Someone explain Ford 9" bearings to me...

[Pete Whitstone]

My axle, and every one I have seen, is a tapered roller bearing setup. The taper is about 15 degrees, but is pretty obvious.

I sure don't understand the statement about the "end play ends up being controlled by the bearing". How does that work? If the end play is too tight the bearing is going to end up crushed. If the end play is too loose, the bearing isn't going to hold anything up, it will act like a bad wheel bearing and allow slop.

The only thing I can think of is that either the bearing itself, or the race it goes into, is designed to slip a bit as you tighten the retaining plate bolts. Then you would end up with the correct fit. But it also seems that you would not want to be putting the bearing under that kind of strain while you were actually tightening the bolts. So I'm not sure that's it either.

As I said, I'm only relatively familiar with the ball bearings in my axle. I didn't know before, but obviously do now, that there are also Ford 9" with tapered roller bearings. I still don't know anything about them though so I won't say much about them.

As to the end play being controlled by the bearing, in my axle the outer race of the ball bearing is held tightly in the housing. The outer race bottoms in the counterbore in the end of the housing, and the retainer plate holds it tight. So there is no end play associated with the fit of the outer race since there is no freeplay in the outer race.

And the inner race is pressed tightly on the axle shaft, with the heavy retaining collar being pressed on as well to ensure that the inner race doesn't move on the axle shaft.

With no movement between the outer race and housing, or between the axle shaft and the inner race, all of the movement is in the bearing itself.

Again, this is with the ball bearing setup in my axle. I don't know how end play is managed with the tapered roller bearing.

.... He removes what are clearly roller bearings, and replaces them with TIMKEN SET-20 which he never actually shows but I assume are roller bearings as well. He keeps the bearing race on the bearing at all times so you never actually see the roller bearings....

Here's an ad for Timken SET 20 bearings where you can see the ends of the rollers. Again, I'm no expert on this, but overall the bearing set looks very similar to the ball bearings in my axle, with the inner race, outer race and rolling elements (balls or rollers) all contained in one assembly that isn't intended to be disassembled. In the picture it looks like the visible end of the rollers is captured by flanges on both the inner race and the outer race. If that's true on the other side too (and I suspect it is), then this bearing would also control the end play.

But that's just off my seeing the picture, so no guarantees.

I didn't really look up the Timken 20 product, but yeah you are right, it does appear to be a non-tapered roller bearing set. In which case it would not matter a great deal exactly where in the housing it sits. It could be flush with the stop at the back of the housing, or it could be more towards the retaining plate side and I don't see that it matters. That would absolutely not be the case with tapered roller bearings.

I'd consider switching to non-tapered roller bearings like these, if it didn't mean having to break down the old ones already on the axle, which are super-low miles.

[Pete Whitstone]

I just watched the video. I remember seeing it a few years ago too. I think that you will find some differences between the currie aftermarket 9" axle that he was working on and the as issued f series axle in your truck.

I don't really see any obvious differences. What exactly are you referring to?

[Pete Whitstone]

But I think that's the answer to my question - the bearing race slips into the axle housing the correct amount on installation. That sets the bearing race in the proper location - for that particular bearing set.

Well, I'm wrong again. The REAL way this works is that the bearing itself sets the clearance. The bearing "carrier" (with the roller bearings) and the bearing race meet each other at their edge. So when you put the two halves together, the proper clearance is established by the two mating edges of the two halves.

So the bearing DOES get driven all the way into the housing up to the stop. And the reason it's safe to drive the bearing in is, while you're pushing it into the housing, you are not putting pressure on the roller bearings, the carrier is acting as an installation tool for the bearing race.

Duh. I feel kinda stupid now.

[mat in tn]

But I think that's the answer to my question - the bearing race slips into the axle housing the correct amount on installation. That sets the bearing race in the proper location - for that particular bearing set.

Well, I'm wrong again. The REAL way this works is that the bearing itself sets the clearance. The bearing "carrier" (with the roller bearings) and the bearing race meet each other at their edge. So when you put the two halves together, the proper clearance is established by the two mating edges of the two halves.

So the bearing DOES get driven all the way into the housing up to the stop. And the reason it's safe to drive the bearing in is, while you're pushing it into the housing, you are not putting pressure on the roller bearings, the carrier is acting as an installation tool for the bearing race.

Duh. I feel kinda stupid now.

you figured it out! there is absolutely no reason to feel stupid. one of the differences is the retainer plate and another is that you should have non tapered rollers. the timken set 20 is a tapered set. one of ways this gets confusing is the fact that the ford 9" has become the standard design for years as a hot rod and racing conversion. so, there are a few companies making ford nines that are NOT ford nines. custom housings for 28, 31, 35 splines etc. the one in that video was one of those and not a ford truck.in the truck the depth is set by the bearing in the housing captured by the retainer plate on the outside and the locking collar on the inside. the axle can carry weight evenly on the strait rollers better this way. the splined ends just spline in and are carried along with the carrier in the carrier bearings.

[Pete Whitstone]

one of the differences is the retainer plate and another is that you should have non tapered rollers.

"Should have" is kind of a maybe in this case, I'm not working with the trucks original 9". I took it out so I could put another 9" housing in, the one I've been adapting the Dodge brakes to. While the bearings from the old axles went into the housing just fine, I found that the retainer plate has a different bolt pattern on it. I was aware that there were different patterns but I always heard them associated to the bearing size (big bearing is one pattern, small bearing another). After measuring, I find the housing with the Dodge brakes on them to be a "new style" or "Torino" style. So I have to change the retaining plate.

[Pete Whitstone]

OK next question. In the stack of stuff on the axle, you have this from the inside out:

Retaining collar

Bearing race

Roller bearing

Seal

Retainer plate

So is the seal pinned in place by the retainer plate and unable to rotate, making the point of "friction" (point of movement) between the diameter of the axle shaft and the outer (smaller) part of the seal?

Or does the seal rotate with the roller bearing, basically fixed in relation to the rotating axle, which would make the point of friction the other end of the seal?

I hope that question makes sense. Thanks!

[mat in tn]

OK next question. In the stack of stuff on the axle, you have this from the inside out:

Retaining collar

Bearing race

Roller bearing

Seal

Retainer plate

So is the seal pinned in place by the retainer plate and unable to rotate, making the point of "friction" (point of movement) between the diameter of the axle shaft and the outer (smaller) part of the seal?

Or does the seal rotate with the roller bearing, basically fixed in relation to the rotating axle, which would make the point of friction the other end of the seal?

I hope that question makes sense. Thanks!

i kind of look at it from the axle in. axle, retainer plate, seal facing the bearing, bearing, collar. the seal sits on the recess of the bearing and the larger part gets sandwiched "held" in place once the four bolts are tight and the wear/slip point is at the axle surface.

[Pete Whitstone]

the wear/slip point is at the axle surface.

Thanks, that's kind of what I figured. The reasoning being, if the entire seal was able to turn with the axle, then there would have to be some lateral (in and out) play in the axle to allow that, and what happens when you go around a corner and the seal is forced into the retainer plate?

 

[mat in tn]

the wear/slip point is at the axle surface.

Thanks, that's kind of what I figured. The reasoning being, if the entire seal was able to turn with the axle, then there would have to be some lateral (in and out) play in the axle to allow that, and what happens when you go around a corner and the seal is forced into the retainer plate?

withe locking collar there is little to no walking . on an 8.8 the axles are held by a c clip in a recess with the "walking" end play held against a main center axle pin. the 9"is locked in place at the collar.