I have my front rotors all cleaned up and plan to paint them with gray VHT high temp paint. I'm reading conflicting opinions about painting the contact area on the faces. I was thinking I'd just paint the whole thing before having them resurfaced. One camp seems to think painting the whole rotor and letting the pads take the paint off the contact area is the way to go. Makes sense for leaving only the contact area unprotected but I worry about fouling the pads. What do you experts say?

No way. Paint has oils in it.

Indeed! I agree completely

I wonder if people zinc plate them? If so just plate them at your place.

Bob B

Found an old thread where Eric recommended doing just that and then painting the hats. Unfortunately, I can't plate something that large with my setup.

never paint rotor faces

Make paper masking discs to cover the brake pad contact area. Tape and trim the inner circle. . . Paint only the center hats. . I never used VHT. . Plain ol dove gray in Krylon is sufficient unless you're tracking the car [ or have a dragging brake pad ]

Thanks guys. That matches my instinct that painting the faces would be a bad idea, but what do you think about painting without masking BEFORE having the rotors turned? Seems like there wouldn't be any harm in letting the lathe take off any overspray. However, now that I have the rust cleaned off, I don't think they need turning. I think I'll mask and paint them, then mount them and check for wobble before making that decision.

I already have the VHT on hand from painting the caliper piston tops so I might as well use it.

Brent,

I think you can just use a big bucket with the zinc set up. I can see it in my mind after doing smaller parts like you have done. Steel wool after and then whatever. Just leave the vinegar and the zinc sit for a week or more so the partials go into suspension. I let mine sit for a long time and the solution worked much better.

Your car is really nice. Super job on your end.

Bob B

Problem is my power supply. Max 5 amps. I tried doing a caliper half and didn't have much luck. Will try again but even that seems to be at my limit. I haven't tried it with an epsom salt and vinegar bath though. Might be a little more forgiving?

since a wear item to be replaced in the future, just use zinc paint on the hats only

I just realized that to plate these will require knocking the bearing races out. My bearings are in good shape so I think I'll just stick with paint on this round. Rears will be getting new Sebro coated rotors.

Yep, , this is what I've been planning to do myself.

How about Cerakote ? Pretty durable and a testor amount would be plenty to spray everything needed.

Don't paint the rotor swept surfaces. I wouldn't even recommend the zinc plating of swept surfaces.

I did design and engineering release of brakes systems as my day job. Rotor coating is a problem even within OEM industry. We used to "paint" them with a special coating to prevent rust during overseas shipment and while sitting on dealer lots (i.e. Lot Rot) to prevent judder that comes from disk thickness variation stated by localized corrosion.

Developing those coatings was a huge undertaking. When the industry was forced to switch from coatings that contained Hexavalent Chromium in the early 2000's it kicked off a switch to Zinc based coatings. We had all kinds of issues with balling of the coatings, and transfer of the coatings into the pad linings. You will not generate enough heat in the rotors to bake out the zinc once it has transferred to the pads.

Pad contamination can result in all sorts of side effects ranging from decreased friction (i.e. much longer stopping distances) to generation of brake judder, to rotor scoring.

If you do decide to paint the hats, tape off the area where the wheels contact the rotors. Having paint in the joint between the wheel and the rotor face can lead to a loss of wheel lug nut torque as the paint either crushes out or frets away over time. Loss of wheel torque rarely ever ends well. At best you get some vibrations that alert you to loss of torque. At worst, wheel will separate from the vehicle without much warning. You'd be amazed that this can happen but I assure you it can.

Typical OEM Coatings that have been used successfully for rotor coatings:

Dacromet:
http://www.nofmetalcoatings.com/_upload/re...dacromet-gb.pdf

Geomet:
https://www.anochrome.com/wp-content/uploads/2012/01/NOF.pdf

Good info, never thought about brake-to-wheel contact area

I've seen this, luckily in trial fitting. If you already did paint try torquing it up a couple times, it will break up a fair bit of the paint.

Well, I have and I will. Taking them in to be turned today.

This is interesting though because back when I was driving this car, I started having serious problems with my Fuchs fusing to the rusty rotors making it near impossible to pull the wheel off. I once even lowered the car back to the ground with the wheel bolts out trying to use the weight of the car to break the bond. It didn't work and the unbolted wheel held the whole weight of the car! Trying to avoid that problem was a major reason why I wanted to paint the hats. Has anyone else had that problem?

BTW, failing to torque the bolts before jumping in the car to hurry back to college after a weekend of wrenching in dad's garage can also cause a wheel to leave the vehicle at highway speeds. I was a stupid kid. I can tell you that with bolts, there isn't much warning before you watch a rogue wheel go rolling down the road in front of you. Then lots of sparks.

This is interesting though because back when I was driving this car, I started having serious problems with my Fuchs fusing to the rusty rotors making it near impossible to pull the wheel off. . . . . . . Has anyone else had that problem?


This is a common problem on aluminum wheels. It is caused by Galvanic corrosion between steel and aluminum. water, and especially water with a little salt causes the two dissimilar material to become a minute battery, flowing a minuscule amount of current between the two metals. Crazy but true. The ionization at the surfaces fuses the materials via corrosion over time.

My solution for years has been to use just a light dab of anti-seize between the surfaces where they contact. Problem solved. . . . well sort of. It's not ideal to have grease between the joint either since it will then take more clamp load from the wheel studs to keep things from moving relative to each other that can also cause a loss of clamp load. In practice, I've never found this to be a problem on low horsepower vehicles. Just don't use a lot of grease - I just put a dab on my finger (use a rubber glove if you don't want stained fingers) and rub it on. Very Thin. Wipe off any excess.

This trick works especially well on wheels that are hub-centric with close tolerances between the hub pilot and the wheel bore.

Good general practice is check lug nut torque (with a torque wrench) after driving about 10 - 20 miles then check and then again around 100 miles later. If they have lost torque more than a few lb-ft of torque, something is wrong.

By the way - - - similar story on loose lug nuts as a youngster. You are not alone