i am in the middle of a frame off resto. and am putting on new rotors what do i do where i drilled out the old rivits from the factory. will they work properly with just the lugs holding them. Your knowledge is appriciated. JR

 

JR, it's no problem. Just throw them on.

:cheers:

 

Don't forget to check the "runout" with the new rotor installed.

The old rotor was machined to be "true" when it was attached to the spindle.

Not all spindles have a true face. The new rotor may be true, however the spindle could be off by a few thou..

If the rotor does not run true, you will have brake problems.

 

I'm dealing with this issue at the moment. How can I go about making sure the face where the rotor attaches is true? I've heard of getting the rotors turned on the hub, what kindof a place has the machinery to do this, usually I take my rotors to OReilley's or the like and the have a machine for it.

-Chris

 

Gill - You don't have to install new rivets as the wheel/lugs will provide the clamping force needed to hold it all together.

RUX - I too am dealing with this presently. First I checked and corrected any runout on my new spindle faces at a machine shop. I then fabbed-up a 'torque plate' to simulate the clamping force of the wheel to the rotor/hub assy, and torqued it down to spec. This assy is now back at the machine shop to be checked/corrected via 'turning' the rotor if necess. A good machine shop will have machines large enough to address this. I have also requested a 'cross-hatch' pattern to be placed on the rotor faces for proper pad/rotor break-in. Hope this helps..... :chevy

 

Chris, ROD NOCK has given a good explanation on this.
I would check the spindle surface with a dial guage first to determine if they are true. A dial guage is not expensive and would make a great addition to the tool box.

If you have a dial guage, you can check the spindle flange, mark the high/low spot, then install the new rotor and check the runout again.
If the high/low spot is in the same spot on the rotor then chances the rotor is true.

However, if the reading is different, then the rotor may be off a little as well.
If so, then try it at different spots on the spindle.
Two 'wrongs', sometimes can make a 'right'.

If the spindle is out by more than .001, I would take it to a machine shop and have them true up the face. (Remove the wheel studs first)
I took one to a local machine shop here and he didn't even charge me. Only took him 5 minutes. (One pass on the lathe)

With the spindle face true, then you can check it with the rotor installed.
I just flip the wheel nuts and put them on with the taper out, and torque to 75 lbs.
If the new rotor does not run true, you then have one of three options.
- Return the rotor and try another one.
- Machine/turn the new rotor until true.
- Use a shim between the flange and rotor to bring it true.


Of course you can always use a shim to correct the runout and forget the machine shop. This method works well.

Just another note, if there is even a tiny bit of rusty scale on the spindle surface, this will distort all your readings. It must be very clean.
Barry

 

I disagree. One purpose of the rivits is to hold the rotor to the hub when you pull the wheel.
Without the rivits the rotor hangs at an angle causing the calipers to suck air. If you bleed brakes without rivits it's very hard since the rotor keeps moving around sucking more air into the caliper.

I tapped the hub for 3/8 x16 screws and it made a big diff on bleeding...
Remember to do all 5 or the wheel will be out of balance

 

I disagree with your disagree.
My opinion is based on my own experiences for the past 30 years.
My own vette has had the rivets drilled (rear) for about 25 years now. Had to in order to free up the emergency brake.
Before I went with SS calipers, I rebuilt the old calipers a few times.
The rotor does not hang at an angle and bleeding can be done quite easily with no problems.
If you have concerns, simply put on a wheel nut before bleeding.

For a few years I ran a Corvette repair business (spare time basis). I never had rotors without rivits cause a problem.

Why would the rotor be moving when you are bleeding??
Barry

 

Quick recommendation,if you're going to tap them go with 3/8-24 for more holding potential. I used 3/8-24 flat heads in the rear spindles. The rivet hole is just a little bit over the tap size drill, but it will still work.
The last one I did I just bolted them on and checked for run out. I had to shim new spindles and rotors too because the new (aftermarket forged!!!) spindles had 003-.005" runout .
Gary

 

i owned repair shops for over thirty years alot of which I speciallized in vetts. we always drilled out the rivets, installed new rotors, held them on with lug nuts when the wheels are off and bled the brakes. by the way if your calipers "suck air" replace them since the seals are no good anyway. wcj

 

I agree! I have done it!