Galco

Several months ago I installed new Zimmerman cross-drilled front rotors as part of my brake job. At 90Kmiles, OEM rotors were OK and could have been resurfaced maybe one more time, but nothing like fresh, thick rotors for that like new braking ability.

As most you know there aren’t that many options for non-OEM rotors for our D3s, let alone of the cross drilled variety. Found the Zimmermann’s at a reasonable price and they are performing nicely. However, despite the factory coating, the hats of the disc and vents gathered up quite a bit of surface rust, turning them rather unsightly for such a nice ride. Even though I live in a mild climate (Southern California) the surface treatment of the Zimmermann’s didn’t last and is rather disappointing. I couldn't take it anymore and decided to clean them up.

Below are before and after pictures (the how to is captured in the next post - due to limitations of the number of photos in a post)

Galco

Since I was unable to attached more than 5 pictures of the process in the original post above, here are the steps I took to clean up these rotors. Some pictures below to help in the explanation as well.

- Remove the rotors (requires jacking up the front end and place the car on jack stands, remove wheel, brake caliper and caliper bracket)
- Took to the surface rust with a drill mounted wire brush wheel and for the details and areas the wire wheel couldn't reach, I used a 3M scouring pad
- For the vents, sprayed the entire rotor with Navel Jelly’s rust remover and was surprised how much of the surface rust was removed chemically from the inaccessible vent opening on the edge of the rotor without the need of the wire brush or scouring pad
- Followed the Navel Jelly directions, apply, let sit for 5-10 min, rinse with water and dry before painting
- Masked off the rotor surface that would be touching the pads with blue tape and trimmed with a razor (good enough, not perfect as whatever paint gets in the way of the brake pads, won’t last too long and will be removed in the first few brake pad touches) Only painted the out facing sides of the rotor
- For paint I used silver VHT brand for temps up to 1200F which is way more than necessary for rotors but that’s what I had in the garage (I suspect VHT or other brands for up to 600-750F would be fine and would do that next time, reason why below)
- The VHT paint I used is a ceramic based paint and required heat curing for maximum adhesion and life expectancy, thus requiring about 3 hours in my outdoor grill at 250, 400 and 600F degrees for 30 min intervals and 30 min rest in between. This is why I would recommend the other types of high heat paint without the need for baking for proper curing. Well, I had the paint and the afternoon free so I followed directions
- Reinstalled rotors, caliper brackets, cleaned and greased up the caliper pins to reinstall the calipers all with proper torques (caliper bracket 140 lbs/ft; caliper pins 18 lbs/ft and wheel lugs at 90 lbs/ft)

There you have it and pics for reference. It’s been a few weeks now, holding up well and the interior of the wheels look much better than before. Personally, I prefer a silver rotor hat as silver more closely matches the wheel touching the hat as well as the color of shining part of the rotor from pad wear. Others will have their own preference including black or color match to calipers. For me and especially on a D3 – I’m keep it understated and let the wheels + body lines do the talking….

Hope this helps others!

Mike141

Looks very nice. What did you use to clean those calipers? Mine are black and it drives me crazy; black from bring so dirty and dusty. I have the same wheels as you so the caliper is very visible. I'd like to get my calipers that clean. Let me know. Thanks

Galco

G2 caliper paint is what I prefer as it holds up really well to wheel cleaners and brake dust. The spray on from rattle cans doesn't last as long.

Available in lots of colors. I took MP4s lead and did the 2 tone silver and black on the calipers. It was done about 5 years ago and is showing some signs of chips.

Robot Check

MP4.2+6.0

Simplified, what I do is spray new rotors with VHT brand silver before first use. Can get VHT from Amazon last I checked. I pre-clean rotors with rubbing alcohol to remove manufacturing or shipping oils, then spray. Lacquer thinner is another more volitile choice. I stack the two rotors to get the outer edge with no masking, focusing on the lowest rotor each time. I typically just spray hat area with no masking either, wiping off swept area with a paint thinner rag as I go for the overspray.

For used ones, I wire brush, then spray.

No issues with overheating w/ VHT with extended use on W12. Only issue I ever had was putting the outer retaining clips in an oven with clear coat over silver.--clear coat because of some logo type decals Turned them a great shade of gold if you ever want that. Net, skip the heat cure stuff (and don't use clear coat except with darker colors if you don't want yellowing). Brake use will heat the parts up anyway...

Galco

I agree, if rotors are not painted from the factory then paint them before installation. In my case the Zimmermann's were painted but the coating was really lousy!

1Wasserwerks

Nice job!
I cannot stand how easily these rotors rust up (especially after a good rain). The naval jelly looks like it did a great job. I always do this to new rotors, just using a quality engine paint.