Aftermarket SI front hubs

Anyone had trouble with new hubs in that when the bearings are set, the disc wont align with the caliper like the original did and also when the bearing nut is tightened to where it should be the nut wont go on far enough to get the cotter pin in???

Double check that you have your bearings fully seated.

I’ve since removed the bearings and done some depth measurements, comparing the original hub with the new…they’re not the same to the tune of about .040 at the front and about .015 at the rear…these differences add up to the hub not aligning with the caliper or the hole in the stub axle through which the cotter pin goes.

That sounds very wrong. Doesn’t sound like you have been sent the right part.

Not sure 15 thou makes a difference does it? File the required nut slot a fraction deeper?

Hello Les,
Depending on the direction of the error of each of the bearing cup seats, a total of 0.055" could apply to the position of the nut. But with regards to the position of the rotor, only the error of the inner bearing cup seat will affect the position of the rotor (0.015"). However, if the manufacturer got it so wrong with the bearing cup seats (they would be made using CNC machine tools where 0.0005" is not overly difficult to hold and 0.001" is a dozzle"), I would suggest checking the position of the face that the rotor bolts to, relative to the shoulder where the inner bearing cup seats. Error in this relationship will have the greatest affect on the centering of the rotor with the brake caliper.

Regards,

Bill

It’s not just the 0.015 Pete, that moves the hub outwards then you add the 0.040 to it and the nut no longer goes on far enough, about two or three threads as far as I can see.

I intend to recheck and rebuild everything again today and see if anything changes…I hope so as I really don’t want to go through a lot of hassle trying to sort out parts/delivery times with the supplier.

Les,
Do you really need new front hubs?
I’ve only ever replaced the rear as the front don’t appear to suffer the abuse.

Hello Les,
The pitch of the thread is 0.05556" (18 TPI); accordingly, your accumulated error of 0.055" will only involve a maximum of one thread pitch. If you’re seeing an error of two or three threads then there is something else causing the cotter pin hole misalignment. Either the bearing cups are not pressed all the way home, or the cotter pin hole has been drilled out of position.

Regards,

Bill

I can see part of the cotter pin hole, and the hole drilled in the hub is out of line with it. Something is out of wack, I’ll check things out further today.

As far as how much thread I’m out…with the nut tightened and then I compare where the nut is on the axle with where it is on the other side (old hub assy still on) it’s quite obvious that the new hub assy is causing the nut to be further out than it should be. Might be just one thread but that’s enough to prevent the required alignment for both the cotter pin and the caliper…as compared with how the old hub was/is.

Doug,
The old hub looks to have the rear bevel, upon which the wheel locates, worn down to a grooved section. I have assumed that this is not normal and as a result, ordered replacements.

Also, there’s some corrosion on the hub, between the threaded section and the splines.

So I know this will come as a shock to you guys, but, it wasn’t the hub after all!!! I know, amazing isn’t it?! Well, it was and it wasn’t. I removed the bearings, checked the seats in the hub, outer bearing races etc…couldn’t see anything wrong other than the measurement problem (there’s that physics thing again) I explained yesterday.

So, I began reassembly starting with the rear outer race but this time I made a small ninety-degree “feeler” pick so that when I felt the outer races were seated, I could test them with said pick. Put the assy on the 20 ton press and pressed in the rear and tested. Seemed like there was a gap between the race and the seat, so gave it some more pressure, no change…hmmmm, well in for a penny etc…put it back and hauled away with the press and just when I was about to stop for fear of breaking something, there was a very loud bang and the press, and I, jolted…I’ve broken something I thought. Took it out of the press, checked for a gap with the pick, no gap!! Maybe just maybe this was the problem! Put the front race in, no problem and no excitement either. Assembled the hub and bearings to test on the car. Guess what, it fitted perfectly…amazing isn’t it! And just for good luck, as I put the tools away for the day (RH side tomorrow) and walked away, I ripped my shin against one of the arms of the lift…Fu^$^$^%$^%$!! but at least the hub, caliper and wheel are on ok!

Clouds and linings I guess.