Advice on hubs and spindles please

422flat6 · 12-11-2016, 06:25 PM

Today I was working on installing new front brake discs. The existing rotors have excessive runout. I haven't measured it but it's very obvious, turn the hub and the disc contacts the OB brake pad and gaps the IB, turn 180 degrees and the disc is contacting the IB pad and gapping the OB pad. It makes for a brake pedal that doesn't feel good, pulsates and engages too far down in the travel.

When I pulled the hub I found quite a bit of corrosion on the disc mating surface, including some lumps in the metal around the bolt holes that fasten the disc. I also saw some discoloration on the spindle where the inboard wheel bearing rides. The inboard wheel bearing is loose inside the hub. Only the outer race for the outboard wheel bearing is held in place by press fit.

Questions:
1) I need to have a machine shop face these hubs to make sure the mounting surfaces (brake disc and wheel) are flat and parallel right?

2) Is the discoloration on the spindle the result of the inboard wheel bearing race spinning on the spindle?

3) Is the inboard wheel bearing supposed to be a slip fit onto the spindle and should the bearing be loose inside the hub?

Anything else I need to consider or look at while refurbishing these hubs? I'm pretty sure if I try to mount new brake discs on them as-is I'll never be able to get a decent runout.

Brake disc mounting surface (after sanding off corrosion)

Discoloration on spindle where inner wheel bearing rides (on the non-tapered part)

Loose inner wheel bearing in hub

OffCamber00 · OffCamber00's Garage

Quote:

Originally Posted by 422flat6

Today I was working on installing new front brake discs. The existing rotors have excessive runout. I haven't measured it but it's very obvious, turn the hub and the disc contacts the OB brake pad and gaps the IB, turn 180 degrees and the disc is contacting the IB pad and gapping the OB pad. It makes for a brake pedal that doesn't feel good, pulsates and engages too far down in the travel.

When I pulled the hub I found quite a bit of corrosion on the disc mating surface, including some lumps in the metal around the bolt holes that fasten the disc. I also saw some discoloration on the spindle where the inboard wheel bearing rides. The inboard wheel bearing is loose inside the hub. Only the outer race for the outboard wheel bearing is held in place by press fit.

Questions:
1) I need to have a machine shop face these hubs to make sure the mounting surfaces (brake disc and wheel) are flat and parallel right?

2) Is the discoloration on the spindle the result of the inboard wheel bearing race spinning on the spindle?

3) Is the inboard wheel bearing supposed to be a slip fit onto the spindle and should the bearing be loose inside the hub?

Anything else I need to consider or look at while refurbishing these hubs? I'm pretty sure if I try to mount new brake discs on them as-is I'll never be able to get a decent runout.

Hard to say based on the pictures but you shouldn't have to have a machine shop reface your hubs. I have had good luck just sanding them to get a nice mating surface. Tape some sandpaper to a flat surface (granite counter tops work great

) if you are careful you can also use a fine metal file.

Make sure you use new wavy washers and torque everything properly and in the right order when mounting the discs.

Spindle discoloration is fine - as long as there isn't wear. It could be result of not enough grease.

Yes the inner race is loose inside the hub. That is how it is supposed to be. Everything lines up when the hub is pressed onto the spindle and tightened properly with the compression nut.

Good luck.

KTL · 12-12-2016, 07:55 AM

Yes i'd have a machine shop cut those hub contact surfaces so that they're all the same height. Disc runout is often caused by:

-Crap on the "hat" of the disc
-Uneven hub surfaces like you show
-Poorly installed wheel bearing races

Disc runout can be adjusted by clocking the disc on the hub. But the disc itself should have a nice flat hat to begin with so we don't even experience this problem.

Your spindle looks OK and i'd not worry about it. But since you're in there fixing things anyway, i'd install new wheel bearings which means new races in the hub. Remove the OB bearing and swab out the grease to see what the race looks like in there. Also remove the IB grease seal and swab out the grease to see the IB race. Then clean up the hub as best as possible and heat it up to 250-300F (outdoor cooking grill works great) and then carefully knock out the races with light taps from a hammer and punch. Installing new races is the same routine. Heat up the hub and freeze the races. The races will drop right in.

422flat6 · 12-12-2016, 07:57 PM

Thanks for the input. Good to know I don't need to worry about the spindle. What about just buying a good used set of hubs? From what I have read, the 69-73 hubs are 47mm offset and the 74 and up hubs are different. My car is a '72. Would any hub other than a 69-73 hub work?

donporfi · 12-12-2016, 09:29 PM

check here
Can anyone confirm: front wheel hub depth '67 vs later

KTL · 12-13-2016, 09:41 AM

Yup that link from donporfi has the images I was going to post. Thanks!

422flat6 · 12-13-2016, 10:38 AM

Thanks for that link! My only question now is will the 68-73 .04 hub and the 74++ .06 hub interchange since they're both 47mm offset?

The .06 hub is probably much easier to find. Also I eventually want to run 16x7" wheels up front so would there be any advantage to using the newer hub for that setup or not?