Front rotor issues

Majin325 · 04:43 AM

I can't seem to get the rotors to seat flush with the hub. These are new rotors that I installed and took them off due to vibrations while breaking. Torqueing the bolts to 30ft/lbs I can still see light gaps between the rotor and hub. With the hub back on I can spin the hub but the rotors don't spin straight like they are warped but they aren't(checked by placing them on a flat surface). I can hold a tool in place to check if it spins straight but it doesn't. There is about a 1 millimeter wobble on both rotors.

Do I just torque the hell out of the bolts till the rotor is seated all the way then tighten to 17ft/lbs when done? 17ft/lbs? Seems like it wouldn't be tight enough.

Here is a quick video. You can hear the scraping when the rotor turns and even see it wobble. These bolts are torqued to 30ft/lbs loosened and re-torqued to 17ft/lbs.

https://youtu.be/k9_-Okq4kss

This is the rotor sitting on the hub unseated.

Alexb944 · Alexb944's Garage

is the hub itself warped?

Majin325 · 08-27-2016, 04:19 AM

I don't think so but didn't check. I didn't have the vibrations with the original rotors though.

Alexb944 · Alexb944's Garage

possibly with the old rotors they warped with the hub and kind of counter balanced the wheel. happened with my sc300 a while back.

Bukowski · 08-27-2016, 04:36 AM

I scrubbed the hubs well, including rotary tool polish in certain spots. My hubs were ratty on the edges. Let's not go there. My rotors were new, so they were perfectly flat. I used high T ceramic grease.

HTH.

Majin325 · 04:46 AM

Here is a quick video. You can hear the scraping when the rotor turns and even see it wobble. These bolts are torqued to 30ft/lbs loosened and re-torqued to 17ft/lbs.

The hub doesn't look like it wobbles at all in the video.

https://youtu.be/k9_-Okq4kss

mytrplseven · mytrplseven's Garage

It sounds to me like you may have the wrong rotors. I'd recommend you consult with the place you bought them from to confirm proper part numbers.

Majin325 · 08-27-2016, 05:23 AM

Quote:

Originally Posted by mytrplseven

It sounds to me like you may have the wrong rotors. I'd recommend you consult with the place you bought them from to confirm proper part numbers.

I bought them here from pelican
Zimmerman coat Z Part #: 477-405-083-D-M359

peteb · 06:58 PM

Hi,

The hub has to be super clean before the rotor will seat correctly. I spent about an hour per hub with a wire brush and fine emery cloth on mine. The rotor should drop on the hub with no force and it should rotate freely on the hub before bolting. No visible light gaps at the seating surfaces. Our cars are old enough that a lot of crud has had time to build up on the hub/rotor interface.

The lateral runout specification is 0.05 mm maximum at the rotor edge. Best to measure after installing the brake.

Best of luck,

Peter

Majin325 · 08-27-2016, 06:49 AM

Quote:

Originally Posted by peteb

Hi,

The hub has to be super clean before the rotor will seat correctly. I spent about an hour per hub with a wire brush and fine emery cloth on mine. The rotor should drop on the hub with no force and it should rotate freely on the hub before bolting. No visible light gaps at the seating surfaces. Our cars are old enough that a lot of crud has had time to build up on the hub/rotor interface.

The lateral runout specification in 0.05 mm maximum at the rotor edge. Best to measure after installing the brake.

Best of luck,

Peter

I'll have to see what I can do about cleaning the hub mounting surfaces to get them to spin freely on the hub. The original rotors seemed like they were pressed in by having to hammer them off the hub. It's probably due to build up and old age.

Rasta Monsta · Rasta Monsta's Garage

Have them bead blasted. They look beautiful when they're super clean.

Sent from my Nexus 6P using Tapatalk

peteb · 08-27-2016, 09:39 AM

I had to hammer my old ones off too. Just because of all the rust and crud. They are not a press fit when they are new.

Peter

dgcantrell · dgcantrell's Garage

As mentioned above, have them bead blasted. The aluminum will corrode in contact with the steel rotors and cause them to basically try to fuse together so to speak because they are dissimilar metals. When you get them cleaned and the rotors fit, paint them with some aluminum engine paint. Put a couple of good coats on. Then when fitting the rotor back on, slather the mating surfaces of the rotor and hub with anti-seize compound. This will help prevent any oxidation of both to make them a HELL of lot easier to take apart the next time. I'm a firm believer in using anti-seize in places like that. I can sure tell you that when the next time you have to do this job, you'll thank yourself for using it.

brian19600 · brian19600's Garage

I had the same problem with the rear rotors. I bought new rotors and they wouldn't sit flush. I thought maybe the e brake shoes were hanging it up and I checked all sorts of things. Finally after taking some measurements, I determined that there was an area that wasn't machined enough inside (past where the shoes ride) and it was preventing the rotor from sitting flush on the hub. So I put a drum sander on my dremel tool and went around it a bunch times and that fixed it. I would have returned the rotors but I had them for too long. These were not the cheapest rotors either. I think they were beck arnley.