What is the differences in the pre-3/99 and post-3/99 wheel bearing hub assemblies on these Super Dutys? Can't find a "tech" that knows.

Reason I'm asking is that I've just had a post-3/99 installed on my truck and all seems fine. The mechanic said that everything "fit like a glove". To maken sure I went down in the pasture where the mud was about 18" deep and tried to get stuck. The front axles/wheels/tires were quiet with no popping or grinding at all. Locked and unlocked like new.

Anybody got an idea?

My rig: 1999 (build date 11/98) DRW, 4x4, manual tranny, V10. 4wheel ABS ESOF

 

Just got off the phone that a referral from a Help Desk clerk referred me to. He said he didn't actually know, but that the part numbers were different.


Here's your sign!

 

You need to run the later rotors with the later hubs. From what I understand there is a 0.070 difference in the sizing where they meet. I've changed my early 99 hubs to the later geometry, but I also put on the later rotors. It's the braking where the issue will be, not the driving or turning.

 

This is what I have heard as well. From what other people have told me, an early hub with a later rotor wont physically work together, so if there was going to be a problem, it would have already happened.

 

I'd think so too...and the rotor fit has been no problem at all.

Maybe it's like the Bigfoot/Chupacabra myth...you hear about such, but there's absolutely no proof to back it up...

 

This here is a tough one, ain't it?

I got a number for the "up to 3/99" which is HA590425 (Timken).

The National (BCA) number for the "from 3/99" is 515025, which I had installed on my "up to 3/99" truck. Called another dealership today and the tech told me that it won't fit. I asked him why. He didn't know. Sounds like Bill Cosby's kids...

 

Just a little more info:

Got an email from an FTE Sponsor that he looked it up, but it didn't give the difference. The only thing he could find was a difference in fine/course threads for an SRW - which doesn't apply to me.

Still looking...

 

You want to run the hub that matches the rotor. They are made for each other and I have read in TSBs that they cannot be mix matched - Ford Mo Co. will not cover repairs due to the tech using the wrong rotor - it would be the tech/dealer's fault.

 

Thanks for the come-back, mizzitch.

What difference is there in the rotors?

 

I think the difference is that some part of the rotor hat is thicker.

 

Makes sense.

Still, what part of the hub assembly would affect that - or, what affect would the rotor have on the hub assembly that a whole different setup be made?

I contacted FoMoCo via email after their robot refused to gimme her maiden name... ...maybe they'll get back with me before the other side goes out and I have to replace it with the wrong part...

 

The reason for the change was the early 99's started showing some premature brake wear, pulsation, "warpage," etc. So they moved the hub surface 0.070 and the mating part of the rotor by 0.070. Of course it didn't change the fact that many people still have trouble with their brakes. I personally think the early 99's were fine since I got about 150k out of my rotors. I also would not drive the truck until you got the right setup. It may work ok at first, but my guess is you're putting unnecessary strain on some part of the assembly, whether it be the rotor or caliper, and it's not going to work for long especially in a panic stop.

 

Thanks for the reply, Fat Diesel.
There's absolutely no stress on anything, anywhere. The brakes don't pull and under load I apply the brakes pretty heavy sometimes.

If the hub surface was moved outward .070" then I would think it would be better. Is this what they've done...just moved the hub surface, rotor contact outward? Or was it inward? Seems like it would have to be one of those two.

 

If you use a newer bearing on an older truck you need to use washers to space out the caliper bracket or use the newer rotor and you will be fine.


Dick

 

Thanks, Dick.

My question now is Why? If the caliper bracket is not out of alignment, why then does it need shims? The newer hub assembly is not causing the rotor to bind on the caliper at all.

I know that FoMoCo is not a herd of idiots and would not create another design if they could upgrade an existing design. What I'm having trouble with is that I'm hearing there's a difference in design, but can't seem to find out what it is.

I now have enough miles on the replacement hub for it to have shown some sort of trouble. I checked it a few minutes ago and there's nothing wrong with it that I can tell. It's got me puzzled to tell you the truth.