see if I can get any useful information.

Good tip, ive done it without oil, and then added room temp oil after. It thaws it out a little bit though, and have had some parts get stuck halfway, only for me to redo it all over again. Thanks

I carefully compared the old races with the new races. The new races have more material that contacts the inner hub wall than the old races. The outer diameters are similar, but there is more material along the height of the new races. In addition, the new races are slightly less rounded at the rear seating surface than the old races (due to the extra material along the height).

I spoke with a person from MazdaTrix, and he said that he has never heard of this problem before (initially he thought the races had galled as well). He suggested that I have some of the outer race material removed so that they are similar to the old races. I'll be doing this as soon as I can get them into the machine shop, and I'll update this thread if it worked or not.