Hi all,
As you already know my rebuild is moving along. I went back to the passenger side front brake assembly to troubleshoot some more. The first try showed me the rotor assembly was out .010 . The driver side is a mere .001 . So I put the indicator to the pass. side hub yesterday ( non-riveted assembly) and found the hub to be out at .009 . The specs call for .002 for the whole assembly. I readjusted the wheel bearings just to be safe and have zero movement. Then rechecked the hub and it is still out .009 . IS IT POSSIBLE MY HUB IS OUT? I didn't think the hubs deflect much. With the old rotor, the assembly reads .006 . Obviously, the assembly was turned together to help the issue. Now, that caliper was leaking on tear down ( this is what lead me to get o-ring calipers). Has anyone ever had this issue? Should I try to find a new hub? Could there be something wrong witht the spindle itself? I would like to get this dead nuts on so my new caliper does not suffer from the same issues. (Taking the spings out of the caliper is not in my bag of options...) ANY HELP WOULD BE GREAT. I TRIED LOOKING FOR HUBS AND CAN'T FIND ANYONE WHO SELLS THE HUBS ONLY!!!!!!!!!!!!!!!!!!!!!!!!!!!! :confused: :confused: :mad :mad :cuss

 

Did you take the rivits out yourself? If so you will have to take a little grinder over the rivit holes. Don't take of much, just a little to take any lips off. Did you rotate the rotor on the assembly. You should try it in all 5 different postions until you get the lowest run out. Try those 2 things and see how you make out. I don't think you'll need a new front hub unless your bearings are spun. Front hubs don't really warp. Actually let me say that it's uncommon for them to warp. We don't find many here when we do them.

 

Hi-
The rivets were out from the previous owner. I did rotate all five holes, actually marking each spot with a sharpy pen. I wire wheeled the entire face of the hub just to make sure there wasn't any debris around studs at the base. I understand what you are saying about the rivet holes. However, I put the dial indicator on the hub also. The hub itself runs out to .009 When I set the indicator to the lowest point (.000) there is only about a 1/2 of space with it stays at .000 then starts to going up eventually hitting .009 . I took this reading above the studs ( almost touching them) Then I took a reading and the base of the hub (closest toward center) and the reading showed .006 . Could my hub still be the issue. I played with this for 3 1/2 hours yesterday trying everything I have read about. The wheel lug went on correctly and everything. I am stumped! :confused: :confused: :confused:

 

Also, I don't want to shim out the rotor. I believe you wrote sometime ago this was a temporary fix. I want a permenant fix.... do you sell hubs if I need one?

 

It was nice speaking w/you earlier. Sounds like you took all the right steps. Seems to me the hub is out.

 

I had the same issue on mine. Mine had a similar wobble.

I marked the hub face and noted the location of the worst runout, removed the hub and chucked it into my lathe, making sure to mount it with the exact same degree and location of wobble. Then I just took a few facing cuts off the mounting surface until it was all nice and clean. Reinstalled the hub and measured .000 runout.

Mike P

 

Hi Mike,
Sounds like this worked for you. I am concern about have a hub that is essentially "out of round". Even though the lathe could mill down the high point, the hub itself would still be out of round. Don't get me wrong, if it work for you.. AWESOME... but I am thinking this fix is along the lines of shimming the rotor...??? :confused:

 

What is wrong with shimming the rotors? I trued up all my rotors then fine tuned some of them with thin shims until I had 0 run out. I mark the wheel, a stud and the rotor with a dot of red paint and always be sure to reassemble with the dots lined up.
As for truing a hub in the lathe it is not making it oval to true up the mounting surface.
I would not run with .009 runout but other then truing up the hub surface why not shim?

 

I understand your concern about machining the hub.

But, originally, the hub was a wobbly casting (or forging) at the factory and GM machined the bore and mounting face with the hub mounted in a lathe.

Since the hubs aren't out more than a few thousandths, truing them up doesn't take off more than a sheet of paper's thickness or so. As long as the mounting face and bore are true, it won't matter if the as-cast hub surfaces are out.

I too, didn't want to shim the rotor, it was just easy to machine the hub, since everything was apart anyway. And, the problem with shimming is the shim stacks would want to be either tapered (very difficult) or all of varying thicknesses (also rather time consuming) to get the rotor to mount perfecly rigidly to the hub face.

My '68 is a full time, completely prepped autocross car that does not get babied, and I haven't had one ounce of problems with the hubs since I trued the one side.

Mike P

 

THanks Mike ... sounds good