1966 Front rotor and hub assembly

[Michael G.]

Is it possibly to drill out the rivets on the front hub/rotor assembly and bolt the hub into a new rotor assembly ....safely? Possibly using grade 8 bolt and locking nut. Is anyone offer a new rotor/hub assembly for a 1966? Any help apprecited, thanks in advance. Mike #28614

[Michael W.]

Re: 1966 Front rotor and hub assembly

There's no need to rivet or bolt new rotors to the hub. The wheel lug nuts do a perfectly acceptable job of holding things together.

The rivets were there purely for ease of manufacturing and transportation, once assembled on the car they became redundant.

Why are you intending to separate them?

[Michael G.]

Re: 1966 Front rotor and hub assembly

The car had been subjected to light corrosion over the years. The rotors were not spared. Although still functional may need to be replaced due to this issue or possibly lack of thickness as they will need be turned. Don't feel comfortable not attaching the hub to the rotor, so I'm researching the possibility of bolting the hub to the new rotor or sourcing new hubs with rotors. Thanks.

[Joe L.]

Re: 1966 Front rotor and hub assembly

The car had been subjected to light corrosion over the years. The rotors were not spared. Although still functional may need to be replaced due to this issue or possibly lack of thickness as they will need be turned. Don't feel comfortable not attaching the hub to the rotor, so I'm researching the possibility of bolting the hub to the new rotor or sourcing new hubs with rotors. Thanks.

Michael-----


It depends just how corrosion or otherwise damaged the rotors are. It may be possible to turn them on a brake lathe WITH THE HUB ATTACHED AND USING THE HUB AS THE "CENTERLINE" and still be within acceptable thickness. If there is deep pitting of the rotor it might not be possible, though.

Another approach would be to simply clean and dress the rotor surfaces using a 3M disc brake rotor kit. This will work perfectly to remove any light corrosion and impart a non-directional finish to the rotors. It will not remove pits, scratches and gouges, though. However, those may not need to be removed. It's absolutely not correct to assume that if a rotor has deep scratches or, even, pits that it has to be surfaced to remove them. Usually, these sorts of things will cause no functional problems. Rotor runout and thickness variations are the most important dimensional considerations from a functional standpoint.

As Mike mentions, the rotor rivets are not absolutely necessary. Many, many rotors used on modern cars have no rivets fastening the rotor to the hub, at all. In fact, this configuration is far more common than those in which the rotor is riveted to the hub. However, if you wish to attach the rotor to the hub, it can be done. I've done it many times. To do this, tap the existing rotor holes in the hub for 3/8-24. After tapping, make sure that you chamfer the holes at the rotor contact surface so that no upset material causes rotor runout problems.

Next, use a countersink on the rivet holes in the rotor. You will need to countersink just the holes, themselves, and not the counterbores for the rivet heads.

Lastly, use countersunk style, internal allen head, flat head 3/8-24 screws to fasten the rotor to the hub. Check to be sure that the head of the screws is AT OR BELOW the rivet counterbores. If not, countersink the rivet hole deeper so as to ensure that the screw head will not interfere with seating of the wheel on the rotor hub.

You can also look for rotors that are sold complete with hub as GM once serviced. However, I don't know that there are any out there. It's possible, though.

[Michael G.]

Re: 1966 Front rotor and hub assembly

Joe,

The surface itself is not pitted, just the outside perimeter. What is the least acceptable thickness as I know they can be turned but don't see the measurement on the rotor. My preference would be have them turned. Thanks.

[John H.]

Re: 1966 Front rotor and hub assembly

Joe,

The surface itself is not pitted, just the outside perimeter. What is the least acceptable thickness as I know they can be turned but don't see the measurement on the rotor. My preference would be have them turned. Thanks.

The minimum thickness spec is 1.215". If you have the rotors turned separate from the hubs (not a great idea), you'll need to set up a dial indicator when you re-install them and make sure the lateral runout is .004" or less, or you'll have air-pumping issues.

Most brake shops don't have a clue about the '65-'82 Corvette fixed-caliper brake system, and don't understand the importance of minimizing lateral runout; all they work on are floating-caliper systems.

[Michael W.]

Re: 1966 Front rotor and hub assembly

My preference would be have them turned.

Over the years, shops have gotten into the habit of turning rotors on disk brake cars as a 'routine' procedure. Probably 99% of the time this act was unnecessary (fixing something that was not broken) and simply machined off metal which in turn reduces ultimate service life of the rotor.

Because of this, many owners now believe that turning rotors is a 'good thing' and somehow benefits safety or stopping power. The opposite is true.

As mentioned above, separating the rotor from the hub, or substituting a new rotor on these cars brings you to a different maintenance task of having to measure and most probably correct run out of the rotor surface.

Is it possible for you to post a picture?

[Joe L.]

Re: 1966 Front rotor and hub assembly

Joe,

The surface itself is not pitted, just the outside perimeter. What is the least acceptable thickness as I know they can be turned but don't see the measurement on the rotor. My preference would be have them turned. Thanks.

Michael-----


If you're talking about the outside perimeter with the "vanes", that surface is essentially irrelevant to brake system performance. Also, that surface almost always rusts since it was not protected in any way.

I would check your rotors for run-out and parallelism. Procedure are described in the Chevrolet service manual. If they check out OK, then I DO NOT RECOMMEND HAVING THEM TURNED. The rotors on my 1969 have 200,000 miles on them and have never been turned. Not once, ever. If they check out OK, then I recommend obtaining the 3M Rotor Surfacing Kit I described (about $25 at better automotive supply stores) and use it to clean and surface the rotors.

[Michael G.]

Re: 1966 Front rotor and hub assembly

Here's a couple of images, front and back, which will let you see what I'm working with. The pad side surface is relatively unscathed, the leading edges of the perimeter are grainy as well as the hub of the rotor. Thanks guys.

[Joe L.]

Re: 1966 Front rotor and hub assembly

Michael-----


It's hard to say, for sure, from the photos, but I'd say that these rotors are fine for re-use if they check out ok with respect to runout, thickness, and parallelism. I would clean up the non -friction surfaces with a wire wheel on a drill and, then, do the friction surfaces with the 3M Rotor Kit.

Here's a couple of images, front and back, which will let you see what I'm working with. The pad side surface is relatively unscathed, the leading edges of the perimeter are grainy as well as the hub of the rotor. Thanks guys.

[Michael W.]

Re: 1966 Front rotor and hub assembly

Michael,
I had the children, animals and faint-of-heart women excused from the room prior to opening your post, fearing the worst.

That rotor is in excellent shape and does NOT need turning. The minor surface rust will come off with either the first application of the brakes or by using the kit that Joe recommends. My rotors only have a mere 130,000 miles (compared to Joe's 200,000) and don't look as nice as yours.

[Michael G.]

Re: 1966 Front rotor and hub assembly

I actually had my dog leave the room before posting these images fearing he may start howling .

Do any of you "swinging cats" happen to have the 3M part number for the rotor refreshing kit. Would make the search much shorter at the auto supply store. Thanks to everyone.

NOW.......gimme' that 3M part number...LOL.

[Joe L.]

Re: 1966 Front rotor and hub assembly

I actually had my dog leave the room before posting these images fearing he may start howling .

Do any of you "swinging cats" happen to have the 3M part number for the rotor refreshing kit. Would make the search much shorter at the auto supply store. Thanks to everyone.

NOW.......gimme' that 3M part number...LOL.

Michael-----


3M #01410

[Michael G.]

Re: 1966 Front rotor and hub assembly

Thanks for the assist. I have hope for these rotors now.

Mike

[Jim T.]

Re: 1966 Front rotor and hub assembly

Michael if you have to have new front rotors because of the current condition of your 66's and you want the new rotor attached check out www.bairs.com. Bairs can remove the old rotor and install a new rotor with rivets on your hub. They may have new rotors made in the USA.

I am partial to my original front rotors, my 1970 has 160K on its front rotors and my 68 has 98K on its front rotors and I have no reason to change rotors.